OK, not quite so lucky, the main board now has all new tantalums fitted and was in excellent condition after a little soot removal.
However, the bad news, the DC-DC converter is quite badly damaged, there are some broken tracks within the inner layers of the PCB, I think this is because the thru-hole plating has been damaged in a repair attempt at some point in the past, does any one have a schematic, a spare (not necessarily working) board I could borrow to draw the schematic from or, perhaps even better, a cheap, untouched replacement PSU, working or not? On Fri, 3 May 2019 at 19:29, Clint Jay <[email protected]> wrote: > I've just laid my hands on a Datum PRS-50 Cesium reference which 'released > the magic smoke'. > A common problem with these is the capacitors in the main PSU but these > have already been replaced by the previous owner. > > Unfortunately when he powered it up there was smoke released. > > I *think* I've located the source of the smoke and it looks like I may > have been very lucky indeed as the only burned part I can find is a 1uF > tantalum capacitor across a power rail on the main 'logic' board so I've > ordered replacements for all of the tantalums I can find, including the 2 > 47uF ones near the CS6158 Line drivers and will replace them all before I > attempt to power it up fully. > > None of the SMD work or clean up holds any fear for me with the exception > of the single 1uF tantalum that's in the conformally coated section of the > board near the Burr Brown PCM54HP, the remoival and replacement should be > fine but I am worried I might disturb something critical or upset some > finely tuned parameter? > > I'm also wondering about testing the main PSU 'out of circuit', I can load > it all up, that's fairly easy but is there any reference to what voltages > it generates and if there are any test points? > > -- > Clint. M0UAW IO83 > > *No trees were harmed in the sending of this mail. However, a large number > of electrons were greatly inconvenienced.* > > -- Clint. M0UAW IO83 *No trees were harmed in the sending of this mail. However, a large number of electrons were greatly inconvenienced.* _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
