Re: (Weston) Schlumberger 1240 multimeter
Manual has arrived. I haven't compared the schematic diagram with 1242 or Heathkit devices because I want to get it working again first.
I recapped the PSU (3 electrolytics and one non polarized) and nothing has changed: it starts counting backwards. There's still a bit of ripple on 12V rails, about 50mV peak: it is worth trying to tame it any further? Or rectifying diodes?
I'm wondering what are made of the two long yellow capacitors (one is parallel to the rotary switch, another near an electrolytic - now replaced -) and if they're likely to fail. The yellow one near the rotary switch is part of the dual slope integrator, it is The Capacitor doing all the job.
Rather than unsoldering one lead to isolate the component, where possible I'd cut in half the reachable lead, measure and rejoin the lead with solder. The PCB doesn't seem to be too sensitive to re-heating, but better not take risks.
Paolo
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