Circuit board guys please read this...

[BrentRadio]

Hey guys, this is off topic but I wanted to tap your experience on this. I have a clock that also shows the temperature. For some reason the temperature is not working right. I have replaced the battery, and I also see a bad cap and what looks like a burnt chip. I will be replacing those. I was wondering where the temperature sensor is on this board?

http://www.brentradio.com/images/Other/Build/clock1.JPG

http://www.brentradio.com/images/Other/Build/clock2.JPG

http://www.brentradio.com/images/Other/Build/clock3.JPG

Can you point me too it?

Thanks,

Brent

[drawfull]

I can't see one; I would assume it uses either a thermistor, or an LM35 device. Which is basically a temp sensor.

I assume the 106 7-segment display to the right is the temp in your pic, and there's nothing around there that I can see that would do the job. There is a transistor looking thing towards the left hand side at the bottom which could be a TO-202 LM35. Look for a component that has LM35 on it. Also, it might be the 8-pin IC in between the 21 and MON 7-seg displays.

[BrentRadio]

Yes the temp is all the way on the right, it will stay on 106, it will move around but usually ends up staying on 106 or close to it.

The cap that is blown out is a 470uf 25v
The chip that looks burnt is a L7805CV

Both of those are connected and the traces run all the way over to the temperature on the right, so I'm thinking they have something to do with it.

I also just found a trace coming from both of those above that is damaged.

[drawfull]

I think it will likely work when you've fixed the obvious faults. The chip is just a voltage regulator.