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Anyone have schematics or replacement for a Samsung LS32AM702UNXZA main board (BN41-02821A). I’ve tried the regular ebay, shopjimmys..etc.. and nothing .. Schematics would be very helpful. The TV keeps cycling - voltages to main board are steady so power board is fine, problem seems to be on t-con board
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Hi @dgluck ,
Normally with Samsung TVs that have a separate tcon board, (I don’t know about monitors) there is a board mounted smd type fuse very close to the cable connector for the cable that comes from the mainboard, check if there is also power on it when the monitor is turned on.
If there is power, then tcon boards do not cause on/off cycling problems. That is usually a mainboard problem (corrupted firmware perhaps?) or a power board problem. The tcon board is used to connect the video signals sent by the mainboard, to the screen and if it is faulty then there is no display or a weird display etc rather than a cycling problem, but again this is with TVs so maybe monitors are different.
Here’s a link to the service manual that may help as it may have the schematic. Usually service manuals do.
Unfortunately, you have to purchase it but at least it is available.
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Thanks! I was starting to lean towards firmwear too -
The fuse is fine and all voltages seem to be OK on all boards. I was going the short circuit route as the CPU or main chip gets extremely HOT very quickly and on the board that is attached to the LCD panel via the thin ribbon cable has a hot spot as well on one of the ribbons. When I disconnect the lcd, the CPU doesn't get as hot - but again all the voltages on the small LCD boards all seem to have appropriate voltages. weird..
Update - I just did voltage injection on just the main board while not connted to anything and I could tell by the amp draw it was stull cycling - it would go from 6ma to nill and repeat - I could also hear a very faint auditable screatch each time it cycled... not sure - maybe fried CPU as it was extremely hot after just 1-2 min of voltage
Unfortunately the firmware can only be updated if the TV is working as you have to get to the menus to select the USB option if manually updating it.
Since you can't find a replacement mainboard, I thought an option was to maybe look for a donor monitor but as it is a gamble whether the mainboard is OK or not (read description of problem) and given its cost, getting the service manual may be the better option.
Cheers
Yea - not feeling good about this one... I've been looking everywhere for a doner board - guess this one hitting the pile until a future date :)
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I agree with jayeff, cycling is indicative of power supply or mainboard problem.
The power board is almost certainly your problem with bad/dried caps being my first check
My exp with television CPU’s is manufacturers allow them to run HOT, but do not discount thermal cycling on the CPU…
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Thanks - def not the power board - I tested all caps, isolated the CPU board, did voltage injection and still has the cycling issues - it's a weird one .. I'm moving on just wish I could find schematics on this board - I'm saying bad CPU or main chip ..
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What is the board called in the second picture?
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