Subject: Re: My 3/60 keyboard (and monitor)
To: None <>
From: Paul Boven <>
List: port-sun3
Date: 12/03/1995 23:58:06
Hi tsunami,
> works now.  I took the fuse out of the socket at the front of
> the motherboard (away from all the connectors..) and put it in the socket
> at the keyboard port (is this a bad thing to do?) and it works now.

uhh... I'd guess something else is without power now, and that's not good of
course. If it won't netboot, you found the ethernet-fuse :)

> But, now (this happened before too, but I was hoping it would go away), 
> the monitor kind of phases out, like an old tv.  I think it might be
> aliens.  Any better suggestions?  It seems to be the framebuffer rather
> than the monitor (turning the monitor off for a bit and then back on
> doesn't do anything, but turning the whole system off for a while then back
> on fixes it).  Hitting the monitor has soem effect (it causes it to
> display different patterns of stripes).

My 19" monochrome has the same problem. It is, in my situation, *only* a monitor
problem. What has happend is that in it's long and usefull life, the sync-circuits
in the monitor got a bit misaligned, probably by ageing. I have exactly the same
symptoms, but they go away as the monitor heats up. 
This hasn't been a problem so far, as starting X would take longer, but with 
the new SCSI-DMA (kudos, boys!) my Sun now boots faster than it's monitor does.

Remedy: First, DON'T hit the monitor. Hitting electronics is never a good idea, 
even though it sometimes seems to help short-term. Worst case, you'll break the
glowing filament in the cathode of the tube, and your monitor will go from mono-
chrome to zerochrome. The dreaded eternal screenblank. 
By the way, why are you hitting the monitor when you're so sure it's a 
framebuffer problem? :)

What you have to do, is to readjust the sync-circuitry in the monitor. It's best
to have someone with some experience in electronics (TVs) do this. As this exposes
some dangerous high voltages, don't try this on your own. Have at least someone
stand by to disconnect mains to the monitor, and *after* that help you.

(Yours truly once almost died when fixing someones colour TV, because only for 
a small moment he was caught off-guard, and zapped by part of the HV. I was
dazed for a few minutes, lying on the ground, alone. Had half a bottle of
Coca-Cola to get a back to life a bit, then I realized how close it had been,
and downed the other half. About 15 minutes after that, someone happened to show
up. I *never* do HV electronics alone anymore.)

When you open the monitor, and remove the shielding metal, you'll find a row of
labeled potentiometers that control the operating parameters of the syncs. You
can adjust height, width, offsets, and of course the frequency. It is the latter
that has to be adjusted. Only do adjustments when it's off, and even then with
a fully insulated screwdriver, because of possible remaining high-voltage in 
parts of the circuitry. 

Before reassembling, turn everything off for a long while, so it can get back
to room-temperature, and see how it behaves on power-up. I should have done that,
now I need to readjust it again.