Electronics > Repair
Fridge control board repair and capacitor identification help
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nbd:
Hello

I know this might be a bit of a long shot, but I saw that users in this forum helped with identifying other miscellaneous electronics, so I figured I'd give it a shot.

I have a fridge that just died, it lived a fairly long life and just ran out of life last night, no life what-so-ever. Mains power going into to the control board using a voltage detector, and that's about as far as it got.

I examined the board and found the VIper12A IC seems to have damaged itself, with a blowout next to one of the source pins, there is also a ceramic disc capacitor that connects the source pins and the FB pin of the Viper; it was leaning over against the Viper IC and seems to be sorched pretty badly (completely obscuring any text on it). I'm not entirely sure if the capacitor is damaged internally, or just scorched I only see surface marks on it, no cavities; so it might just be the VIper?

So my 2 questions are:
Can anyone help identify the capacitor? C41 on the PCB.
and, is just replacing the viper viable? (or is the failure in the viper caused from something else/ the capacitor almost surely damaged too)

I've included some photos below that should hopefully show a lot more than I am capable of explaining. I tried searching around but didn't have much luck finding anything online. This is the PCB in question (P/N B810195-410Q) : https://m.bigwarehouse.com.au/haier-refrigerator-htmr575wh-power-contoller-p-1788138.html?cPath=81300_99335_101935

Again I know it's a long shot, but I hope someone here might magically know something that can help.

side note: first time posting - haven't used a forum since I was small person, so apologies if I make a mistake or post in the sub forum
CaptDon:
What are the chances of finding a new control board? If you repair the old board you must get all of the carbonized crud off of the board since it is highly conductive and may arc or burn. If there was no local power surge or lightening in the area when the unit died then it is possible the SMPS transformer with the red tape body developed a shorted turn and caused the I.C. to burn out. Replacing the I.C. wouldn't help in that case.
wraper:
That capacitor most likely is OK, just needs some cleaning. Also you need to replace 2 nearby electrolytic capacitors. Even if they're working so far, they received a lot of beating due to high heat that darkened the board.
wraper:

--- Quote from: CaptDon on November 05, 2024, 01:21:58 pm ---What are the chances of finding a new control board? If you repair the old board you must get all of the carbonized crud off of the board since it is highly conductive and may arc or burn.

--- End quote ---
Does not look carbonized, just darkened PCB due to prolonged heating. Just replacing bad components and cleaning PCB from magic smoke should be fine.
Common mode choke (T2) looks fried too but it can be easily replaced with off the shelf part or even 2 jumpers (for testing or if you don't care about EMC).
timeandfrequency:
Hello nbd,

It looks not that bad. Maybe you can give it a try.
The good quality pictures you provided are of great help to give you a piece of advice.

Clean the board with isopropyl alcohol (denaturated alcohol is OK too) by using an old bent toothbrush.
Dry the board in sunny weather (or in your kitchen klin : 50°C   30 minutes)
As other members stated above, change all of the electrolytic capacitors (C36, C37, and C39) and verify the 4 diodes (D9, D10, D12, D13). Check the F1 fuse.
Viper of course must be replaced too. You might use a DIL-8 quality socket.

Once the parts replaced, proceed as follows :
- Disconnect the hermetic compressor.
- Then, on the mains side, connect an incandescent bulb 25 W, 40 W should do too  (120 VAC or 240 VAC depending your mains) in SERIES with the board  (towards the white mains connector).
- If the bulb lights firmly, there's still a short.
- If the bulb just flashes and then glows weakly, your board is probably repaired. Viper's low output voltage should be checked with a multimeter.

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