Have you every had a circuit board repaired

I would test a part before just taking the shotgun approach. as said before mouser or digikey, maybe future most of the time for my home projects I just use EBAY....they are usually cheaper with faster shipping.

Harvey Schneider said:

There is a saying
" When you hear hooves, think horses not zebras."
It is unlikely that the microcontroller is bad. It is much more likely something at the power end like one of the control transistors (MOSFET's).
The bad news is that MOSFET's are very sensitive to static electricity and simply handling them can cause permanent damage. Even pulling the board out to look at it can result in damage.
Unless you are familiar with electronics and know how to handle the components safely, you should not undertake the repair yourself.
If you have to handle the board, to ship it to a repair facility, always touch the chassis before you touch the board. That will discharge any static charge that you have acquired. The board should be wrapped in aluminum foil if you don't have an anti-static bag to put it in.
If you feel comfortable working with static sensitive components, you can get replacement parts at either Digikey or Mouser
Good luck.

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The way to work with circuit board is to wear a ground strap. One end is hook up to the chassis as mentioned and the other is put around your wrist. You can use lotion are something around your wrist to get a better connection. That's really all that is required. Yes, MOSFETs are very sensitive to ESD as they act like a lighting bolt to the device.

you can buy these directly from the manufacturer, for example, ir is IRC. they even have application support to help you understand how the product works. But what if these are perfectly fine and you replace them, it will be a waste of time.

I would get a volt-meter and do some kind of continuity test first just to make sure there isn't any shorted/open connections.

rick31797 said:

HOW DO I FIND THIS PART

IRFZ34N

I RO45T

7A 9C

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IRFZ34N is the part number.

Assembled products inc.Repair service.

rick31797 said:

I have an anti-static wrist strap, but when the board is out of the unit, what do i attach the ground to...I suppose i could put it back in the stove, but easier to check when its out..


I see alot of parts IRFZ34N , but i think i need the exact part if these are gone ..I take it 7A means 7 amps and 9 C has something to do with Temp.

I will try and test these, but i am not sure what i will be looking for. Do these resistors either work or not..or are they like The other type that have a value and can be weak..

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Don't worry about the other markings on the FET. They are usually body style and date codes or manufacturing lot numbers. Match the visual appearance of the package which appears to be a TO-220. I gave you a link directly to that at Mouser.
The ideal ground is the third prong of an electrical outlet (a banana jack fits it). A water pipe would serve just as well, but is harder to attach to.
Resistor values are unlikely to change unless they are overstressed by the design. That would usually result in discoloration of the resistor's body. The stripped lines on the resistor are a code that tells what the value is supposed to be. It is often hard to measure resistors while in the circuit because they are connected to other components that can affect the measurement.
A possibility is that the Voltage range of the motor drive is set by one of the two trim pots at the corner of the board. Trim pots are notorious for going open circuit due to contamination or vibration. It might be worthwhile to try walking the pot settings back and forth a small amount around their present setpoints to see if they have developed a dead spot. There is a paper label on top of the large black capacitor that seems to indicate that the motor Voltage range is 7.5 to 10.2V. Moving that a little to avoid a dead spot wont cause any problems. Small changes only.

I'm not sure I understand your question. One end goes to the stove, the other end go to your wrist. You and the stove should be on the same surface if possible. That way, you are all at the same potential. Any component you pull out of the stove, will be at the same potential as well. Just try not to move around and change surfaces that will change your potential and you'll be ok.

The part description is in the product data sheet. It looks like a fast switching gated diode. If you don't know what you're doing, you are not going anywhere fast. You are better off sending it out somewhere to have it checked. Even soldering is skill that shouldn't be taken for granted.

GeHmTS said:

I would get a volt-meter and do some kind of continuity test first just to make sure there isn't any shorted/open connections.

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That isn't helpful if he doesn't know what he is looking for.

wsar10 said:

I just use EBAY....they are usually cheaper with faster shipping.

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Most of the inexpensive vendors on Ebay are in China or Indonesia. Shipping time from them is usually about three to four weeks.
We are talking about $1.63 each in single piece quantities from Mouser. I realize the shipping charges are going to be more than the cost of the parts, but there really isn't much to save by going to Ebay and at least I know that the people at Mouser or Digikey will handle and package the parts correctly.

agreed, i would send it out for repair if I was him.

looking at your past posts you have had this and other motor problems since 2010.Thelin would reccomend updating the stove.There are reasons for updating.

To find which MOSFET is for the fan drive, use a multimeter, ohm scale, and measure from the board connector Pin #13 (with the cable removed from the board connector, and pin #13 is where the black wire from the fan motor is on the stove-end of the connector) to the metal tab of Q1, or Q5 The fan drive MOSFET is the one which will show continuity, or less than 2 ohms (or so).

If you don't have electronics / soldering skills, I think you have two options:
1) Shotgun it a bit : Bring it to a "TV Repair" shop and ask to have the fan MOSFETreplaced, if they won't charge you too much.
2) Search on ebay for "pellet stove board repair", there is a guy who fixes these things.

Another question : Does the feed motor seem to operate normally?

rick31797 said:

I would like to send it out for repair if i can find a company that is experience at fixing Circuit Boards ,

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http://pelletblowers.com/bbandp/product_info.php/products_id/54

I believe he also has an ebay.ca site. (Probably the same guy that Pelleting In NJ mentioned)

I sympathize with this scenario completely.

I went one better, and sat down and built my own controller using timers from the great folks at Precision timer company
Prime Technology | Timingck

I used the 644B-GR5 for the start timer and the 646B-P15RO for the cycle timer with a KPM-1M-A pot to adjust the off time (heat range/off time)

The fan speed can be adjusted using a standard TRIAC fan controller.
Use all the original snap switches, vacuum/pressure switches, door switches if equipped.
Install a fuse in the system that is the same value as the factory one.

The stove control board prices are ridiculously high and they are proprietary.

The timers referenced above are off the shelf technology mosfet units.

Set your timers to duplicate the original operating parameters and your set.

The timers are far tougher than the factory equipment.

It took me about an hour to sit and doodle out the schematic and get it ready to wire up.

You can keep a couple spare timers on the shelf for very little $$$ and on that cold night, you can swap out a failed one (if that ever happens) in a few minutes.

The timers are all spade plug in type with a single attaching screw to fasten the unit to the stove chassis

Snowy

The safety overtemp switches all need to be in the circuits, as does the low limit switch and any pressure vacuum switch and a door switch if used.

These pellet stoves are very basic wiring 101

A few years ago, the same timers I am using were standard equipment on most stoves, butttttttttttttt
the manufactures figured it out that all the needed components could be reduced in size and placed on one plug in circuit board, and they could get it done overseas for pennies and charge the end user a metric buttload for replacements.

The OEM costs on the original boards they use when building a new stove is Cheap (their cost)

You simply need to trace out the circuits and duplicate it

The draft fan, convection blower and auger motor are your basic units.

The draft fan usually can be run at line voltage (full rated motor speed)
The convection blower can easily be controlled by a triac (fan speed controller)
The timers allow the auger to feed the correct time and stay off the correct time.

Connect the overtemp snap switches to cut main power if the stove over heats.

The vacuum switch if used will stop auger feed if the door is opened

The low limit switch is set between the feed timer and feed motor and the one shot start up timer bypasses the low limit switch for a 10-30 minute start and warm up time.

Any additional heat sensitive safety switches are wired in to shut the power off if the stove overheats or if an exhaust pressure switch is used it will stop the stove if the switch opens due to a plugged chimney.

Very basic functions.

Very low cost to do it with the off the shelf timers

Snowy

Snowy Rivers said:

Connect the overtemp snap switches to cut main power if the stove over heats.

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It would be better to have the overtemp inhibit fuel feed and allow the convection blower to continue running. Originally I was thinking that it would be good to keep the combustion blower running as well, but I decided that's a bad idea. My reason for keeping the convection blower running is to cool the stove faster.

Try taking the board to a tv repair shop they may be able to put a new ribbon in the board.

for what its worth, i had a board repaired once vs buying a new one. It wasnt a pellet stove, it was an ABS board for my car. $50 for the repair. Would have been $800 for the board to DIY or $1500 for Audi to do it. I took a chance, sent the board. it came back perfectly repaired, i put it in and the board and abs outlasted the rest of the car.