View Full Version : PS/2 Model 30 286 seems to be dead

February 15th, 2016, 04:23 AM
So, I finally got a PSU for this thing, installed it with great enthusiasm went to power it up and... Nothing, nada, powers on, but no display. the NIC card lights up and the FDD sort of initializes but other than that it's completely dead, now, I've tried various things, different ram configurations, removed all of the expansion cards, disconnected the FDD,still nothing. The only thing I can conclude is either I have a rather good looking paper weight with a dead planar, or it's refusing to start because it doesn't have the Dallas clock battery installed. Could that be the problem? Not sure if it's worth investing more in this machine. Thank's.

February 15th, 2016, 06:35 AM
Shouldn't matter if the Dallas block is good or not. I don't think it should matter either if the PSU is even plugged into the planar either. Poke the voltage rails to see if +5 or +12 are coming up at all, if not you probably have issues within the riveted power supply.

February 15th, 2016, 06:52 AM
The voltages all seem fine.

February 15th, 2016, 07:07 AM
So I checked the voltage across a few electrolytics and this one here has no voltage across it. Any reason why it may have no voltage?


February 15th, 2016, 08:22 AM
But the other caps DO show a voltage in the ranges I said above?

February 15th, 2016, 08:39 AM
yep, 12 and 5 both rails seem pretty healthy too, haven't drifted much, and are stable. Starting to worry this is the planar.

February 15th, 2016, 08:47 AM
Oh, pardon me, I thought you said it DID NOT power on. My bad.
In that case, is the dallas module installed at all?

February 15th, 2016, 08:54 AM
Lol, no worries. Nope the module completely missing.

February 15th, 2016, 10:09 AM
I'd expect that cap to have voltage across it, just being a large electrolytic you'd expect it to be filtering a power line (but I could be wrong) so it might be worth tracing it's path and checking for continuity. If the motherboard was removed, I'd also check underneath, it's quite easy to scratch traces when removing on these if you're not careful.

This is just guesswork / easy things to check from my experience with Model 30 286's - not an expert opinion or anything like that.

February 15th, 2016, 10:57 AM
It's really not that big of a capacitor, 2.2uf 50v. Could the missing Dallas chip be my problem here?

February 15th, 2016, 11:18 AM
the socket needs to be populated. it won't boot if it's missing. it will boot if it's dead, but not if it's missing.

February 15th, 2016, 11:23 AM
Hmm seller on eBay has two listed for 8 each, suppose I'll grab one and give it a try.

February 15th, 2016, 11:55 AM
do you still have the old one?

February 15th, 2016, 12:07 PM
It never had one to begin with.

February 15th, 2016, 12:14 PM
aaah, once you put one in, it should boot normally. assuming there's not another component that's causing it to hang after you've got that installed.

February 17th, 2016, 03:59 AM
Welp, clock chip came today, still dead.