Is it trying to use the same IRQ as the video card, IRQ 9? (Video Card may say '2' but it's really 9) Or possibly the IDE?
Try swabbing the end connector.

If that isn't the problem, try changing that BIOS optioning for hard disk RAM area from :300 to DOS 1K.

Moogle! wrote:

Is it trying to use the same IRQ as the video card, IRQ 9? (Video Card may say '2' but it's really 9) Or possibly the IDE?
Try swabbing the end connector.

If that isn't the problem, try changing that BIOS optioning for hard disk RAM area from :300 to DOS 1K.

Yeah, an IRQ conflict did occur to me as I was making this post; the unfortunate thing is that the 3Com card is the only add on card I have plugged into the thing -- everything else including video and IDE is onboard. That in itself wouldn't be too bad, except the BIOS configuration on the Compaq Deskpro/Prolinea is... shall we say... limited. I'll take a look tomorrow to see if I can change anything like IRQ or I/O address for onboard devices. I'm not holding my breath. I'm also reasonably certain it is not a PnP aware BIOS for it to assign the card some resources.

That all said, I know from (20 year old) experience that this card definitely works with this computer. I don't remember having to do anything special either... but that was 20 years ago.

So are you sure you use the right etherdisk for the ISA card version?
This disk works with my cards: ftp://retronn.de/driver/3com_LAN/3C509B_ISA/3c509b.exe
If the config utility does not detect the card then something more serious is not working. Like having corroded contacts that may require several attempts of replugging to the slot.

Onboard stuff does still use IRQs, though. Have you used a system info utility like CHeck It to see what IRQ, DMA, and other resources are in use?

Well, I tried lots of things, including the "PnP Disable" function of the EtherDisk utilities.. no go. Put the card in another slightly newer computer that has a PnP BIOS, and no go. Thought that maybe this card would be weird and require -5V, so found a power supply that provides -5V, and still no go. 3C5X9CFG insists there are no Etherlink III cards in the system.

I'm pretty pissed.. I think I have a dead card, despite it appearing to be in near pristine condition. What burns me though isn't how much I paid for it (a whole $16) so much as it is how long I waited for it to arrive (almost eight weeks).

Aw that would suck indeed. I wouldn't pay that much in an etherlink III card personally (I have many spares that I paid for a really low price)

I don't think these cards are requiring -5V even though I never tested one of them without -5V

One thing you may try is to install one of these in a computer running windows 98SE. I recall having many issues running one of my etherlink under DOS and windows 95, but under 98, since it installed everything needed, it was perfectly fine and I could configure it and thus checking that it was fine.

Try to disable everything you don't need in the bios and launch 3c5x9cfg under MS-DOS without anything started, maybe it uses an IRQ already in use and so it conflicts with something else that makes 3c5x9cfg unable to detect it

Yes, I think I will try installing Windows 98 on the Pentium computer (with PnP BIOS) that I'm trying to diagnose this thing in. I too have had experience with Windows 98 "just working" with hardware like this. I did remove all other peripherals when I tried this earlier, but just remembered I didn't disable the onboard audio.

I'm really hoping that this is just a fringe case of the previous owner disabling PnP and setting the I/O ports and IRQ on the card manually to something screwy.

There's a fellow on eBay selling new in box Linksys LNE2000T ISA ethernet cards that work fine. I have one in my jazzed up 486, and it works fine, but I've lost interest in horsing around with it for the time being.

So, tried it under Windows 98 and same story, no card detected. I guess I shouldn't be surprised where the 3C5X9CFG utility didnt find it even with absolutely everything else removed or disabled (except for VGA card).

Before truely declaring it dead, I might throw it in the oven for a last ditch effort that DIY reflow might fix something...

Hi, is fuse no. 1 okay ?

Jo22 wrote:

Hi, is fuse no. 1 okay ?

Hm, I thought maybe that was just related to the BNC/ThinNet connector... but I'll definitely check it out tomorrow.

If it is blown though I might be afraid about why its blown... a short on the board I can't see?

Or a grounding problem at some point during this card's life with something on the network

RJDog wrote:

If it is blown though I might be afraid about why its blown... a short on the board I can't see?

So if you fix the fuse and don't see anything else wrong, you can try powering it on in an ATX/ISA machine, soft power button, it shouldn't turn on if there's any shorts, or it will turn on and turn off quick. If it lets the machine boot and there's no magic smoke escapage, then you can put it back in your harder to replace board and try again.

Lightning/surge from the network port. Still happens in old buildings with bad wiring, and still comes in over cable modems during a storm.

Well, it was a good thought, but fuse F1 is good. Following the traces, it seems to be on the 12V line for power supply to the AUI port, so not internal anyway.

I wonder if maybe the ROM/Flash is bad somehow? I also noticed that R10 and R12 underneath the ROM/Flash seem to have their solder points much shinier than all of the other solder points on the board. Not sure if that is meaningful or not... looking at pictures of other 508B-C cards online, the resistors are absent on them as well, so probably not meaningful.

I guess off to the toaster oven... I can't make it any worse, I don't think...

First, make sure the onboard voltage regulator is working.

gdjacobs wrote:

First, make sure the onboard voltage regulator is working.

Yes, it's probably worthwhile to do some live probing on it, make sure voltage is going whee I think it should be going.

Just FYI to the OP and anyone else who cares, my card is brand frickin new from the shrink wrap and it doesn't work with the same symptoms. I don't think the card is defective. Something is up with the ISA's IRQ or port assignment would be my guess. I have a modem blaster in the slot above and it's just fine.

Adding your own problem isn't going to help the OP 😉

This probably deserves its own thread. But in any event:
- what kind of system is this (which motherboard?)
- which OS are you running?
- what other devices are present in the system? And which resources are thet configured for?

I find that ISA PnP is dodgy at best - so the best way to get these cards working is to stick them into an old non-PnP system (486 or similar) with absolutely minimal loadout otherwise (VGA, floppy, nothing more), then run the config util to find the card. Set it manually to something sensible, having done that move it to the destination system, and treat it as non-PnP, so reserve the resources you configured in BIOS and it should work, assuming the BIOS actually does what you tell it and you don't have any other non-PnP devices set to conflicting resources.