# Modifying a MASTERBUILT?



## Atl1530 (Jun 24, 2019)

I have an old MASTERBUILT smoker.  Parts are hard to find or nonexistent.  The digital control panel screen is going out, and it's hard to see the numbers, which makes it hard to set the temp. I have looked, and new digital control panels for this model are no longer available. 

All I really need is a rheostat controller to set the element. I use a third party thermometer to monitor the smoker and meat temperature. 

Has anyone done this before? 

Thanks


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## pounce (Jun 24, 2019)

Hard to know about your model, but you can make one of these dumb pretty easy by rewiring the leads from the relay on the PCB directly to the power cable. I might recommend considering a PID controller when you do this, but a rheostat would work if you found one that could handle the wattage.


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## johnmeyer (Jun 24, 2019)

There are dozens of posts about how to use a 3rd-party controller with pretty much any MES. Most of them are PID, which is overkill IMHO, but since you can't beat their accuracy, and since "PID" makes it easy to search the forums, why don't you try searching on that and see if you can come up with something that will work for you?


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## JC in GB (Jun 24, 2019)

Don't use a rheostat.  You will waste too much power.  An AC phase controller is what you need.  You can also run your element with a PID controller and a solid state relay (SSR).


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## Atl1530 (Jun 24, 2019)

pounce said:


> Hard to know about your model, but you can make one of these dumb pretty easy by rewiring the leads from the relay on the PCB directly to the power cable. I might recommend considering a PID controller when you do this, but a rheostat would work if you found one that could handle the wattage.


Yes the more I think about it I am sure an on-off controller would be better then a rheostat Thanks


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## pounce (Jun 24, 2019)

Atl1530 said:


> Yes the more I think about it I am sure an on-off controller would be better then a rheostat Thanks



Depends. I think the control would be better. With a rheostat you might be left making micro adjustments during a cook. That might be ok or it might be annoying. I think a controller is worth the money because I can walk off and know that the temp will remain what I want it to be. Not creep up as moisture is decreased and the food is closer to done.


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## tallbm (Jun 24, 2019)

Atl1530 said:


> Yes the more I think about it I am sure an on-off controller would be better then a rheostat Thanks



Hi there and welcome!

I am always a proponent of a PID controller and rewiring the MES for it.
To answer your originaly question I believe 

 daveomak
 did something similar to what you initially suggested with an electrical stove controller... I think. 
He should be able to give you more details and/or point you to the post.

It's all up to you but I know from personal experience that the PID controllers are nice and mine keep within 3 degrees of the set temp :)


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## daveomak (Jun 24, 2019)

Atl1530 said:


> Yes the more I think about it I am sure an *on-off controller* would be better then a rheostat Thanks



I've been using a rheostat for 7-8 years....   Mo Betta than an on off controller IMO...  The element never turns off....  You adjust it like a gas burner stove...   No up and downs with the smoker temp...   As the smoker warms up, or the ambient warms, you will have to turn the heat down a bit...    It's a little intuitive to operate but the constant heat is worth it to me....
There is a newer SCR on the market I found..  I have 2...  use them to control the heat output of electric skillets etc. and variable speed control on those immersion blenders...  awesome unit....  considering cost...  at 7 cents/KWH it costs less than 4 cents per hour to operate...  I'm cheap but............

 SCR speed/voltage controller 

...


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## Atl1530 (Jun 24, 2019)

That's Perfect 
I pulled the digital controller off the smoker, thinking there would only be two wires coming up from the elements, but there were 4. Any advice on how to wire it up? 

Thanks


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## tallbm (Jun 24, 2019)

Atl1530 said:


> That's Perfect
> I pulled the digital controller off the smoker, thinking there would only be two wires coming up from the elements, but there were 4. Any advice on how to wire it up?
> 
> Thanks



Here is detailed info on how to rewire so the plug simply feeds power to the heating element BUT keeps the safety rollout limit switch in the mix in case of an overheating situation: https://www.smokingmeatforums.com/threads/mes-rewire-simple-guide-no-back-removal-needed.267069/

Enjoy :)


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## chopsaw (Jun 24, 2019)

Atl1530 said:


> That's Perfect
> I pulled the digital controller off the smoker, thinking there would only be two wires coming up from the elements, but there were 4. Any advice on how to wire it up?
> 
> Thanks


Under the controller you have the wires for the on board meat probe . Is that what you are seeing ? I have a gen 1 30 . It has a plug for the thermostat and a plug for the meat probe .


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## pounce (Jun 24, 2019)

daveomak said:


> I've been using a rheostat for 7-8 years....   Mo Betta than an on off controller IMO...  The element never turns off....  You adjust it like a gas burner stove...   No up and downs with the smoker temp



There really isn't any effective on/off with a PID controller with these cookers. The burner is always going to be generating heat. Think of it like trying to simmer a frying pan using a full flame on the stove. You might put it on for a few moment and then take it off. You wait a bit and then put it back on. By doing this you are leveling the temp, but the pan is still hot.

The big difference in the two approaches in is usability. Say you are cooking and you need to open the door to move things around or mop something. There is a huge heat loss. A controller will recover this quicker as it will power the burner at some degree of full power (based on the PID settings) and then back off to recover to your hold temp correctly. If you so this with a rheostat you manually crank it up...guess when to back it off and then through trial and error know where to set it to hold the temp you want with the content you have etc.

There are no ups and downs with a PID controller. That's the objective of having one.


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## Atl1530 (Jun 25, 2019)

chopsaw said:


> Under the controller you have the wires for the on board meat probe . Is that what you are seeing ? I have a gen 1 30 . It has a plug for the thermostat and a plug for the meat probe .



I will look at it again. I just assumed that there would be two wires coming up from the elements running into the controller and all the probe wiring would be separate. I guess nothing is as simple as you think it will be.


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## daveomak (Jun 25, 2019)

pounce said:


> There really isn't any effective on/off with a PID controller with these cookers. The burner is always going to be generating heat. Think of it like trying to simmer a frying pan using a full flame on the stove. You might put it on for a few moment and then take it off. You wait a bit and then put it back on. By doing this you are leveling the temp, but the pan is still hot.
> 
> The big difference in the two approaches in is usability. Say you are cooking and you need to open the door to move things around or mop something. There is a huge heat loss. A controller will recover this quicker as it will power the burner at some degree of full power (based on the PID settings) and then back off to recover to your hold temp correctly. If you so this with a rheostat you manually crank it up...guess when to back it off and then through trial and error know where to set it to hold the temp you want with the content you have etc.
> 
> There are no ups and downs with a PID controller. That's the objective of having one.



Thank you for pointing out how incorrect I am...  It's always appreciated when I'm voicing my opinion...


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## tallbm (Jun 25, 2019)

Atl1530 said:


> I will look at it again. I just assumed that there would be two wires coming up from the elements running into the controller and all the probe wiring would be separate. I guess nothing is as simple as you think it will be.



You had the right idea but looked at the incorrect spot.
The wires you are seeing run from a circuit board that is located in the bottom of the MES (flip it upside down and you will see the panel for the board on the bottom.

What happens is the plug runs into the back of the MES (3 wires in the plug).
The ground runs to a ground spot.
The Neutral and Hot wires run to the circuit board.

From the circuit board the neutral and hot will then be directed through braided wires onto the heating element.
The Neutral runs directly to the heating element.  The Hot wire runs up into the MES to the safety rollout limit switch and then from the switch to the other prong of the Heating element.

Also from the circuit board the voltage is stepped down and run upwards to the controller on the top of the MES via the little wires you are seeing.

Putting that all together, you were close to the right idea but looked in the wrong spot.  The circuit board at the bottom splits the power off between the controller on top and the heating element and that is where you were tripped up :)

The rewire works by taking the plug wires and splicing them with the Neutral and Hot braided wires that come out of the circuit board that then go on to the heating element (hot wire detouring to include the heat safety rollout limit switch).  So splice the proper wires to bypass the circuit board and the controller on top and you have a dumb circuit that feeds power direclty to the heating element.  (This is where a PID controller can come in and make life easy).
I hope this info helps! :)


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## Atl1530 (Jun 25, 2019)

Thanks


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## pounce (Jun 25, 2019)

Atl1530 said:


> Thanks



Snap a photo and attach it if you need help. Seems like the controller boards vary a little, but it's pretty easy to sort out what to cut by looking at them if you can read a PCB. Happy to mark of a photo to help.


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## johnmeyer (Jun 25, 2019)

pounce said:


> The big difference in the two approaches in is usability. Say you are cooking and you need to open the door to move things around or mop something. There is a huge heat loss. A controller will recover this quicker as it will power the burner at some degree of full power (based on the PID settings) and then back off to recover to your hold temp correctly. If you so this with a rheostat you manually crank it up...guess when to back it off and then through trial and error know where to set it to hold the temp you want with the content you have etc.
> 
> There are no ups and downs with a PID controller. That's the objective of having one.


I agree.

The rheostat wastes a huge amount of energy and generates a lot of heat. It would not be my first choice for controlling something that is close to 1,000 watts. If you want to go that route, at least use a triac light dimmer (as SCR is not as good because it only works on half of each AC voltage cycle).

However, any sort of controller that uses a temperature sensor to turn the heating element on and off will give you much better temperature control and, as correctly pointed out by "pounce," will recover the temperature _much _faster after you've opened the door. 

So, this is really what you should use.

These controllers are so inexpensive and so easy to wire (there are dozens of threads in this forum on how to do it), that there is no reason not to do it that way.


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## sigmo (Jun 26, 2019)

I  doubt that anyone is really using a true "rheostat" to control the power to their smoker heating element.

People sometimes use the word "rheostat" (incorrectly) to mean a power controller of any type.

Technically, a rheostat is simply a variable resistor.  This is distinct from a potentiometer in that it has only two terminals versus the three of a potentiometer.

For a rheostat to be used to control the power of one of these 800 to 1200 Watt heaters, the rheostat must be sized to handle dissipating the power created in the portion of its resistive element that has been set to be in series with the heater.  The worst case ends up being near one end of that element when you've adjusted it to give almost, but not quite, full power to the heater.  In that range, the current through that small section of the element will be near its highest, and that heating will be concentrated into a small area of the element.

Thus, usually, rheostats will be rated for a maximum current rather than a maximum power dissipation.

In any case, a true rheostat would be very large to handle the current that one of these smokers' heating elements would draw.

Further, using a rheostat to control the power to a heating element becomes rather unintuitive because of the non-linear relationship between the amount of rotation of the knob, and the power to the load.  Sometimes you see specially-wound rheostats that have a non-linear character designed to compliment a specific heating element or load so that the power to the load will be somewhat linear with respect to the rotation of the shaft.

But what people normally mean, when they say "rheostat" is an SCR or TRIAC based phase control device like a lamp dimmer.

Most SCR-based units use "back to back" SCRs to achieve full-wave control.  These are usually more rugged than the TRIAC-based units.

Nobody really uses rheostats these days.  And even in the past, for high power applications, people usually used variacs (variable transformers) to both maintain linearity of control and efficiency.

So I'm pretty sure, when someone says they are using a rheostat to control their smoker, what they mean is that they're using a phase control device.

You can get small phase control units meant to control the speed of small motors and the like.  And that's likely what folks mean by "rheostat" these days.

I, too, prefer an actual temperature controller.  And I prefer a controller that employs proportional control so that temperature cycling is minimized.  PID is nice, and very inexpensive to implement these days, so that's what you often see.

In any case, as tallbm and others have pointed out:  It's almost a blessing that your unit's controller has failed.  A better controller may well be a noticeable improvement over the stock system.

But be advised:  You will need a different means of generating the smoke if you go with one of these replacement controls because the heating element won't cycle on full blast at times the way the stock controller makes it do.  So the chip burner won't work.


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## Atl1530 (Jun 26, 2019)

Simgo Thanks for you input
daveomak is using one of these which is what you're talking about I think. I like the idea of the elements not turning off and keeping a very steady temperature. Any reason shouldn't is one of the ends. There are less than $20.


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## daveomak (Jun 26, 2019)

SCR speed/voltage controller 

About wasting electricity....
If you are controlling a 1000 watt element, and you use 1/2 the current to control the temperature and wasting 1/2 the currrent.....
at 10 cents a KWH, you are wasting 5 cents per hour of operation to control your smoker..   a 10 hour smoke, that's 50 cents used and 50 cents wasted... 
With an ON-OFF controller, you are using 1000 watts during the heat up cycle and ~0 watts during the off cycle... 
The difference in cost could be calculated..  So can the difference in cost of a ~$100-150 PID vs. the cost of an $8.99 SCR...   Your choice...


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## JC in GB (Jun 26, 2019)

DaveO when you said rheostat, I thought you were talking about the old style variable resistors.  I see you were referring to AC phase controllers all along.

I agree with you that the AC phase controller gives nice steady power to the element.  I like that level of control even with a PID controller.

A PID with an on/off only to the heating element creates a bang-bang kind of control with the element being fully on of in a non-powered state.  Even though the PID smooths the temp fluctuations out, they are still there whereas they would not be as pronounced with a controlled analog power flow.

The ideal situation with a PID, analog controller or even the pit master operating the pit would be to precisely control the amount of heat delivered to the food without having to constantly make adjustments to power, air flow, fuel load, etc.  In the case of the electric smoker, you would want your element on all the time at the proper power to regulate the chamber temp with it never turning fully on of off.

With the digital controls, you don't get that option.  As far as the recovery from opening the cook chamber, a turn of the AC phase controller has your element back at 100%.

All this said, if I was setting up this smoker, I may use both a PID and phase controller so I could regulate overshoot especially for low temp smoking.

My $0.02.....


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## daveomak (Jun 26, 2019)

My error....  It's actually a 1500W dimmer.....







	

		
			
		

		
	
 ...


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## Atl1530 (Jun 26, 2019)

daveomak said:


> My error....  It's actually a 1500W dimmer.....
> 
> View attachment 399041
> 
> ...


Do you have any photos on how you wired it up


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## pounce (Jun 26, 2019)

JC in GB said:


> A PID with an on/off only to the heating element creates a bang-bang kind of control with the element being fully on of in a non-powered state.  Even though the PID smooths the temp fluctuations out, they are still there whereas they would not be as pronounced with a controlled analog power flow.



The devil is in the detail here though. Think of the PID controller powering the element like a PWM signal. It sends power and then stops and waits and then sends power. The square wave of this is roughly equal in actual practice to variable voltage. With an Auber control you can see the cycling with an LED. In an older house and a higher powered element you can probably see it in your incandescent lights flickering on a regular pattern.

By cycling the power the PID controller can keep the element at a temp equal to the same way you could do it with a dimmer switch or an SSVR etc.

I'd argue there are no real temp fluctuations when a controller using a relay is controlling the temp of an element with PID.


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## Bearcarver (Jun 26, 2019)

tallbm said:


> Hi there and welcome!
> 
> I am always a proponent of a PID controller and rewiring the MES for it.
> To answer your originaly question I believe
> ...




Atl1530,
I totally agree with the guys suggesting a PID.
Everyone who has gotten one for his MES is Pleased as Punch.
I'm sure 

 tallbm
 ---Will help you in picking a good one & switching yours over.
He is my Electronics GOTO Guy!!

Bear


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## Atl1530 (Jun 26, 2019)

Bearcarver said:


> Atl1530,
> I totally agree with the guys suggesting a PID.
> Everyone who has gotten one for his MES is Pleased as Punch.
> I'm sure
> ...



When you guys are talking PIDs are you talking about the Auber Instruments PID? I contacted them yesterday, and their cheapest unit for my smoker is $120.00. I am not sure why they are so great.  Do they hold the temperature precisely? Daveomak's $12.00 SCR speed/voltage controller seems like it would work also. I have a digital thermometer, so I know what the temperature is inside the smoker.


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## JC in GB (Jun 26, 2019)

Atl1530 said:


> When you guys are talking PIDs are you talking about the Auber Instruments PID? I contacted them yesterday, and their cheapest unit for my smoker is $120.00. I am not sure why they are so great.  Do they hold the temperature precisely? Daveomak's $12.00 SCR speed/voltage controller seems like it would work also. I have a digital thermometer, so I know what the temperature is inside the smoker.



I put together a PID controller for under $20.  There are many good pit controllers on the market.  I just didn't want to pay for one I could put together myself.


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## Bearcarver (Jun 26, 2019)

Atl1530 said:


> When you guys are talking PIDs are you talking about the Auber Instruments PID? I contacted them yesterday, and their cheapest unit for my smoker is $120.00. I am not sure why they are so great.  Do they hold the temperature precisely? Daveomak's $12.00 SCR speed/voltage controller seems like it would work also. I have a digital thermometer, so I know what the temperature is inside the smoker.




There are others who know a lot more about PIDs than I do.
That's why I put the link to 

 tallbm
 for you.
The way I figure it, the PID makes adjustments to keep it at a steady temp, without you having to do any adjustments like I've been doing for 9 years with my MES controls. Others can tell you much more.

Bear


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## JC in GB (Jun 26, 2019)

I agree with you mostly pounce.  If you can switch the element on and off quickly, you will get an average power going through the element that will be nearly as smooth as an analog control.  The way my system is set up, the fan to the firebox is either on or off.  If you combined your PID controller with PWM output, you would have very smooth control.  A nice thought but considering the thermal time constant of most smokers, that level of control would likely not be necessary.


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## pounce (Jun 26, 2019)

JC in GB said:


> I agree with you mostly pounce.  If you can switch the element on and off quickly, you will get an average power going through the element that will be nearly as smooth as an analog control.  The way my system is set up, the fan to the firebox is either on or off.  If you combined your PID controller with PWM output, you would have very smooth control.  A nice thought but considering the thermal time constant of most smokers, that level of control would likely not be necessary.



Since we are posting in Electric smokers we assume the PID controller is powering an electric heating element. The reaction time of an element in the MES is pretty slow. It does not go instantly hot and it certainly doesn't cool quickly esp in a heated box. Power on for 1 second and then power off for a second using a relay is coarse PWM but the real world result is a burner that stays hot with no fluctuations, but not the same hot that you would get at 100% power. With these heating elements and the type in a Bradley you don't need to cycle quickly to keep a temp anywhere in the range.


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## daveomak (Jun 26, 2019)

Disconnect the 2 wires from the element.....   
Connect them to the "INPUT" side screws on the SCR...
Connect new wires from the SCR "OUTPUT" to the element....
Done....  
The over temp sensor will still turn off the element is the unit gets too hot....
The controller to stop the temp from getting above say 150F, will still turn off the element when the smoker gets to 150F...
Everything is exactly like it was before the install....  EXCEPT, the element can be controlled to what ever heat output you want....
To operate like a gas burner, turn the temperature set point you want to cook at, 10-15 degrees above the desired temp...
Adjust the SCR to full output...   Watch the smoker temp... As it approaches your desired temp, decrease the voltage...  After awhile the temp will stabilize...   Adjust the SCR up or down until the smoker is in the range you are wanting...  Remember or mark settings for future reference... 
After the first smoke, you will have a good idea where the settings will be for a desired temp...
I shoot for anything within +/- 10-15 degrees..   as the smoker and meat heats  up further adjustment may need to be made depending on how tight a control you are wanting...


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## sigmo (Jun 26, 2019)

Atl1530 said:


> Simgo Thanks for you input
> daveomak is using one of these which is what you're talking about I think. I like the idea of the elements not turning off and keeping a very steady temperature. Any reason shouldn't is one of the ends. There are less than $20.



I couldn't see the item linked in your post, but viewing at subsequent post by Dave, I see he is using a phase control gadget.  Basically, a high power dimmer, as we've been discussing.

The advantage of his setup is that it's inexpensive, and gives efficient power control to his heating element.  He's got it marked with settings to achieve various temperatures.

However, the disadvantage is that this is not an actual "temperature control".  Instead, it's a "heat control" or "power control".

Think of this as being like the heat control for an electric burner on a typical range.  You can adjust the average power to the burner, but you must determine by trial and error what setting gives you what you want.  There is no actual monitoring and self-adjustment of the system to achieve any particular temperature.

On the other hand, a temperature control system uses some sort of self-monitoring or "feedback" to actually control the temperature to the setpoint the user enters or dials-up.

This is like a thermostat for a furnace or oven.  You set the temperature you want, and the controller (thermostat) adjusts the power to the heater to achieve and maintain that temperature "setpoint".

As folks have pointed out, you can spend quite a bit and buy a pre-built PID temperature controller that comes with everything you need.  Or you can build one yourself, rounding up the necessary parts, and do it for considerably less.  It depends on how much of an electrical or electronic do-it-yourselfer you are, and how comfortable you are with your skills in that area.

To the points about wasting power.  The phase controls like Dave's won't waste much power at all.  They're quite efficient because of the way they switch the power on and off.

The old rheostat setups would waste quite a bit of power, but as we've established, nobody is actually using a rheostat, so that's a moot point for our discussion.

Neither a dimmer like Dave's or a fancy PID system will _have to_ cycle the power to the heating element slowly enough to see any "ups and downs" in the cooker's temperature.

Even with a dimmer like Dave's, the TRIAC or SCRs switch the power to the heater on and off fully.  This fully on and fully off switching is what makes these devices power efficient.  The power control elements are either conducting fully, or switched completely off.  Yes, there's a little bit of voltage drop across them in their "on state", but only a few volts worst case.  So the power wasted is tiny.

These dimmers are called "phase control" devices because of how they switch the power on and off.  With both SCRs and TRIACs, there is a trigger input that can cause the device to begin conducting.  Once you've triggered the device "on", it cannot be shut off.  However, because the power being controlled is AC, it shuts itself off at the next available zero-crossing point in the current waveform.

So if you trigger the device "on" when the phase of the available voltage is halfway through its half-cycle, the device will remain on for the rest of that half-cycle, then shut itself off.  So you will get one half of one half-cycle, or 1/4 of a full power cycle.

So these dimmers employ a simple setup using a DIAC, resistor, and capacitor to develop a triggering pattern that lets you adjust when, in each cycle of the mains power, the TRIAC or SCRs are triggered.  This cycle of switching the power on within each available power cycle is repeated every 120th of a second (once for each half-cycle of the 60Hz mains power)  (50Hz if you're in England).

If you have the adjustment potentiometer set fully clockwise, the circuit will trigger the SCRs or TRIAC very early in each power cycle so that the conduction takes place over almost all of the full half-cycle each time.  If you set the potentiometer closer to counter-clockwise, the device will be triggered nearer to the end of each available half-cycle.

Thus, you can adjust the average power to the load over a wide range.  But it's important to realize that the power _*is*_ being switched on and off.  It's not continuous power being fed to the load.

But at 120 pulses per second, the typical heating element appears to be powered continuously simply because its mass is great enough that it cannot vary in temperature much at all in such a short period of time.  So the effect is smooth heating with little or no observable "on-off" effect.

A detail often overlooked is that because the typical dimmer control circuit provides a linear adjustment of the _timing_, the actual power delivered to the load is NOT linear with the position of the potentiometer.  That's because the waveform of the incoming mains power is a sine wave, and you're triggering the SCRs or TRIAC at different points in each half-cycle of that sine wave.  Obviously, at the extreme ends of the pot rotation, you're getting less of an effect on the average power than you do near to the middle of the range because the power waveform is nearly zero at the beginning and end of the half cycle, but quite high when you're near the center of the half cycle.

But if we're not actually controlling the temperature, but instead controlling the power with the pot, we need to use trial and error anyhow, so it doesn't matter too much.  But just be advised that there will be a lot more adjustment happening when you're near the middle of the pot's rotation than when you're at the extremes.

This is a drawback of phase control.  There are fancy systems that take this non-linearity into account and translate the user's power pot adjustment into a modified timing scheme to try to simulate linear power control, but at that point, you're now paying a lot more for the circuitry.

OK, now we get to various actual temperature controllers.

No mater what sort of controller we use, we still need to control the power to the heating element.  And to be efficient, we'll have to switch that power on and off fully if we want good efficiency.

This can be done with a mechanical relay (as my Masterbuilt unit does) or a solid-state relay.

A mechanical relay has a limited cycle life, so to make it last longer, designers choose a relatively long cycle time.  That cycle time can be so long that the heating element actually does change temperature.  At the extreme, as with the stock MES controller, the power is switched on and off to the heater over a very long cycle time.  This achieves two things for the MES.

One is that it makes their mechanical relay last longer.

But the other, more subtle effect, is that it allows their chip burner to function to deliver smoke.

To get the chips hot enough to smolder, the heating element needs to be on "full blast" for time periods long enough to let it get red hot and stay there for a while.

But that also leads to large swings in the temperature of the smoker itself.  There's no way to get around that. If you want the chip burner to work, you must use a long cycle time for your control system so that you'll get the heating element red hot for long enough to ignite the chips every so often.

So people often complain about the way their MES's temperature cycles up and down.  But unless you use a different smoke generating system, you're stuck with those temperature swings in this design.

But people here often use something different to get their smoke, anyhow, because we often find the chip burner to not work as well as we'd like.  So if you're going to use a separate smoke generator, you are no longer married to those large temperature swings.

So at that point, you can use a dimmer like Dave's using, or any of the various temperature controllers to set your smoker's temperature.

PID controllers are popular because they can be "tuned" to provide tight, but responsive temperature control.  There's a lot to that.  But suffice it to say that a PID controller has the potential to work quite well for our smokers.

And also note that in the setup of the PID controller, you can select the cycle time or "period" for the controller.  So you can choose a short enough cycle time that the heating element doesn't cycle noticeably in its temperature.  So the heat can be just as smooth and "continuous" as with a dimmer (which, remember, also switches the power to the element on and off - just very quickly so that it appears to be continuous).

In many PID controllers, choosing the cycle period is part of tuning the control just as the P, I, and D terms are.  PID loop tuning is an interesting subject to say the least!  :)


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## Atl1530 (Jun 26, 2019)

daveomak said:


> View attachment 399068
> 
> 
> View attachment 399069
> ...


 I think I can figure this out. The only problem is I have two black braided wires. The one I should use is the neutral black braided wire? Please look at the attachment. Is that the correct black braided wire? 

Thank you


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## Atl1530 (Jun 26, 2019)

daveomak said:


> View attachment 399068
> 
> 
> View attachment 399069
> ...


Also, the controller you are using is not that same as the one you posted a link for.

Will this one work?


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## JC in GB (Jun 26, 2019)

Sigmo a good post with lots of technical information.  I will agree that the thermal time constant of a resistive heating element should be slow enough that on-off control should still provide tight regulation.

One thing I would like to add about using thyristors for power control.  A thyristor device has what is called a latch and hold current.  The latch current is the minimum current that can pass through the thryistor device to put it into the conducting state.  The hold current is the minimum current needed to keep the thyristor conducting.  Latch current is always higher than hold current.

In most cases, this is not an issue to an end user as current through the device usually exceeds these thresholds.  In the case of a high power controller with a high resistance load, this can cause the thyristor to shut off in the event of line dips or very low conduction.

I have this issue sometimes with LED lights.  Although they can work with light dimmers, at low conduction angles, the lights will simply go out because the lack of hold current.

All this aside.  If I was modifying this cabinet, I wouldn't bother with a phase controller as a PID will provide tight enough control.

After adding the PID, I would then add a smoke generator modification to make smoke and temperature independent controls.  Using a phase controlled heater for generating smoke might be an interesting idea though.

Anyone interested in the $20 PID controller feel free to message me and I will get you pointed in the right direction.


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## sigmo (Jun 26, 2019)

Yep.  I've had the same issues when using LED lamps with a typical dimmer.  It's hard to get them adjusted to be on at low values to begin with, and then a power dip may switch them completely off, and they don't re-start until you manually increase the phase angle to be above the required threshold.

One additional issue that contributes to this problem is that the timing of the typical inexpensive (three component) DIAC-resistor-capacitor circuit feeding the gates of the TRIACs or SCRs is dependent on the mains voltage because the trigger current for the thyristors can't be achieved until there's some fairly substantial voltage available from the mains waveform.

And that also means that with these cheap triggering circuits, you can't actually even trigger the thyristor until substantially well into the voltage waveform for each half-cycle.

When you're running things on the "hairy edge", any dip in the mains voltage may well prevent the crudely-developed trigger voltage (and current) from being high enough to trigger the thyristor.

To really trigger the thyristors reliably over the full phase range would require a more expensive circuit that stored some of the mains power to operate the trigger circuit even when the mains cycle is at or near zero voltage.  Basically, a small power supply to run the timing/triggering circuit.  And then you could have a timing circuit that could provide trigger pulses anywhere in the half cycle.

These dimmers are really inexpensive, so the manufacturers don't bother.  They figure it's OK make the first part of each half-cycle unavailable for the sake of simplicity.

Even incandescent bulbs will do the same thing on a dimmer.  If you set them down to a low setting, they'll often switch completely off if the line voltage dips.  And because of the crude trigger circuit, the brightness of the bulb, when you're operating at low conduction angles, will vary considerably as the line voltage changes.  The variation in line voltage produces an effective phase angle shift in the triggering waveform.  A dimly adjusted lamp on a typical dimmer circuit acts as a very sensitive indicator of even small drops in the line voltage.

I think they could make a dimmer with the better phase control circuit for a few bucks more, but people wouldn't really understand the advantage when they were at the store shopping, so they'd choose the cheaper units, and then the fancy good ones would likely fail to sell well.  They'd probably be less reliable, too.  Oh well! :)

The other thing I always noticed when using incandescent bulbs on a dimmer was that at certain settings, and with particular bulbs, the filament (or its support structure) would "ring" audibly, especially at low settings.

I've thought this was due to thermal expansion and contraction exciting some mechanical resonance due to the tiny filament heating and cooling in 1/120th of a second.

But I suppose it could also be a magnetic effect depending on what the structure inside of the bulb is made from.

It was actually annoying enough that we didn't like running the bulbs too low in certain rooms.  You could usually "tune" the setting to stop the ringing without too much adjustment.  It would be interesting to analyze exactly what was going on to cause this sound.


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## johnmeyer (Jun 26, 2019)

You are getting an amazing amount of really good advice. However, if you need to see more diagrams, or see how others have done this same thing (replace the MES controller), here are some links you should click on and skim through:

Auber controller added to my MES 30

MES Gen 1 and Gen @ Control Panel wiring

MES 30 DIY PID Controller Help

and this epically long thread:

MES Rewire Simple Guide - No Back Removal Needed!!!


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## Atl1530 (Jun 26, 2019)

Thank you! Thank you! Thank you! I never have much luck with the search tool


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## tallbm (Jun 27, 2019)

Atl1530 said:


> I think I can figure this out. The only problem is I have two black braided wires. The one I should use is the neutral black braided wire? Please look at the attachment. Is that the correct black braided wire?
> 
> Thank you
> 
> ...



The one of the braided black wires is the braided neutral, the other is the braided hot.

You would splice together the braided neutral to the smooth white neutral from the plug (you didn't put an arrow to it but the smooth white neutral wire is in the picture).
Then you would splice the braided hot wire to the smooth black hot wire from the plug.  Done!

NOW, you can technically splice without knowing which braided black wire is the neutral and which braided wire is the hot.  I don't believe the heating element cares.
If you want to wire it the way Masterbuilt had it configured then the braided wire that runs from the circuit board straight to the heating element is the braided neutral.
The other is the braided hot wire.   
Splice neutral to neutral, hot to hot.

How do you figure this out.... if you want to go through trouble?
Use or buy a simple multimeter that has the "Continuity" feature that buzzes/beeps/sounds like this one here (you might find for cheaper in store):


Take the panel off the back of the MES where the heating element is
*Unhook the connectors to the heating element*, do NOT leave them hooked up when attempting this test or you will get false results (have some of these EXACT MODEL stainless steel high temp connectors on hand because it is likely the connectors will fall apart or be damaged at the heating element because Masterbuilt uses junky ones to begin with)


If you have a panel for the safety rollout limit switch then open that panel (back of MES midway up, could be center or right hand side but definitely about midway up).  
If you DONT have a panel then you would need to remove the back of the MES and when doing so I would strongly suggest making a panel for the future because the connector on the safety rollout limit switch is one of the major failure points... again Masterbuilt uses crappy connectors that rot easily/quickly :(

Unhook the braided wire connectors at the circuit board
Use the Multimeter on the Continuity setting and put one tester prong into the braided wire's connector (always touching the connector metal) and touch the OTHER tester prong to the *bottom connector* of the safety rollout limit switch.  
If the multimeter beeps then you have found the braided wire that is the HOT braided wire on the circuit board.  LABEL THAT WIRE IMMEDIATELY lol!!!!
If the multimeter does NOT beep then try the OTHER braided wire at the circuit board by putting the prong in it's connector and make sure the prongs are always touching the metal of the connector.  It should beep and that would be the braided HOT wire, so label it.


Now that you have found braided HOT wire at the circuit board the other braided wire at the circuit board is the neutral, label it.
*Time to find the braided Neutral and Hot wires at the heating element.*
Put one of the Multimeter test prongs into the braided Neutral wire at the circuit board
Put the OTHER test prong into the connector of one of the braded wires at the Heating element and makes sure both prongs are touching the connector metal at all time
With the continuity setting on multimeter you should hear a beep if the braided wire at the heating element is the same wire as the braided wire at the circuit board.
If there is no beep then switch the testing prong at the heating element side to the OTHER braided wire and you should hear a beep.  Label that braided wire as the Neutral braided wire at the heating element side, and the other as the HOT braided wire at the heating element side

Splice Hot to Hot and Neutral to Neutral.  All done.
BTW I cover all of this in detail with MES pictures and everything in the thread:https://www.smokingmeatforums.com/threads/mes-rewire-simple-guide-no-back-removal-needed.267069/

Feel free to check it out and best of luck! :)


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## Atl1530 (Jun 27, 2019)

Yes Thank you. I was double checking because the two braided BK wires, on my smoker originate from the same location. Thanks for the verification


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## tallbm (Jun 27, 2019)

Atl1530 said:


> Yes Thank you. I was double checking because the two braided BK wires, on my smoker originate from the same location. Thanks for the verification



No problem :)


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