Quadtech 1880 Milliohm eter calibration procedure

[BobBeBob]

Hi, any luck getting a few more pictures from the back of the PCB please?

[BobBeBob]

Hi There,
any luck with those pictures please?

[BobBeBob]

Hi it's me again, sorry to bother you. But I was wondering if you would send me a few more pictures from the back of the board of the quadtech 1880 please. pretty please.
I have a picture here from you but I need more to the right of the board. the pictures you send are is very nice and clear but I wish I had some more images of the back.
I am attaching some thermal images of my board which indicate a short I think on U29, which on yours is a OP77EP, But on mine is a LTC1052CN8. I have a 0P77 on order and will be replacing and will look for any change.
Also below chip U31 is a resister I want to guess is R51, (the number is under the piece and not able to read it), on one side the resister traces out to U30 pin 5. well, there is what appears to be a Zener Diode next to it. I want to know if the resister and the cathode side of the zener diode are connected in the back of the board. this is one of the reasons I need more pictures of the back of the board please.

[BobBeBob]

Hi, so I seem to found a short on U29, which is a OP77EP on you board but on mine is something else. I attached thermal images for viewing. ordred the OP77EP, we will see what happens.
I could use some more pic from the back of the board.
one reason I need more pictures is because I need to see if the resister in below chip U31 which one side of it traces out to pin 5 of chip U30, is connected to the zener diode cathode side. it looks as if the trace on mine was scrapped off in the back. 

[BobBeBob]

more thermal pics

[BobBeBob]

more thermal pics

[BobBeBob]

 279 F. I think the measurement is within 0.2 C accurate. but as soon as I took U1 chip out of socket the heat went away and the rest of the chips turned on with normal on.

[BobBeBob]

After undoing the birds nest and soldering several cut traces. I think I did it correctly. though not sure if the cathode of zener diode next to R53 is connected to it or not. I connected it. Ran out of patience, crossed my fingers, plugged the unit in and turned it on. No sparks but, It was still not making any measurement. it was stuck on 4.232 M ohm. it was stuck on that number in every range but decimal was moving. before undoing the birds nest the unit was stuck on 5.5xx M ohm, That's when I decided to get the short finder for dummies out, the thermal camera. I was not looking for a short but just wanted to see what is on. And yes, there was a short there. But, unfortunately, I did not take a before thermal picture. So, I don't know if removing the birds nest and connecting R53 to the cathode of the zener next to it caused this issue or was it this way before.   If anyone has picture of the back side of the board I would appreciate it if you could send some clear pictures of the backside of the board of quadtech 1880. thanks.

Bob
 

[BobBeBob]

sorry everyone for multiple posting the same. I just figured out there are other pages to the threads. figuring out EEVblog is like the first day driving on the opposite side.

[BobBeBob]

Ok, my apologies, I think I made a few mistake, let me just make a quick correction.
U29 I think is the chip that has the short, it is OP77EP. 
R51 it appear to be the resister that I would like to see if it is connected to cathode of the the zener diode next to it. these 2 are next to U31 pin 1.
any info is helpful

thanks
Bob