1 Apr
2006
1 Apr
'06
3:49 p.m.
A few weeks ago I rescued a 6Mhz IBM AT in an unusual rack mount case
with a Plexiglass cover. I don't know how it got in that condition or
how anybody permitted it, being as it was not shielded. But I digress
.. (It is marvellous .. like the original case mod!)
It had a 5154 with it that displayed output, but the output looked as
though it was 'smearing' to the right. This made text look goofy. The
problem was more apparent in graphics modes. A different 5154 or worked
on the machine so it is definitely the monitor, not the EGA card.
I'm a monitor novice. I know these things pack a punch, so I have a
healthy respect for them. Are there any simple checks to make?
(I have the Sams guides for the 5151 and the 5153, but not the 5154 so
I'm kind of in the dark.)
The machine also came with a 5151 that doesn't work at all. I don't
even think it is getting power. For that one I can refer to the Sams guide.
As for the rest of the machine, it was fine except for the full height
hard disk. The hard disk would start spinning, but it sounded as though
it was making metal shavings - I don't think there is any hope for it,
so I replaced it with an modern IDE drive and controller. The machine
has 1152KB, EGA with daughterboard, monochrome card, IBM 5250 emulation
card, IBM token ring card, original BIOS and a single 1.2MB floppy drive.
2 Apr
2 Apr
12:24 p.m.
A few weeks ago I rescued a 6Mhz IBM AT in an unusual rack mount case
with a Plexiglass cover. I don't know how it got in that condition or
how anybody permitted it, being as it was not shielded. But I digress
.. (It is marvellous .. like the original case mod!)
It had a 5154 with it that displayed output, but the output looked as
though it was 'smearing' to the right. This made text look goofy. The
problem was more apparent in graphics modes. A different 5154 or worked
on the machine so it is definitely the monitor, not the EGA card.
First thing to lookl at : display text (or some graphics with vertical
lines) in each of the 3 primary colours (R, G, B). Is the smearing as bad
on each colour, or is one particularly bad, or what?
Most of the time smearing comes from one of 2 sources. Either dreid up
capactiors in the video circuits, or a low emission CRT. You'd better
hope it's not the latter.
I'm a monitor novice. I know these things pack a
punch, so I have a
healthy respect for them. Are there any simple checks to make?
There are high voltages in there, sure. On most of the PCBs, actually,
but at least the PSU is in its own box inside, so it's hard to touch
rectified mains (which is probably the most dangerous supply in the monitor).
I do have a schematic if yuo want me to go through it.
(I have the Sams guides for the 5151 and the 5153, but
not the 5154 so
I'm kind of in the dark.)
The machine also came with a 5151 that doesn't work at all. I don't
even think it is getting power. For that one I can refer to the Sams guide.
The 5151 is nice and simple. In fact the most difficult bit of repairing
one is getting the case off. There are screws under the little blanking
plates on top, screws on the bottom going in from the back side, and then
2 more screws on the bottom. To get the cover off, remove the blanking
plates, put the monitor face down, take out the screws under said
blanking plates, the 2 on the bottom going in from the back (now going
vertically downareds) and the 4 screws of the remaining 6 that are on the
rear part of the case. Do not remove the other 2 or the mains transformer
will fall onto the CRT. Seriously!
There is an internal fuse that might bave blown, if so, suspect problems
in the PSU or line output stages.
-tony
6839
days inactive
6840
days old
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