Datron 1062 LS101 DMM AC Board WTF

[Johnny10]

I am working on a Datron 1062A DMM and the AC function is not working so I take off the shield around the relays and WTF the relay is not wired.

Doesn't have any solder on connections?

[tsman]

Looks like somebody has been in there before you and swapped out the relay but never soldered back the wires. The wires look like they've had solder at some point. The sticker is peeling up on the replaced relay.

[coromonadalix]

maybe he / she forgot the wiring connections and could not put it back correctly 

[Johnny10]

I am wondering if that might not be true.

[dacman]

That's the AC+DC relay.  It either routes through or bypasses the yellow capacitor.  I would suggest wiring the power and checking contact resistance when both energized and deenergized.  Power for the coil comes from the pin that looks like a stub in front of it in a similar configuration as the other relay.

According to the schematic:
1) RL2 Pin 10 (Right Relay Bottom Left Pin) goes to RL3 Pin 9 (Left Relay Inner Middle Pin)
2) RL3 Pin 8 (Bottom Center Pin) goes to the junction of R164 (470 Ohm) and R165 (100 kOhm)
3) RL3 Pin 7 (Upper Left Pin) goes to the junction of R165 and R166 (560 Ohm)
4) RL3 Pin 10 (Lower Left Pin) goes to the other side of R166
5) RL3 Pin 6 (Left Middle Pin) goes to the wire to the left of the yellow capacitor (junction of C77, C78, C79, and R167)
6) RL3 Pin 5 is not connected

If you do not have the manual, it is available at http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=06_Misc_Test_Equipment/Datron
It's the one with a size of 80M.  I purposefully did not directly link it (some webmasters do not like their files directly linked).

[Johnny10]

Not very good connections on those relays.
While examining the second relay a couple of wires fell off.

And I was gentile, I promise.

[DC1MC]

Sadly, the death of many Datrons it's the acid flux that was used for soldering   . It gave us nice instruments cheap but the price is fighting with solder, sockets and corroded wires.

DC1MC

[Gyro]

To be fair, the acid flux problem has only been found in very specific instances (and I think date range) - the soldering of the TO3 pkg regulator at the back of a few similar age 106x meters is the only one that comes to mind (posibly a single assembler with the wrong reel). Generally the flux used is standard rosin and the boards well cleaned.

I suspect that the wires falling off the second relay is more likely to be due to whoever was in there before you already having repeatedly flexed the wires, the joints already made brittle by solder wicking up wire strands (a particular problem if those wires are silver plated, teflon insulated).

[Johnny10]

OK
I connected the new Relay.
And look at that nice stable output on the integrator.

Changed the usual M1
All electrolytics.
Have 15.01 and -15.01
6.42 and -6.45 Reference
5.10 on the 5 volt line

Only one problem left to manage...
the -15V line is not always 15V sometimes on turn on it is -13.5 +-
Repeated on-off cycling and I get my -15.01 back.
When it is -15.01 it is stable until I cycle power switch.
Same when it is 13.5

Only thing I can think it might be now is that tantalum I haven't changed C11.

Guess I should work on that after lunch.