Here's a wierd one.  I have a 486DX/66 with VGA and 8MB RAM.  I installed a
CDROM, soundcard and cleaned it up significantly since I got it (used).

Every once and a while it comes up as if it were a B/W monitor...no color.
I power off/on the monitor to no avail.  I warm boot to no avail.  But a cold
boot usually (or always) brings back the color.  (cold boot = full pwr off,
yes?  warm boot = CNTRL/ALT/DEL, yes?)

Is this a bad video card, a screwy monitor, a loose connection or dirt/dust
in a connection (the thing was _filthy_ with sticky dust when I got it.  I
had to clean it up with dry brushes, windex and spent two cans of compressed
air).

Only other problem(s) I have is two particular audio CD's sound scratchy, even
after running a CD cleaning disk several times, but most CD's play fine.  And,
the power supply (I think) groans every once and a while which either goes
away by itself, or if I smack it upside the head, or, might have to do a cold
boot.

What do you think?

24 responses total.

Groanning power supply = fan going on the fritz.  (Or the CPU fan.)

Yep, I took my CPU fan out because of the groan. (It'sa 486DX33 didn't come
with a fan)  I left the heatsink, though, and build and installed a heat sink
for my S3 chip on the video board.  For a while jiggling the case made the
groan go away, but I didn't like to think what that could do to a HD.

As to the video stuff.  I would say loose or dirty connection.  Depending on
where you used the windex, could a little residue from that be acting toward
this behavior?  Pull the video card and carefully erase the card edge.  With
a pencil eraser to clean it.  Put it back in.  Make sure your cables are clean
and tight, too.  Good luck and have fun and For God's sake Ground Yourself!
;)

Purchase Radio has some cans of spray cleaner for this sort of greasy 
dust.  I had (have) an Apple SE/30 which had video static problems
which , I believe, were caused by much deposited cigarette tar. This was
resolved by  taking the thing apart and putting it back together 3 times.
After that  and trying to get it to stabilize each time, I ran it for 
about 10 hours in my shop. When I returned the room smelled like someone
was in there smoking a cigar. ie, dirt and grime can be a problem.
The machine is still running strong.

Thanks all.  Yes, the greasy dust seems to be from tobacco, smells like it!
I've gotten _clouds_ of dust out of every part several times.

I think the groaning fan is in the power supply, which seems to be retaining
the most dust (getting better with each cleaning though).

re the color problem...it had gotten worse.  I started up a color program and
then it went to monochrome.  I checked the system using MSD and it told me
I had a VGA monochrome display!  So, I played with the connections (I had
installed a monitor extension cable) and got my color back.  Silly old me.

I will be opening up this box for another cleaning several more times, but
for now, I'd limke to just try and enjoy it!  Oh yeah, I AM careful to ground
myself and discharge any static before i touch anything...thanks for the
reminder   ;)

<Chaz smiles>

The best way to clean PC power supplise is to yank them out, take the 
screws out that hold them together and blow the dust out with compressed
air.  Lacking that, remove the fan and *wash* the electronics with soap,
water and a brush.  Yes, I have done this *many* times.  I also do it to
mother boards and cards.  Just remove things that are not water proof,
like speakers, or where water is difficult to get out of, like fans.  If
you have compressed air, use that to blow off access water and then let it
sit in a marm spot to dry off for 24 hrs.  If you don't have comp. air, 
sling access water off as best you can.  BTW, I always use HOT water!  His
is the best way to remove tobaco stink and the like.
 
Aprehensive about doing this?  Keep in mind that the PC boards in your PC
were wave soldered at 500 to 600 F.  Hot water can only be heated to 212 F.
After wave soldering, the boards go into a fancy dish washer to clean off
the flux, etc.  Yea, go ahead and stick all those PC boards in your dish
washer.
 
Just be sure everything is good and dry before powering things up  ;)

Well...now I REALLY feel dumb!  The connection(s) I tightened were for the
extension to the serial mouse, not the monitor!  I'm still having the
monochrome problem intermittently.  What is _really_ odd is that color screens
for MSD or Telix will be monochrome, but when I startup Windows (3.1) I get
the Microsoft Windows title screen in color, but the program loads up and I
get only monochrome (ie; B/W -> color -> B/W all in the same session).

Anyway, the way I have the desk and room set-up I'm not going to pull
everything apart for the immediate future to open the box again for another
cleaning.  As it is, I have to nearly stand on my head to see over the
mini-tower and get to the connections in the rear (that's probably how I
mistook the serial mouse cord for the monitor cable...didn't look close
enough).    8*(

  This is of no help, but I thought I'd mention that I had the same VGA
problem a few years back.  Once in a rare while, the computer would boot
up convinced that I had a mono VGA card or monitor.  It's a mystery I
never solved; I have a different monitor and card now.

Could it be something non-digital like the resistors and capacitors that keep
the bus signal clean?  If one of those started to 'go' would that leace odd
timing and waveform residue on the bus confusing the processor?  Such a
problem would be dependent on temperature, magnetic field, current bleed
resulting from humidity or other trace conductors.  It might appear completely
random, and it might manifest differently depending on starting and ending
mode and suchmuch.  The possibilities are endless.  If the bus was just noisy
enough...

I would suspect something isn't making good contact.  Are all the pins
in the mini BD-15 vidio plug making good contact?  It is very possible
that the contacts in the female (PC end) have been loosened to the point
where the pins no longer make good contact.  If possible, verify that
none of the wires inside the cable between the monitor and PC are inter-
mitent.  Since these places are out in the open, they can see a lot of
abuse and stress.  Of course it may be something electronic too.  Heat
cycling does stress electronics.
 
See if it's a problem with the CPU or the monitor.  Connect the monitor
to a known good CPU, then connect your CPU to a known good monitor.  That
should narrow things down a bit.

If you suspect a problem with a connection, it wouldn't hurt to just reseat
the cards and see what happens.

Yep to #10.  That switching to known good always helps lots, and I always
forget about it until someone says something. 

Well, I've re-tightened the screws that hold the monitor cable in place, still
haven't re-opened the box to double check the connections in there.  The
problem still exists, but is less frequent now.

I went to Computer Medic and found a copy of the motherboard manual for this
machine...in the process, comeone told me they had heard of a similar problem
which was caused by a failing battery.  Seems it would not resolve with a warm
boot because of the battery, but a cold boot could cause something in the
set-up (bios, cmos stuff I'm only vaguely knowledgeable about) to re-set and
I get the color back.

did I mention that MSD shows I have a monochrome VGA when the color goes out?

This is great learning stuff for me...thanks for keeping up the comments. 
I do plan to upgrade this system to SVGA and will therefore get a new video
card and monitor...but I have to wait a while for the $$$  ;-)

During a cold boot the VGA card or its BIOS looks at the connection to the
monitor and decides if the monitor is color or monochrome.  The wiring 
inside the monitor is different between color and mono.  If you cold boot
a system without the monitor attached it will assume that you have a
mono monitor, even after you plug it in.

Undoubtedly, you have a loose connection somewhere, possibly inside the
monitor itself.  Some monitors have cables which plug into the back of
the monitor rather than being soldered inside.  If your monitor is
built this way, have you checked that that connection is tight?

Yes, the monitor cable is attached to the monitor (not a removable
connection), but the b/w thing has gotten so frustrating lately I decided to
swap the monitor for an SVGA one I knew to be good from another system.

[to digress, I still can't figure out why I only get monochrome, _except_ for
the opening screen for Windows 3.1 which comes up in color, then the program
manager and other windows go back to monochrome.  To me, very strange.]

anyway, after I switched the monitors I got good color (only VGA, even though
it's an SVGA monitor, btw).  So, after a while I decided to put the "bad"
monitor on the other system I took the SVGA from.  Guess what?!?  It runs
color without going to monochrome!  I'm going to keep them switched for awhile
and see it one or the other reverts to monochrome.

The strangeness continues...

Oh yeah, on the other hand, if I want to be able to utilize my SVGA color to
fullest, is there a software solution or do I have to upgrade the card itself?
If I upgrade the card, should I consider more video RAM, and what should I
expect to look for by way of specs, price, etc?  I hate to go into a store
with little knowledge and be completely at the mercy of some salespern, even
a store like CCS where I think they are honorable and know what they are
doing...not all the salesperns are alike.

An SVGA monitor is a bit vague as to what its capabilities are (SVGA is a
fairly ambiguous term).  Generally the manuals for monitor and cards will
tell you what resolutions they can support, and what the maximum frequency
of the monitor is.  Your card *may* just need software to fully utilize the
monitor, or it may just need more RAM added, or it may need to be replaced
entirely.  It depends on what kind of card it is.  Do you have a manual?

Specs for purchasing: first, what type of bus do you need: ISA 8-bit,
ISA 16-bit, EISA, VLB or PCI.  Next, what resolution and "color depth" do
you want, like 800x600x256 colors, or 1024x768xmillions of colors, or ???.
The amount of memory on the card is a big factor in what determines those
stats, but you can just read the specs on the card for what resolutions
it supports.  The manual may give multiple listings, depending on how 
much RAM is installed on the card (i.e. with one meg, with two megs, etc.)
Next, pay attention to acceleration features...if you're a big Windows
user, you'll probably want a card with hardware Win acceleration.  You
kind of have to know the brands and chips, or trust someone else's
judgement on this.  Some cards advertise various benchmark scores, but
they can be somewhat distorted (e.g. by picking an older version of a
benchmark program that gives a higher rating than the current version).

Both the systems in question were bought used, without and documentation. 
I have acquired the motherboard manual for one of them, but no specs on the
monitors or video cards.  The SVGA monitor is labled such on the fron of the
case (ie; below the screen).  If I recall, it is a Magnavox.  I'll have to
dig a little deeper to find the model and specs (if they are available).

Thanks rob for the guide to buying.  I've been thinking about getting a 15"
or 17" high resolution monitor for awhile, and therefore I'd likely need to
upgrade the card with it.  You've given me some pointers to review my readings
from Upgrading and Repairing PC's.
                                                                        ;

A lot of the monitor and card manufacturers have web sites where you can find
documentation  and drivers.  The card should say who made it on it somewhere.

Or if not, a number of "system info" programs will scan the BIOS on the
card and look for strings like (c) and Copyright, displaying any matches,
which at least tells you who made it and in roughly what era.  Also, if
the VGA card's BIOS has built-in VESA support, then many VESA-compliant
programs will query and display the possible video modes quite reliably.
(VESA support is another good feature to look for, but I'd think almost
all new cards would have it nowadays (though I haven't actually checked)).

On DOS you could try "msd", which looks at various things.  

PC boards in the *dishwasher*?  Guess I can't argue with success, but are 
you *sure* the dish soap isn't corrosive?  On the other hand, I've heard 
of people doing this with tubes, so...

Dish soap does do funny things to the surface of unfinished aluminum...

You may want to run your PC boards separate from your dirty dishes to food
particles from lodging between the IC pins.  Perhaps with a little Tide
detergent.  I just flush the boards I'm cleaning with hot water, scrub with
a tooth brush and a bit of Tide to loosen the gooies, like tar, then rinse
with hot water again.

I once visited Ann Arbor Terminals here in town, when they were still in
business.  Indeed, they really and truely *did* use a dishwasher to wash
the flux off.  They didn't use any dishwater detergent, and mentioned
that the stuff was indeed very corrosive.  It was definitely an "under
the counter" dishwasher, and it may have been a perfectly ordinary
domestic dishwasher, kitchen-aid or the like.

The only difference between the "fancy" under the counter industrial
hobart dishwasher, and your ordinary domestic dishwasher, is that the
home unit has more cycles and an air blower to dry the dishes in the
washer.  In the industrial unit, a human takes the dishs out while
they're hot enough to burn, and the residual heat (plus a large fan)
dries the dishes in a matter of seconds to minutes.

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