[zqone537]

Hey all,
When I turn the power on on my lunchbox the CP4500 meter goes all the way to the left side and ossilates back and forth some. Not all the way to the right. I here a ticking noise as well. And when I press the IN button, the light blinks on and off in sync with the meter and the ticking I here.
Help Please!

Thanks!

[JPK]

Did you check the usual suspects?
And eliminate the frequent mistakes?

What is your PCB revision number?
Remove all IC's from their socket, unplug the meter and power up again.
Is it the same? If OK, re-plug everything, one at a time until you find the component causing the issue.
Double check the meter wiring.

[zqone537]

MY revision board is 1.4 Ok so unpluged the meter and took out all IC's. When I power on the Lunchbox the ossilating is not happening now but when I press the IN button I get no light. Not sure if that is good or bad? Next I then I plugged in the meter. The meter doesn't light up nor the IN button either. Not sure if that is good or bad? So plug in IC U8-(OPA2134) meter lights up no ossilating. Next U22-(OPA2134), IC U21-(OPA2134), IC U10-(OPA2134),U6-(OPA2134),IC U7-(THAT1646) good!, So now I plug in the THAT1246 and still the meter lights up. However the IN button light never came on no matter what IC I have pluged back in. Nor did it come on when everthing was unpluged at the beginning as well?? Weird!! So I don't know what the heck is going on with this thing? 

[JPK]

but when I press the IN button I get no light.

Not good.

Check the solder joints on CN2a, CN2b, D3, RLY1, R104. Look for solder bridges.
Check the direction of D3, D19 and RLY1.
Check the LED with your DMM in diode mode.

[zqone537]

Ok so I just pluged it back in. I got ossicaling again. Got the meter light still. But still no IN switch light. So I pulled all the IC's out one by one. Was still ossilating now mattter with them all in or all out. Then I notice that the resistor at R41 is smoking when all the IC's are out!, like with the ossiclaing. Smoke, no smoke, smoke, no smoke,.... It's the right resistor which is the value of 1R. This is a nightmare....What did I do wrong? 

[zqone537]

And I checked all of the diodes, Relay, and CN2B, CN2A, ans everything looks fine. And the resistor didn't smoke when all the IC's where pluged in. 
What gives?

[JPK]

R41 smoking is caused by a short circuit somewhere.
Keep all the IC's removed.
Check the short circuit with an ohmmeter between the V+ pin and ground.
Is it still present if you disconnect the front PCB?
If not, the short is on the font PCB.

[zqone537]

I removed the front PCB and the ossiclating stoped. So this means the problem is on the front PCB? If so, how to I check to see what is causing the issue? There are no test points on the PCB? The solder joints all look good. So no bad connections. Will the componets give me the same values as they would if not soldered on the PCB? 

[zqone537]

SO I checked the front PCB. I foud that R24 reads .815R. It is supposed to be a 270K resistor. So I guessing that means I put the wrong resistor there? So now I'm thinkin I should check PCB-A to find that 270K resistor? Or maybe on PCB-B? Think I'm starting to get the hang of this. Let me know if I'm on the right track here JPK.
Thanks man! 

[JPK]

I foud that R24 reads .815R

Set the attack to 30 and redo the test. It should read good.

Replug the front PCB but unplug the meter. Does it work?