Or expose enough leads of the damaged parts to check what it is and find a replacement.
If it's on the heatsink, it is probably used as a linear regulator and there will be a large section of the datasheet that you can safely ignore. On Sun, Apr 29, 2018, 7:02 AM Nigel Clarke via volt-nuts <[email protected]> wrote: > Perhaps somewhat off topic but just wondering if anybody here would have a > service manual for this instrument, or even just a schematic particularly > of the power supply section? > > I've just bought one that was totally dead on arrival and it looks to have > been blessed by the idiot's touch, both from an original mechanical design > point of view and subsequent user intervention. > > It turns out the the TO220 PSU power transistor is mounted on the back > panel and rigidly soldered to the circuit board, although I still haven't > figured out quite how they managed that in this instance, and there's > nothing to prevent removal of the back panel, even with the covers still > attached, which someone has obviously done and snapped off all three > transistor legs flush with the body. > > There's no obvious PCB damage, so it could have been a lot worse, and I > should be able to add some flexible tails to the PCB and then solder these > to the replacement transistor pins to include some future stress relief, > but this LM723 based PSU looks to be quite complex, it includes a lead acid > battery charger with overvoltage and deep discharge protection, thermal > protection too by the looks of it, and all involving another five ICs plus > associated circuitry, so some adjustment is likely to be necessary, which > is where the manufacture's instructions would be most useful. > > I guess plan B might be to expose enough of the leads on the existing > transistor to reuse that if possible, whilst hoping the original adjustment > still holds, but aside from the quite "interesting" surgery required it > would still be nice to check the adjustments anyway. > > Nigel, GM8PZR > > > > > > > > > _______________________________________________ > volt-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
