# circuit board repair



## Rick31797 (Apr 20, 2007)

Does anybody know a good place to have a circuit board looked at and repair if needed.. This is not out of an amp, but out of a pellet stove..I didn't want to post it here, but thought maybe i could get some help as there is no, new replacement board, and i would like to try and get it fixed. I don't know much about things like this..but it is the last part to replace, so i am sure there must be a part gone on the board, if you can help that would be great.Thanks.


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## keto (May 23, 2006)

Dig around google and see if you can come up with the schematic. From their, any amp tech or electronics repair shop can look at it for you.


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## Rick31797 (Apr 20, 2007)

I do have the manual and schematic, i guess what i am thinking , can a amp tech repair other boards besides from an amplifier...they look all the same to me..this board runs 12 volt motors.


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## jb welder (Sep 14, 2010)

It is possible an electronic or amp technician may be able to fix it. Does the company not offer board repair rather than replacement?
Please post make, model, fault symptom and post schematic if you can.


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## Rick31797 (Apr 20, 2007)

OK SORRY, dont have the schematic, this is what i have , no the company has no repair, there service is terrible since they were bought out..

its a thelin parlour 3000 , it is 12 yrs old.. this stove runs naturally on 12 volt..it has a transformer in it that changes the volts from 120 to 12 volt.it is also manual start.Turning the stove to fan, to start it, the motor runs very slow, not fast enough to cause enough air to lit the stove., not the motor , i have a new one , and the one that is in it has less then 10 bags of pellets through it.Only two sensors in this stove both replaced. Control switch also replaced..

there is a flashing green LED on the control board, i was told this means there is power going to the board.. when i turn the switch to low med and high, i hear the auger turning, but fan is still going slow.. on the clean setting fan goes fast, i would say normal..
I have check all fuses...the only thing that is left is the board..the board is small 7 inches by 4 inches


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## Fader (Mar 10, 2009)

I would swap out the 3 pin device that is bolted to the extruded aluminum heat sink.


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## Rick31797 (Apr 20, 2007)

is that a mosfet transistor, and what would be its job, being attached to a heat sink, it must have alot of current through it


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## Fader (Mar 10, 2009)

It looks like it could possibly be a 7805 variable voltage regulator.
The fan has lost speed control, that's the component that does that.
It could be something else, but if I had to guess....


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## Rick31797 (Apr 20, 2007)

it says on it 

WOP004

MOROCCO
TIP 42C


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## Fader (Mar 10, 2009)

http://www.alliedelec.com/search/pr...&pmt=b&pdv=c&gclid=CJCO5uHozbwCFckWMgodx38AKQ

That's a power transistor, it might be for the battery then. 
Follow the circuit trace from pin 13 on the back side of the control board. Where does it go to?
Towards the power transistor or Q1 and Q2.
What's the numbers on Q1 and Q2?
Do you have a volt meter and a soldering iron?
If not, you need to make friends with a tech-type person.
I can guess, but you need to do some testing to narrow it down, I don't want to lead you astray on a supposition.
Some tests may require the component removed from the board, and if you don't have the right tools, you can damage the board. 
Sorry.


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## Rick31797 (Apr 20, 2007)

I know this is difficult to diagnose...i do have a multi-metre and a ground strap and soldering gun, i would not be afraid to replace these if they are bad....

Pin 13 goes too Q1 the number on this Mosfet is 1RFZ 34N
1 R045T
7A 9 C

BOTH Q1 AND Q 5 Are the same..


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## Fader (Mar 10, 2009)

Don't go near that board with a soldering gun. It's way too hot, it can easily overheat a trace and cause it to lift and the excessive heat can damage components easily. A gun can generate a magnetic field large enough to destroy those integrated chips.
Get a 20 watt pencil, preferably ESD rated.


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## Rick31797 (Apr 20, 2007)

I have a 30 watt pencil i got from the source ...


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