14 Nov
2010
14 Nov
'10
12:24 p.m.
I have a critical ( late 80's microprocessor controlled ) piece of test gear
no longer supported. The power supply is dead and after sawing through it's
exoskeleton I was meet with a large epoxy block the size of the original
box. I don't intend to fix said power supply but rather to figure out what
voltages it provided and use a modern switcher. I know I need +12 and +5 as
there is a generic floppy drive and the logic / processor uses +5. Any ideas
how to strip the epoxy other than digging through it with implements of mass
destruction ? Any and all help is appreciated.
Itmight be easier to work out what the PSU needs to be than to dismantle
the origianl one.
Firstly, what is the instrument (People here have some amazing stuff, and
ity's possible somebody else has the same unit and can measure the output
voltages.
If not, then how many output wires are there? Presumably there are 3 for
the ground, +5V and +12V supplies. Is there a -12V (e.g. for an RS232
port) that you could identify?
What about the analogue side? This may well need a floating supply (that
is, one with a semarate ground rail, not the same as the logic supply
ground). Op=amps (if there are any) are likely to use something like a
+/-15V supply.
-tony