EIIIXP Power Supply Issues? (Garbled screen, no boot)

[Dillon]

So I just got a unit that has the analog upgrade but had the hard drive removed. I tried to boot it up as is but it just whines. It makes a high pitch buzz, and all the lights turn on, the display shows garbage, etc. All things that made me think that it had a bad power supply. The thing is that I get +5, +12, -12 all the way to the end of the ribbon cable at the board.

Would installing a hard drive allow this to boot? Or do I have to dig deeper? I?m trying to find a schematic but no luck yet...

[Dillon]

All lights are on


Screen output is garbage


U75 has been replaced?  I should do a reflow because it?s looking spotty


U107 has has bypass cap installed? Or something... that?s not factory right?

[Dillon]

I am still wondering if this need a hard drive or some kind of scsi termination or jumper wire or something like that to run. As it is now, it only has the resistors

[lubb]

I had exactly the same trouble with my EIIIX: the culprit was an electrolyte leakage from EL capacitor(s) on the PSU... I pulled out the PSU and thoroughly cleaned all the 'wet' traces on the printed circuit board with a cotton swab moisted with isopropanol... Now it works perfectly... Of course, the best measure would be to replace all the old EL capacitors...

[OB8]

You need a jumper on one or the other of those termination pins. I'm sure in either the owners or service manual the correct process is detailed.

You may still have more problems than that in addition.

Good luck

[lubb]

These two jumpers are for applying termination power to the SCSI bus. All EIIIXs were shipped WITHOUT the termination power jumpers connected. Unless you have a larger SCSI setup, there is no need to connect the jumpers. According to the photo, you have all three termination resistor blocks correctly installed. My EIIIX is configured the same way, and boots...