VOGONS

Search

Common searches

Fixing a Pentium MMX - 1 low beep, continous high beeps

Topic actions

First post, by JimKusznir

Posted on 
User metadata
Rank Newbie
Rank
Newbie

Hi:

I have a Pentium 1 MMX 233Mhz I've been asked to fix. It was working, turned off for ~6 months, then when it was turned back on, I'd get the normal successful single beep (normal pitch), then I'd get a continuous string of rapid higher pitched beeping. If I had to guess, I'd say the rate of the beeping is 50% on/off ratio, and more than 10 beeps per second. With different video cards, its a bit different. Some take longer before the continous beeping, some its instant. With no video card its about 1 second after the post successful beep. In all cases, the display never lights up, and the HDD light never blinks, suggesting no attempt to boot.

I pulled out all cards and unplugged all drives and accessories except CPU and RAM. I've tried 4 different video cards of three different varieties (one of which was the original trident card it came with). I suspected it was video in nature, but perhaps not....

I have reseated the CPU and RAM (and I have cleaned the edge of the RAM). I only have the one DIMM, no spares, so nothing to test with.

I don't know if my alternate video cards are compatible: Matrox Mystique, 2x ATI Rage XL. I know it was working with a Trident TGUI9440.

I'd like any pointers. While I did build systems of this vintage when it was "new", that was a long time ago 😀 I also don't have much in spare parts to experiment with. I haven't been able to find the beep code referenced in the mobo manual (Asus TX97). Am I just hosed (dead mobo or CPU?)

Thanks!
--Jim

Reply 1 of 10, by Caluser2000

Posted on 
User metadata
Rank l33t
Rank
l33t

Try replace the cmos battery. Dead flat batteries can cause some systems all sorts of strife.

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 3 of 10, by H3nrik V!

Posted on 
User metadata
Rank Oldbie
Rank
Oldbie

That kind of fast beeping, I have only heard when leaving stuff on my keyboard, pressing down the buttons 🤣 Might the keyboard be defective?

Also, how does the different capacitors look - bad caps could, like CMOS battery, cause all sorts of strange errors.

Please use the "quote" option if asking questions to what I write - it will really up the chances of me noticing 😀

Reply 4 of 10, by appiah4

Posted on 
User metadata
Rank l33t++
Rank
l33t++

More info about motherboard make/model and bios please. Photographs would be nice.

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 5 of 10, by chinny22

Posted on 
User metadata
Rank l33t++
Rank
l33t++

Quick google seems to suggest the Asus TX97 uses an Award Bios which is pretty typical of Asus.

So the key is to find the Award BIOS beep code list, something I'm struggling to find today. Most useful seems to be from Gigabyte (which is fine as Award wouldn't bother changing the codes between vendors)
https://www.gigabyte.com/Support/FAQ/816

From what you describe it could either be:
Memory Error Continuous long beep
Memory not correctly installed Continuous short beep

So I'd go with replacing the ram as well.

Reply 6 of 10, by JimKusznir

Posted on 
User metadata
Rank Newbie
Rank
Newbie

Thank you all.

First, there is no keyboard plugged in during these tests (I've stripped it down to mobo, cpu, psu, and ram). I only have a single stick of ram. I did notice a couple caps with a slight bulge on the top and one that looks like it may have leaked a bit right next to the CPU, so I'm guessing bad mobo. Looked on e-bay, and I can get a 32MB DIMM for $5 delivered, so I'll buy that and if that doesn't do it, a new mobo (looks like about $50) will be next purchase...

Upon very close inspection, one pin of the DIMM looks a bit off. I used the rubber erasor trick and shot some contact cleaner into the slot there, but still no go. So both the ram and the mobo have a hit against them as probable cause.

Thank you for your help!

Reply 8 of 10, by Horun

Posted on 
User metadata
Rank l33t++
Rank
l33t++
JimKusznir wrote:

I only have a single stick of ram. I did notice a couple caps with a slight bulge on the top and one that looks like it may have leaked a bit right next to the CPU, so I'm guessing bad mobo.

Did you try the the one ram stick in all the mem slots ? Any bulge in a cap is a bad sign and any that actually leaked is worse. I had a good board that was stored a year later it didn't boot and noticed 4 caps had bulged and all 8 were bad. You could either fix the bad caps or replace the board. Right now many Pentium boards are fairly reasonable if you look around.

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 9 of 10, by JimKusznir

Posted on 
User metadata
Rank Newbie
Rank
Newbie

A new stick of RAM AND a replacement video card were required, but the machine is now posting. Of course, the couple caps that have a small bulge don't give me high hopes for the longevity of the board, but its running now...

Thanks for the help!

Reply 10 of 10, by Windows9566

Posted on 
User metadata
Rank Member
Rank
Member

recap it, you just need capacitors, i recommend Rubycon, nichicon, panasonic, etc. and some soldering/desoldering is required.

R5 5600X, 32 GB RAM, RTX 3060 TI, Win11
P3 600, 256 MB RAM, nVidia Riva TNT2 M64, SB Vibra 16S, Win98
PMMX 200, 128 MB RAM, S3 Virge DX, Yamaha YMF719, Win95
486DX2 66, 32 MB RAM, Trident TGUI9440, ESS ES688F, DOS

Go to top of page Go to top of page
Back to General Old Hardware
Close window
Close window