Question : Problem: monitor goes black

Usually, everything works fine.  Occasionally  (twice this week already) my monitor goes black.  The computer is still running fine, I just can't see anything.  I replaced the monitor hoping to solve the problem, but no luck.

When this happens, I disconnect from power, then reboot.  At re-boot, I make it past the memory test OK, but before it can finish booting up, before testing extended memory, all goes black.  Boot up continues, I just can't see it.

After several re-tries, it will finally boot up complete with display.

Today all ran well for 16 hours, then, while doing a backup -- black screen appeared.  Earlier this week it happened when I touched the spacebar to terminate the screen saver (Razzle Dazzle).

This is a 486 dos set up, about 6 years old, used as a cash register.  

I had a pretty old RGB monitor; replaced it with a new thin flat screen Samsung.

Any ideas?  If you're getting ready to tell me to buy a new computer, I worry that my DOS cash register program won't work under windows.  It's a perfectly excellent program that I don't want to give up.  Windows seems so touchy; DOS has been rock solid for our store situation.

Whitley



Thank You all for your ideas, I'll just have to wait for the problem to happen again to try your remedies.

One more symptom I just remembered:  One day, twice in a row, as it was booting up, it reported that the memory test failed.  At the third try to boot up, all went well and has been OK for a week.  Was that just a quirk or maybe related to my blackout problem?

Answer : Problem: monitor goes black

First, it may be a video card, cable or a motherboard. If it's a motherboard or a video card you can no longer get as a direct replacement, you'd be better off to go to another computer. Unlike what you said, this is very appropriate and easily possible.

There is no reason why you cannot use a replacement computer, but continue to use DOS. You'd need to simply verify that the I/O devices the old computer used can connect - this class of computer used ISA almost exclusively for add-on cards.

here's how:

Verify the type of I/O card used in the computer, if any. If you can't get a similar card for this part, you might have a problem.

Verify the level of DOS you are using, and either use your  old install disks or buy new ones at the level you were at (DOS 6.3 or whatever).

Utilize a parallel-port -based backup tape unit to copy all your data off your hard drive as an image,, rather than trying to reuse the old drive. This allows you to set up a newer machine and test it before you transition.

Acquire a newer computer (almost anything would be an improvement) - I'd recommend a good pentium or K6 motherboard with PCI as well as ISA (if your previous boards need it). All video cards work the same way with standard VGA modes, so everything will display the same way. Install the interface boards (if any) for the cash drawer(?)

Use the DOS startup disks and perform a FDISK and then a FORMAT of the C: drive on the NEW computer. Load the  DOS, restart then load the backup/recover software. Recover the backup to the new drive. Restart, and it should work the same way, but faster.

I'd love to hear how this all works out.

David