Faulty board from an electric heater

Thread Starter

tpny

Joined May 6, 2012
216
Hi, please see attached picture. This came from my electric heater. The lcd display doesn't come on. The 110VAC is available and goes into the board you see and out to another board to convert to 5 and 12 vdc which gets wired back to the mainboard in picture. So I see the 5 and 12vdc and 110vac available on the mainboard, but the lcd doesn't light up and the nothing is ON. Any suggestion where to check? For lack of better knowledge I tend to first blame the caps, could these big yellow square caps (3 in the picture) be faulty? They read 0.1uF 275VAC.. Thanks
 

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Meixner

Joined Sep 26, 2011
117
In the lower left corner of the photo near the fuse there is "7805" marked on the board. Check around it for voltage. Be careful if the heater does not have a power transformer.
 

Thread Starter

tpny

Joined May 6, 2012
216
In the lower left corner of the photo near the fuse there is "7805" marked on the board. Check around it for voltage. Be careful if the heater does not have a power transformer.
That 3 pin connector has 12vdc, gnd, 5vdc reading. So I"m good. There's no 7805 on the board, there is a marking though.
 

Thread Starter

tpny

Joined May 6, 2012
216
You need to check the voltages on the 28pin chip, see if its got 5v on it, that will be the problem.
5vdc is available on the board, I didn't measure on the mcu side but I'm sure power gets traced to it. I suspect the mcu (is that what it is?) is fried. If that's the case, nothing I can do to but to replace the whole heater. Why do I hate mcu's on cheap appliances.
 

inwo

Joined Nov 7, 2013
2,419
Is this a space heater?

All these fancy super efficient space heaters from ads.:rolleyes:

Show me an electric heater that's not near 100% efficient.:)
 
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