The quick versions :
Does anyone know of a book or website which gives brief characteristics
of zemer diodes?
The ones we use in Europe tend to have the zener voltage given as a suffix
to the part number, but the US ones have 1Nxxxx numbers which tell me
very little.
The actual device I am looking for info on is a 1N5365 , but knowing
where to look in future would be useful.
The long version :
I've got an HP2631 printer (wide carriage dot matrix with an HPIB
interface). When I extracted it from my junk pile, it gave a power-on
error (according to the service manual on
hpmuseum.net) that was a RAM
error. After pulling the case and CPU board, I was amused to see the RAMs
were our old friends, 2114s. So I desoldered the RAM that the error code
said had failed and fitted a new one.
Next time I ppowered on, all hell broke loose. The carriage rammed into
the right side plate and the carriage motor breaker tripped. Then the 2
fuses on the PSU board for the +/-20V rails blew, and the status LEDs for
the +/-12V regulated supply rails went out. THe last is not too
suprising, those rails are regualted down from the 20V ones. Replacement
fuses blew at swtich-on
Quick checks have indicated that both carriage motor drive transsitors (a
2N5844 and a 2N5886) are shorted all ways round. So is the overvoltage
protection zneer between the -20V line and ground -- this is the 1N5365 I
mentioned. I obviosuly need to replace these parts -- after finding out
what caused the transistors to fail.
-tony