For this pattern generator I need the dump of the main prom (D313). It's
a
27C256 with PLCC32 housing in a socket, located in the right corner on
the
back of the instrument. Can anybody help me?

What's wrong with the one currently in it? Have you tried reading the
data
from it with a lowered VCC?

I can read it, but databit 6 is always '1' the pin is shorted to Vcc,

Ouch. Well, reading an EPROM at a lower VCC will sometimes allow you to
get all the data off a flaky device, but in your case, it probably won't
help. Did you actually measure the short right at the pin with a DMM, or
just assume it was shorted to VCC from the data pattern?

It measures under 25 ohms, so no luck there, the prom is fried anyway, it
gets warm and consumes
too much power. It's a wonder I can read it at all, but without bit 6 it is
no good.

If I had one, I'd be willing to read the binary for you. You could try
these groups, lots of very helpful folks the

http://tech.groups.yahoo.com/group/TekScopes/
http://tech.groups.yahoo.com/group/h...ent_equipment/
http://tech.groups.yahoo.com/group/Fluke_DMM/

If anyone on those lists have a PM5418, I'm sure they be willing to get
you a copy. You could also try Fluke, the last time I dealt with them they
were pretty helpful.

Good luck.

Thanks!