UT61E multimeter AC measurement issue

[kellys_eye]

Check the tracks/traces under the rotary range selector switch and pin 21 of U1 - should be grounded under AC measurement situations.

 

[pharaon]

tracks/traces under the rotary range selector

It looks good, cleaned it but still same issue

 

[pharaon]

those are the latest update.
i cleaned VR2 with some alcohol, rotate it, the voltage changed to +350 ACV for couple of second then back to the same issue again
i replaced VR2 still same issue.
i found that D6 and D5 are shorted, took them out of circuit and they were fine. tested where they been soldered to and it's shorted . is it suppose to be shorted? i don't think so. but i'm not sure what cause that shortage.

 

[Martaine2005]

Check the capacitors. Don’t forget the SMD ones.
If one is shorted, take it off the board and check across the pads again.

 

[pharaon]

Check the capacitors. Don’t forget the SMD ones.
If one is shorted, take it off the board and check across the pads again.

which one?

 

[pharaon]

Check the capacitors. Don’t forget the SMD ones.
If one is shorted, take it off the board and check across the pads again.

i have an old multimeter same that have faulty controller. anyway i found the same diodes shorted in it as well

 

[pharaon]