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 A common problem with these is the capacitors in the main PSU but these have already been replaced by the previous owner.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.* _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.