That looks just like my Presario 2286, but it has a different motherboard (part number 337362-001 for the 2262 and 387610-001 for the 2286). The two motherboards look identical, so I don't know what the difference is between them.

If it's the power supply shown in the Super User link (which is what the Presario 2286 uses), then pin 2 is 5VSB and pin 9 is PS_ON. Other than those two pins, it matches the AT connector pinout. There is no -5V, and the third connector is 3.3V and ground.

I don't know if 256MB modules will work in this motherboard. I had this same problem with a dead CPU, so maybe it's worth seeing if the heatsink is reasonably warm (not burning hot like the dead CPU I had, but also not room temperature), and you can check the voltage at the wire links marked R212 and R213 (next to the group of four caps between the socket and power connectors).

(Edited because I found motherboard part numbers)

I forgot one more thing. If there are no internal speakers, it will play POST codes from the unpowered speaker jack on the back (labeled red for some reason). Note that the 387610-001 motherboard has a design flaw that causes extremely low audio from this jack, but I'm not sure about the 337362-001.

Thanks for the information @lti, much appreciated. One correction, this computer is a 2266 and not a 2262, my mistake. But I couldn't find any parts differences between those two models.
Some more replies below:

If it's the power supply shown in the Super User link (which is what the Presario 2286 uses), then pin 2 is 5VSB and pin 9 is PS_ON. Other than those two pins, it matches the AT connector pinout. There is no -5V, and the third connector is 3.3V and ground.

That makes a lot of sense now. I measured the voltages at the pins of the P1, P2 and P9 power connectors and I'm a bit concerned about some of the values I'm seeing.
I'm listing the expected and measured values here for the next person who has to deal with this power supply.

My question is, is 4.71V okay for Pin1, or is it too low and should be closer to 5V? Same for Pin9, should it be closer to 0V?

(P1 and P2)
pin color voltage
------------------
Pin1 Orange +5V (4.71V)
Pin2 Purple +5V
Pin3 Yellow +12V
Pin4 Blue -12V
Pin5 Black 0V
Pin6 Black 0V
Pin7 Black 0V
Pin8 Black 0V
Pin9 Grey PS_ON (0.25V)
Pin10 Red +5V
Pin11 Red +5V
Pin12 Red +5V

(P9)
pin color voltage
------------------
Pin1 Black 0V
Pin2 Black 0V
Pin3 Black 0V
Pin4 Green +3.3V
Pin5 Green +3.3V
Pin6 Green +3.3V

I had this same problem with a dead CPU, so maybe it's worth seeing if the heatsink is reasonably warm (not burning hot like the dead CPU I had, but also not room temperature),

Good idea. I touched the CPU heatsink and it's certainly hotter than room temp, but not burning hot. Also checked the chipset heatsink and found it to be reasonably hot as well. I couldn't find any other burning hot chips on the board.

and you can check the voltage at the wire links marked R212 and R213 (next to the group of four caps between the socket and power connectors).

Did you mean the circled loops in the attachment below? What are these components? I'm not familiar with them. If I'm not misremembering, I believe I measured 2.9V on each of them. Is that too low as well?

I forgot one more thing. If there are no internal speakers, it will play POST codes from the unpowered speaker jack on the back (labeled red for some reason). Note that the 387610-001 motherboard has a design flaw that causes extremely low audio from this jack, but I'm not sure about the 337362-001.

Interesting!
Alas, I plugged in a pair of speakers to the speaker jack with the volume turned all the way up, but didn't hear any beeps 🙁
I'll see if I can hook up a PC speaker to the motherboard header, but I'm not too hopeful I'll get beeps. Could this behavior also point to a BIOS issue?

Also if anyone else reading this has a working 2266, I'd be really grateful if you could dump the BIOS for your machine and link it here!

Thanks

mkaushik wrote on 2022-08-31, 00:10:

My question is, is 4.71V okay for Pin1, or is it too low and should be closer to 5V? Same for Pin9, should it be closer to 0V?

Mine measures 5.08V, but 4.71V should be high enough for Power Good.

mkaushik wrote on 2022-08-31, 00:10:

Did you mean the circled loops in the attachment below? What are these components? I'm not familiar with them. If I'm not misremembering, I believe I measured 2.9V on each of them. Is that too low as well?

Yes, that's what I meant. Those are current shunts. In this case, they're on the CPU core supply, so 2.9V is correct for your CPU and jumper settings.

mkaushik wrote on 2022-08-31, 00:10:

Alas, I plugged in a pair of speakers to the speaker jack with the volume turned all the way up, but didn't hear any beeps 🙁
I'll see if I can hook up a PC speaker to the motherboard header, but I'm not too hopeful I'll get beeps. Could this behavior also point to a BIOS issue?

It could be the BIOS. The motherboard headers (J25 and J26) connect to the same amplifier, so you would have the same result. The PC speaker is mixed with regular audio, but only through the audio amp (not the line out or front headphone jack).

Have you tried stripping the computer down to the bare minimum required to POST? That would mean unplugging the IDE and floppy cables and removing the riser along with any expansion cards. The lack of beeps makes me think that you aren't likely to see any change this way, but it's pretty easy to try.

Have you tried stripping the computer down to the bare minimum required to POST? That would mean unplugging the IDE and floppy cables and removing the riser along with any expansion cards. The lack of beeps makes me think that you aren't likely to see any change this way, but it's pretty easy to try.

Yes I've tried unplugging the IDE connectors and removing the riser. No change in symptoms and no beeps.
I even tried unplugging the memory DIMM to create an obvious error, but no beeps were produced.

Anything else I could try?
Do you have any schematics / service manuals for this or related motherboards that would define test points to try and measure voltages? I'm attaching the ones I've found, but none seem to have this kind of info.

Thanks

I had a similar Compaq Presario socket 7 PC. Mine had a strange issue with the caps where it would power on but not post until it had sat running for awhile.
After that a warm boot would get a post. I am pretty sure that the board had bad caps, as it later completely died. But it worked for few years in that state.

Have you checked the motherboard for correct voltages and multiplier settings for the Cyrix CPU?
Most of those boards had options to run other chips and could be configured with different FSB and multiplier settings to accommodate accordingly. .
Also dumb question but have you checked the CPU to see if it is getting warm while running? Not hot but just warm? Re-socketed the cpu?

Solved! I had a bit of dumb luck with this one. Turns out it was faulty RAM preventing the machine from POSTing.
(I couldn't find a way to edit the title of the post or mark it solved)

Details:
As mentioned in my first post, I had tried a stick of 256MB PC-100 RAM earlier but the machine didn't boot with it.
According to the manual (see the attached screenshot) it only supports a max of 256MB of RAM:

What's weird is it mentions using a max DIMM size of 64MB, which would imply a max of 128MB for the machine since it only has two slots...unless I'm misreading it and the manual is implying 64MB per side of the DIMM.
Anyway, I dug through some of the old PC's I had lying around ("junk" according to the wife) and found a 128MB PC-100 stick in one of them. Despite the manual text about 64MB max, I decided to try it anyway and it now POSTs!

Thanks for everyone who responded above for their help. My next course of action would have been to recap the motherboard 😀

Attaching a few pictures of POST screens (the floppy drive was disconnected, hence the error)
Still quite a bit of stuff needs to be fixed.

• It has no HDD. I'll need to source an IDE HDD for the authentic spinning disk audio experience.
• The CDROM makes weird revving sounds and does not blink the status lights. I'll need to open it up, check for bad caps and oil the motors. I've always liked how the front bezel folds down when the tray ejects on this model, so I want to fix this drive.

I couldn't find a QuickRestore CD image for the 2266. The one for "2200 series" from Internet Archive installs Win95, whereas this machine came with Win98.
@lti can you please share the serial number from you 2286? That way maybe I can use the QuickRestore CD for the 2286 from Internet Archive.
Thanks

Mine works with 128MB modules, including an oddball one with only four chips (and it detected the full 128MB). I did once have the full 256MB in it, but since the chipset only caches 128MB, performance drops by a huge amount until you actually exceed 128MB used.

I don't remember if the CD requires a serial number, but it can at least tell if it's running on a Compaq and give an error if it isn't. If it does need a serial number, it's 3D91CGVBCON5. The only uncertain thing I can see is the audio. If this earlier motherboard has an ES1869, the 2286 restore CD should work. I would guess that the 2200 CD is for the older Cyrix MediaGX system.

The optical drive caps don't usually show visible failure signs, but the big ones (three 220uF and one 100uF) tested bad in mine. Unfortunately, it didn't last very long after replacing caps.

Thanks @lti.
Final update here, the QuickRestore CD for 2286 worked just fine for restoring Win98 onto the 2266. The audio driver worked as well. I did have to enter a registration key for Win98 First Edition OEM version.

That's good. I forgot that it asks for a product key, and either the previous owner of my computer lost it or Compaq didn't provide it.

Also, I'm now remembering that I had to restart one more time after Windows installation appeared to be complete, and then it went through the restore process a second time (starting at the GUI-based phase after it copied files from the CD and restarted the first time, then going through the full OOBE and asking for the product key). Anything I did before that extra restart (when it appeared that installation was complete) was lost. I remember some other Compaq restore CDs being broken in other ways.

I still don't know what the difference is between the two motherboards.

Tardy to the party, but nice to see people still enjoying older Compaqs. I have a 2286 I just got running right and was looking for chipset drivers for Win 98 (Looks like a SIS chipset, with the Cyrix M2-300 CPU). Mine didn't post initially as well, turned out to be a bad ram stick. It also randomly does not respond to keyboard presses during POST, but it doesn't hang. Eventually it starts responding. Also found out the max drive size that will auto populate is 65535Mb, which is higher than I thought it would go. I also learned that POST takes significantly more time with larger size drives (Had tried a 40Gb initially, went down to a 10Gb and drive detection finished more quickly).

Still looking for chipset, audio (I think I saw an ESS 1371 but have to double check) and bios. I think I'd like to have the latest, but not sure if I will risk it or leave it be.

I also disassembled, and cleaned the inside of the case, rubbed the motherboard and riser down with alcohol (no idea what was on everything, but it was nasty), de-stained the plastic front panel as best I could, and spray painted the case cover to put something over bare metal scratches. Looks a little weird with the color difference between the case cover and the front plastic, but not enough to do it again 😀

I'll post pics if interested, but I know it's an old thread. Oh one last thing, a single 256 Mb stick worked for me as well. I don't believe they had "dual channel" back in the days of PII/K6-2/M2 so I'm not sweating the lack of a matched pair.

Thanks for reading!

The chipset is an SiS 5598. I updated the graphics driver, but I just used the rest of the chipset drivers that were in the factory restore image.
https://www.vogonsdrivers.com/getfile.php?fil … &menustate=21,1

Audio is an ES1869 (not an ES1371, fortunately - ESS chips were good for DOS compatibility, but good luck getting an AudioPCI working). Strangely, the SiS 6801 Super I/O comes up as an AC'97 codec in those scam/malware "driver finder" websites, but it has nothing to do with audio. Once again, I'm just using the factory Compaq drivers in Windows, and I don't remember where I got the DOS drivers I'm using.

I don't think Compaq ever released a BIOS update.

I tried a 60GB drive once, but I don't remember it slowing down POST. I do remember it freezing on the Compaq splash screen with a defective CD-ROM drive once.

There was no dual channel back then, but the chipset can only cache 128MB. This chipset does support some weird high-density modules, so it seems pretty compatible. I'm running a weird 4-chip 128MB module in mine.

lti wrote on 2023-05-23, 19:34:

The chipset is an SiS 5598. I updated the graphics driver, but I just used the rest of the chipset drivers that were in the fact […]
Show full quote

The chipset is an SiS 5598. I updated the graphics driver, but I just used the rest of the chipset drivers that were in the factory restore image.
https://www.vogonsdrivers.com/getfile.php?fil … &menustate=21,1

Audio is an ES1869 (not an ES1371, fortunately - ESS chips were good for DOS compatibility, but good luck getting an AudioPCI working). Strangely, the SiS 6801 Super I/O comes up as an AC'97 codec in those scam/malware "driver finder" websites, but it has nothing to do with audio. Once again, I'm just using the factory Compaq drivers in Windows, and I don't remember where I got the DOS drivers I'm using.

I don't think Compaq ever released a BIOS update.

I tried a 60GB drive once, but I don't remember it slowing down POST. I do remember it freezing on the Compaq splash screen with a defective CD-ROM drive once.

There was no dual channel back then, but the chipset can only cache 128MB. This chipset does support some weird high-density modules, so it seems pretty compatible. I'm running a weird 4-chip 128MB module in mine.

I remember ES1869 being really compatible in DOS also, I have another machine I bought a Compaq ES1868F for and the old Sierra On-Line game music is spot on with what I remember as a kid. This machine does hang in weird scenarios though, and unless it's my keyboard, a lot of times I noticed it won't acknowledge key presses until a certain point in the POST (which step I have no idea, as there isn't any output besides the RAM count if I remember correctly)
I had a 120gb WD drive I threw in out of curiosity, and remember thinking it hung before I saw the disk light flash briefly during the detection. This model also doesn't seem to mind budget friendly IDE to SATA adapters. I have a Sinloon model plugged into the back of a DVD-RW and there is no delay or functionality compromise. It even boots off of CDs which I thought was really cool.

Don't know why they didn't add a fan to the M2 heatsink. I don't think the "pull" effect of the PS fan would be enough. I turned it on without the heatsink when I first got it to verify that it POSTed, and burned my finger on top of the chip. I'm contemplating an IDE to CF adapter, as it seems slow with disk activity and don't know if it's the machine or the ancient Quantum 10Gb I've got in it. Finally, I just remembered my machine had a bad ram stick also, which is what made me try the 256Mb stick. I wonder if RAM failures were common on this model?

Mine only displays the Compaq logo on POST until pressing Esc unless there is an error after initializing video (like resource conflicts). I have seen some hangs in Windows as well, and it seems like swapping RAM can affect stability a little. I never made it totally stable, but it's doing well considering the amount of stability problems I saw with Compaqs compared to other computer brands.

I feel like the IDE to SATA bridges will be more compatible with older ATA33/UDMA2 controllers like this one, but the older VIA chipsets still don't seem to work properly with DMA enabled. The big problem for me is the lack of analog CD audio, so an optical drive would just be there in case I need to boot from a CD (like when the 8GB Seagate U8 drive I installed finally fails - it has some bad sectors, but the original 4.3GB drive was a little too small for me).

It seems to work fine without a CPU fan. It's a big heatsink with wide fin spacing, but I do remember seeing a model that used the same motherboard with a K6-2/400 and the usual socket 7 heatsink/fan. However, I've put a 500MHz K6-2 in it with the original heatsink, and it doesn't get abnormally hot (50°C on a thermistor taped under the CPU). The Cyrix could run hotter, considering that my Presario 2286 was actually being thrown out because the CPU died. It was also unstable from the factory, and the original owner just thought that was normal with computers in general. I ended up finding a motherboard that included the CPU at a price I could handle (I don't like spending money on old computers), so I never figured out if the CPU was the problem the whole time or if the motherboard was the cause of the stability problems. The original CPU definitely wouldn't POST in the replacement board, and the heatsink got extremely hot in just a few seconds. With both the good MII and the K6-2, the heatsink warms up slowly and settles at just being warm. The original RAM module was still good, but 32MB is low for Windows 98 (this was one of the cheapest computers available when it was new).

lti wrote on 2023-06-03, 21:00:

Mine only displays the Compaq logo on POST until pressing Esc unless there is an error after initializing video (like resource conflicts). I have seen some hangs in Windows as well, and it seems like swapping RAM can affect stability a little. I never made it totally stable, but it's doing well considering the amount of stability problems I saw with Compaqs compared to other computer brands.

I feel like the IDE to SATA bridges will be more compatible with older ATA33/UDMA2 controllers like this one, but the older VIA chipsets still don't seem to work properly with DMA enabled. The big problem for me is the lack of analog CD audio, so an optical drive would just be there in case I need to boot from a CD (like when the 8GB Seagate U8 drive I installed finally fails - it has some bad sectors, but the original 4.3GB drive was a little too small for me).

It seems to work fine without a CPU fan. It's a big heatsink with wide fin spacing, but I do remember seeing a model that used the same motherboard with a K6-2/400 and the usual socket 7 heatsink/fan. However, I've put a 500MHz K6-2 in it with the original heatsink, and it doesn't get abnormally hot (50°C on a thermistor taped under the CPU). The Cyrix could run hotter, considering that my Presario 2286 was actually being thrown out because the CPU died. It was also unstable from the factory, and the original owner just thought that was normal with computers in general. I ended up finding a motherboard that included the CPU at a price I could handle (I don't like spending money on old computers), so I never figured out if the CPU was the problem the whole time or if the motherboard was the cause of the stability problems. The original CPU definitely wouldn't POST in the replacement board, and the heatsink got extremely hot in just a few seconds. With both the good MII and the K6-2, the heatsink warms up slowly and settles at just being warm. The original RAM module was still good, but 32MB is low for Windows 98 (this was one of the cheapest computers available when it was new).

Interesting! Mine only displays the Compaq logo until pressing ESC also, but sometimes ESC does not do anything. If you wait a few seconds and try again, sometimes it responds, sometimes it doesn't.
I agree with you on the analog CD audio. I would have preferred to have that also, but the money topic comes into the picture. I've tallied up what I've spent on my "vintage hardware jaunt" and realized it was way more than I ever intended on spending. I happened to have the SATA drive from a hardware pull, so I saved the 30+ dollars you'd expect to pay finding a new old stock EIDE unit.

I personally think 2266 and similar would have benefit from a CPU fan. The venting scheme is also questionable, as the intake on the left side, if I'm not mistaken, is lined up with the backside of the riser card. The airflow would have to travel around the riser before getting to the main area to be exhausted by the PSU fan. The PSU doesn't benefit either, as it's being cooled by "pre-warmed" air in this case, which does it no favors long term. Granted, these are probably small numbers compared to today's hardware, but over time, I wonder if a CPU fan and better venting would have made it more stable?

I have a 16Gb CF card and IDE to CF adapter left over, I was thinking of trying out to see how much of a performance difference there is. The Quantum 10Gb I have is okay, but I have a feeling it's slow. Thanks for sharing, this has been interesting!

Yeah, and there's a gap between the power supply and the vent on the right side of the case. The power supply fan gets pretty loud (by my standards), and I don't feel much air coming out of the case vents. Nothing seems to get hot enough to affect stability, but I definitely wouldn't swap the fan for a silent one. If you want to add a CPU fan, there's enough room for standard socket A heatsinks, so you can use one of those with a power adapter (the motherboard doesn't have any fan headers).

For the hard drive, disk benchmarks will tell you if it's performing as expected. Make sure DMA is enabled in Device Manager. From what I remember, it should be enabled by default for hard drives and disabled by default for optical drives (I guess there were some DMA-related problems with optical drives back then - I haven't had a problem with it, so turn it on while you're in there).

Amazing to see other 2266 users!

I’ve got two myself due to childhood nostalgia for this particular model. One I’ve upgraded to a Pentium MMX with fan/256MB RAM/16GB CF storage/Voodoo 3 2000 gfx/48x CD-RW/ethernet. The other I’ve kept mostly stock aside from CF storage (kept at 4GB for authenticity) and RAM upgrade.

I love using it for era-appropriate gaming, browsing the web with The Old Net proxy (set to 1999), AOL IM (via AIM Phoenix server) and BBS communities.

Knowing that the 2286 QuickRestore will work tells me what I’ll be doing tonight, so thanks!

SnazzyGent wrote on 2023-06-06, 00:47:

Amazing to see other 2266 users! […]
Show full quote

Amazing to see other 2266 users!

I’ve got two myself due to childhood nostalgia for this particular model. One I’ve upgraded to a Pentium MMX with fan/256MB RAM/16GB CF storage/Voodoo 3 2000 gfx/48x CD-RW/ethernet. The other I’ve kept mostly stock aside from CF storage (kept at 4GB for authenticity) and RAM upgrade.

I love using it for era-appropriate gaming, browsing the web with The Old Net proxy (set to 1999), AOL IM (via AIM Phoenix server) and BBS communities.

Knowing that the 2286 QuickRestore will work tells me what I’ll be doing tonight, so thanks!

Nice machine! Was your 2266 equipped with the Cyrix M2 originally? I know CPUs are socket compatible, but have no idea on cross manufacturer support. I managed to find a quick restore CD, but it's in Spanish. Couldn't successfully change the language as Windows apparently wasn't set up to be able to switch regions back then. There are SOME region settings, but a lot of the strings seem to be hard coded based on the region that the Quick Restore was made for. Otherwise, it worked pretty well, drivers were installed, no issues on Device Manager.

vintageGuy81 wrote on 2023-06-06, 13:10:

SnazzyGent wrote on 2023-06-06, 00:47:

Amazing to see other 2266 users! […]
Show full quote

Amazing to see other 2266 users!

I’ve got two myself due to childhood nostalgia for this particular model. One I’ve upgraded to a Pentium MMX with fan/256MB RAM/16GB CF storage/Voodoo 3 2000 gfx/48x CD-RW/ethernet. The other I’ve kept mostly stock aside from CF storage (kept at 4GB for authenticity) and RAM upgrade.

I love using it for era-appropriate gaming, browsing the web with The Old Net proxy (set to 1999), AOL IM (via AIM Phoenix server) and BBS communities.

Knowing that the 2286 QuickRestore will work tells me what I’ll be doing tonight, so thanks!

Nice machine! Was your 2266 equipped with the Cyrix M2 originally? I know CPUs are socket compatible, but have no idea on cross manufacturer support. I managed to find a quick restore CD, but it's in Spanish. Couldn't successfully change the language as Windows apparently wasn't set up to be able to switch regions back then. There are SOME region settings, but a lot of the strings seem to be hard coded based on the region that the Quick Restore was made for. Otherwise, it worked pretty well, drivers were installed, no issues on Device Manager.

Thanks!

Yes, it originally had a Cyrix MII which is a great chip and in some cases outperforms the Pentium MMX. I learned a lot about CPU jumpers doing the swap!