3 Oct
2015
3 Oct
'15
9:10 p.m.
Did you only replace those small green Nichicon parts?
If so, I would
inspect/test the others as well. My experience with these type of early mixed
SMD/through-hole boards is that some companies tried to reflow them with the
small electrolytics already in place which would damage their seals and cause
them to leak as they aged. It doesn't seem to be specific to any particular
brand/series either as I've seen Nichicon, Nippon, Panasonic, etc all
affected by this.
I only replaced the one style that was leaking on the mainboard, there is
also a bunch of others I think that are smaller.
On the driver board that runs the LCD I recapped it as well. I'll go back
and look at the smaller caps. I put the oscope on the power lines and
didn't see crazy ripple, but I only used an analog 20mhz tektronix not the
crazy heavy old HP thing with the high frequency.
If a new set of BIOS EPROMs doesn't fix it, it
might be time to look into an
in circuit emulator for the 80286. PODs for LCC sockets do exist, although
they might be harder to find than a POD for the PLCC or PGA versions.
Hmmm that would be cool :-)
Hopefully it doesn't get to that though.
--
Ethan O'Toole