VOGONS


First post, by RubDub2k

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Hi everybody,

I received this P5-90 for free the other day, and was excited to try and get it up and running. For clarification, I'm a bit on the younger side and haven't really dealt with many PC's this old, so I apologize if some of my questions may seem simple.

The computer initially booted fine (seemingly) aside from warning me of a dead clock battery (it has one of those dallas ds12887 chip batteries), so I thought I'd order a coin cell replacement adapter and clean the computer in the meantime. However, following my cleaning of it (removing the dust primarily), I found the computer began to only intermittently display a video output. Sometimes I'd get picture and it would give me the battery warning, other times I'd get no video signal whatsoever. The PC always "turned on", with the HDD light flashing briefly (no HDD in it at the moment), and the power light would remain on, alongside the front intake fans blowing. However, when connected to a monitor, I'd occasionally get no video. I also noticed that sometimes the CD rom tray would not eject either, inspiring me to think that perhaps the power supply was the issue (the original owner that gave it to me had cut one of the floppy power cables off of the power supply for some reason...).

So, I ordered a replacement PSU (that being a used one off of ebay identical to the old one, an "Astec SA145-3435"). However, upon installing the replacement, I found that I no longer get any video out. CD ROM always ejects fine now, HDD light always briefly flashes, intake fans always spin up, but no picture. I checked both the memory (Two 32MB sticks) and video card (a PCI ATI Mach64 dated from 1994, not sure how many MB of video memory or other specs) in another computer I received from the same guy (which had a Gigabyte GA-586ATS board), and both the RAM and video card had no issues... I also tried reseating the CPU and removing any other cards in the system (there were 3 other cards, what seemed to be an ethernet card, a controller card for a tape deck that's also installed in the computer, and a modem card I believe) but didn't see any improvement

So, I guess I wanted to ask if anyone else has had similar issues with these mid-90's gateways, and what you all think the problem may be? Do you think I got another bad PSU? Is there some other problem perhaps I'm not thinking of? I don't think the bad Dallas battery chip would keep it from booting, but I guess this is hardware that's out of my current scope of knowledge. I'd really love to get this computer up and running, so any advice on what to try to do next to troubleshoot would be greatly appreciated. Thanks all,

- RubDub

Reply 1 of 3, by sp3hybrid

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I have a Gateway P5-166 which didn't post because of a bad "power good" signal from the power supply. That is likely not the case for you since you already tried a new supply. However I recommend getting a POST card which are still available new for cheap and checking if the computer comes out of reset and shows post codes (and which ones). A bad Dallas keeps some machines from booting but not from posting so that should not be the issue. When it doesn't post, do you get any beep codes?

Reply 2 of 3, by RubDub2k

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No beep codes... what should I look up to find these POST cards? I've not heard of these before (not too familiar with pre-2000 PC's unfortunately being a bit younger)

And to clarify, the supply I bought was a used supply from a seller online and was relatively cheap... they listed it saying last time it was used it worked fine, but wasn't guaranteed to work 😒

I don't recognize the design of the power connectors to the motherboard, I've really only dealt with ATX power supplies, so I'm not sure if this is a different kind of power supply format or just something proprietary with Gateway. If it is a different format of connector and not proprietary, then maybe it might be worth it to investigate using a different model of power supply?

Reply 3 of 3, by sp3hybrid

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The post card you should be able to get from your online retailer of choice. They are still sold new for cheap. Look for Post Analyzer card. They have a 4 digit 7 segment display which will show the progression of POST codes as the computer boots. They have a ISA and a PCI connector. Be careful on the ISA connector since you can plug it on the wrong way.

The power connector in your picture is a standard P8/P9 AT Power connector. When both are connected to the motherboard side by side make sure the black ground wires (there are two on each connector) are next to each other in the middle. It is possible to swap them around and they will still plug into your board which would be bad.

Without a post card and with the CPU removed you could check the CPU voltage and reset signal with a multimeter from the CPU socket. You can find the pin out diagram online. You can use a realtor lead or similar to fit into the socket. You should get 3.5V for CPU voltage (Vcc). The reset signal should for to 3.5 V briefly when first powered on and then go to 0V short there after. If you have a oscilloscope you can check the frequency pin. This should be the FSB frequency which for a P90 should be 60Mhz I believe. Independent of anything else on the board, the above most be present for the system to POST (or at least start to).