25 pdvc questions

[slvrblkk]

I guess just for sh!ts and giggles you can try and put the board in "C" mode and see if it would by chance work.

 

[Chrisnow86]

Sounds like the relay for the cycle times is shot.. Idk if a mode change would do anything..

 

[Harvey Schneider]

Sounds like the relay for the cycle times is shot.. Idk if a mode change would do anything..

There is no relay. The motor is controlled by a triac on the circuit board. The motor runs when in diagnostic mode but receives no power in run mode.

 

[Chrisnow86]

Then what should he do? New control board? Sounds like his only option at this point... Idk about fixing it..

 

[slvrblkk]

Probably, unless he is savy with a soldering iron.....

 

[Chrisnow86]

I would need a few drinks in me to have the courage to complete that task!

 

[Jason Knapp]

There is no relay. The motor is controlled by a triac on the circuit board. The motor runs when in diagnostic mode but receives no power in run mode.

Can you explain what a triac is?
For the $217, I may just get a new board, rather than chance a repair from someone on ebay.
Before that, I'll go to "c" mode and see what happens. I won't run it in that mode, I'll use it to see if it straightens out.

 

[Harvey Schneider]

Can you explain what a triac is?
For the $217, I may just get a new board, rather than chance a repair from someone on ebay.
Before that, I'll go to "c" mode and see what happens. I won't run it in that mode, I'll use it to see if it straightens out.

A triac is a semiconductor switch. It gets switched on by a signal from the microcontroller on it's gate and stays on until the AC on its main terminals drop to near zero. It can be used to provide a proportion of the AC waveform for speed control or for simple switching. Light dimmers use triacs.
The triac on your board is obviously working since diagnostic mode was able to turn it on and drive the motor.
It still puzzles me that the motor runs in diagnostic mode but not in normal mode.

 

[slvrblkk]

Can you explain what a triac is?
For the $217, I may just get a new board, rather than chance a repair from someone on ebay.
Before that, I'll go to "c" mode and see what happens. I won't run it in that mode, I'll use it to see if it straightens out.

Can you take a close up pic of the whole board? If it's too much of a pain don't worry about it.

 

[Jason Knapp]

I certainly can take a pic tomorrow. I got into the moonshine a little bit tonight. Walking to the garage may not be an option!

 

[Jason Knapp]

A triac is a semiconductor switch. It gets switched on by a signal from the microcontroller on it's gate and stays on until the AC on its main terminals drop to near zero. It can be used to provide a proportion of the AC waveform for speed control or for simple switching. Light dimmers use triacs.
The triac on your board is obviously working since diagnostic mode was able to turn it on and drive the motor.
It still puzzles me that the motor runs in diagnostic mode but not in normal mode.

I agree its strange......... I wish I knew why it's acting so strange. I'll tinker a bit more with it tomorrow. Maybe another reset will help. What gets me is, the room air blower comes on within 30 seconds of hitting the start button. The blower also doesnt seem to reach any faster speed than 3. Maybe the board took a hit from an electrical surge?

 

[Harvey Schneider]

I agree its strange......... I wish I knew why it's acting so strange. I'll tinker a bit more with it tomorrow. Maybe another reset will help. What gets me is, the room air blower comes on within 30 seconds of hitting the start button. The blower also doesnt seem to reach any faster speed than 3. Maybe the board took a hit from an electrical surge?

Try lifting the proof of fire thermocouple from the chassis. You might have a line voltage leak to the chassis that is driving the logic crazy.

edit
Don't do it until after your buzz wears off.

 

[CladMaster]

Hmmm ! I have an idea, and it's a long shot !

Remove the power from the stove.

Take pictures of the back of the control board showing where all the wires are connected.

Remove the control board from the stove.

Check all the connectors to the control board. Pull them and reconnect.

The digital display and buttons are on a separate board and are connected to the control board via a ribbon cable, check this too.

Under this ribbon cable is a chip, it's not soldered to the board, it sits in a special holder so that it can be removed and replace with a different chip. Check that this chip is seated in it's holder, do not remove it from the holder, the pins on these chips can break if mis-handled.

 

[Jason Knapp]

Try lifting the proof of fire thermocouple from the chassis. You might have a line voltage leak to the chassis that is driving the logic crazy.

edit
Don't do it until after your buzz wears off.

I'll do this today, sober... The thermocouple is the copper terminal that's fastened to the rear of the firebox, correct?

 

[slvrblkk]

I'll do this today, sober... The thermocouple is the copper terminal that's fastened to the rear of the firebox, correct?

Correct.

 

[Jason Knapp]

Hmmm ! I have an idea, and it's a long shot !

Remove the power from the stove.

Take pictures of the back of the control board showing where all the wires are connected.

Remove the control board from the stove.

Check all the connectors to the control board. Pull them and reconnect.

The digital display and buttons are on a separate board and are connected to the control board via a ribbon cable, check this too.

Under this ribbon cable is a chip, it's not soldered to the board, it sits in a special holder so that it can be removed and replace with a different chip. Check that this chip is seated in it's holder, do not remove it from the holder, the pins on these chips can break if mis-handled.

I'll do this too. Should I be looking for signs of corrosion? Obviously I'll check the board for any burn marks and terminal condition as well.

 

[slvrblkk]

Here's the wiring diagram but with the hopper switch included. Probably wouldn't be a bad idea to double check and tract the wiring out.

 

[slvrblkk]

The other thing....I know you checked continuity over the vac switch but jump the wires together and take the switch completely out of the equation........UNPLUG THE STOVE BEFORE DOING THIS THOUGH.......

 

[Jason Knapp]

The other thing....I know you checked continuity over the vac switch but jump the wires together and take the switch completely out of the equation........UNPLUG THE STOVE BEFORE DOING THIS THOUGH.......

I did this yesterday. I then ran the stove but again, the upper auger motor wont move.
THANK YOU SO MUCH for the diagram. This is the second stove that you have helped me with. I greatly appreciate it.

 

[Jason Knapp]

Okay, another update. I did another board reset and tried running it in "c" mode. Still the same issue. I also removed the thermal sensor and it didn't help. I removed the board and took some pictures of it. I found corrosion on the ribbon plug. I have a suspicion that this may be my headache. I'll take the front off and see the extent of damage. I may try to gently clean everything and see where it gets me.
Here are some pics, I wish the quality was better.

 

[slvrblkk]

Is the thermostat jumper in place?

 

[Jason Knapp]

Yes, the jumper is in place.

 

[stoveguy2esw]

9 in 10 its in the chip for the board , the PROM chip is what controls the timing of the auger , the circuit (on the hardware side) appears to be intact, but the "run" mode timing is not present. you MAY be able to fix this with a replacement PROM chip instead of the whole board.

locate the PROM, its the chip thats about an inch long 1/4 inch wide (ish) has a white sticker on it that says englands pu-cb04 rev(im thinking 13) on it. this chip can be removed and replaced, i'd try removing it and carefully reseating it to see if this makes it start to behave, IMPORTANT , make sure you orient the chip in the same position as it came out as it will "fit" backwards, locate the indexing mark, its a half circle cutout at one end of the chip, when you reinsert the chip that cutout needs to be at the same end it was or nothing will work right

 

[Jason Knapp]

9 in 10 its in the chip for the board , the PROM chip is what controls the timing of the auger , the circuit (on the hardware side) appears to be intact, but the "run" mode timing is not present. you MAY be able to fix this with a replacement PROM chip instead of the whole board.

locate the PROM, its the chip thats about an inch long 1/4 inch wide (ish) has a white sticker on it that says englands pu-cb04 rev(im thinking 13) on it. this chip can be removed and replaced, i'd try removing it and carefully reseating it to see if this makes it start to behave, IMPORTANT , make sure you orient the chip in the same position as it came out as it will "fit" backwards, locate the indexing mark, its a half circle cutout at one end of the chip, when you reinsert the chip that cutout needs to be at the same end it was or nothing will work right

Thanks for the response, Mike.
Is the PROM chip available through you?
I sent my board to another PDVC owner so he could try it on his stove. If he gets the same result then at least we narrowed it down.

 

[stoveguy2esw]

yeah we have replacement prom chips, i suspect its the issue either its not seated cleanly or its faulty