Adrian Graham wrote:
On 31/01/2011 21:24, "Tony Duell" <ard at
p850ug1.demon.co.uk> wrote:
You have removed the seires bulb now, I hope. I
doubt the machine would
run with a bulb in seires with it.
OK, I've removed the bulb and checked the voltages on the floppy connector,
seems like the death of the 12V circuit is what caused the mains fuse to go.
+5V is reading +6.2 and +12V is dead. Looks like I'll finally have to remove
the PSU from the case which will be fun as the earthing screws on the rear
of the case have corroded quite badly.
Anyone got a schematic for the PSU?
I don't remember it being too complex - i.e. "traceable in ten minutes"
level
of complexity. If the screws are just for earthed terminals via wires,
worst-case you could always cut them close to the terminal end and re-solder
them afterwards, I expect. I've never seen the schematic in any of the RML
manuals.
+6.2V on the +5V rail is worrying - hopefully just an unloaded reading; if it
really is that much it may have caused a mess (although I managed to
accidentally stick +9V into an Atom that was expecting +5V once and incredibly
it survived)
+12V is used by many of the boards (as is -12V, although usually not directly,
but via 7905 regulators to get -5V), so you're not going to get anything
without +12V running.
cheers
Jules