Re: My first real attampt to get XTIDE on a network card...struggling some

Posted on 2023-03-28, 21:44

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'll have to get one of my motherboards set up and run dos on it.... I guess. You can run that util using DOSBox too. I haven't tried but I suppose it should also run on 32-bit NT systems via CMD.EXE - just don't try to use any auto-detect functions, pick your options manually. The resulting file ( …

---

Re: Short on +5v rail on DSP-1454NN AT PSU

Posted on 2023-03-28, 11:33

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I will do as you said and start examining the components to the best of my ability. I started with overlaying the pcb solder side over the component side so it will be easier to identify each component from the back. If you are not in a hurry you can wash that PCB in running water. Some solid soap …

---

Re: Short on +5v rail on DSP-1454NN AT PSU

Posted on 2023-03-28, 10:10

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well, now you need to decide if you want to continue or not - because this will not be an easy case and it very well might turn out to be a lost cause (for example a short in the transformer) which is very frustrating (and so can be the investigation into cause quite frankly, although that is at …

---

Re: Short on +5v rail on DSP-1454NN AT PSU

Posted on 2023-03-27, 09:49

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Anyway, with the 100w bulb and the 2 12v bulbs, the voltage on the 5v rail is about 4.4v and on the 12v rail it is about 10.4v... The 100w bulb lights pretty bright. I let the psu rin for couple of minutes but there isnt any change in the voltages or the brightness of the bulb. Hm. I think with …

---

Re: History of Polish computer trade fair 1986-20xx. HD video/hires images from Giełda Komputerowa na Grzybowskiej (1993

Posted on 2023-03-26, 00:04

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

HanJammer wrote on 2023-03-25, 22:00: Whoever uploaded it to Internet Archive - took it from my FB Fanpage https://www.facebook.com/GieldanaGrzybowskiej/ where I published it with exclusive author's son permission. Times have changed. People? Not so much. If they can steal it, even merely for " …

---

Re: OPTI-495SLC 386 WB mainboard fails to POST when powered up but POSTs after reset

Posted on 2023-03-25, 17:23

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have tested the board with another PSU and there seems to be no change. So the power-on reset issue is more probable. But I will try one more PSU just to be sure. PWR_GOOD is the power-on reset signal. If your mobo had a battery spill near power connector then it's possible that trace got …

---

Re: Whats the problem with CRTs? difficult to buy

Posted on 2023-03-25, 13:04

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yup, depends on the country. Also not everybody is interested in late CRTs, I'm not for example. I just let 3 monitors go to junkyard because 17" super VGAs (that have seen plenty of use) is not my thing. I like older mono stuff (green/amber MDA/Hercules) and I'd love to get my hands on working and …

---

Re: OPTI-495SLC 386 WB mainboard fails to POST when powered up but POSTs after reset

Posted on 2023-03-25, 12:55

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It could be PSU fault. PWR_GOOD signal is supposed to have certain delay and pulse length, if it's not in spec mobo might not reset properly. Could also be "tired" chips or marginal filtering capacitors on the mobo, or a combination of both. In general it's not easy to fix (unless PSU replacement …

---

Re: 486 will not boot from floppy; will not read from floppy either

Posted on 2023-03-24, 22:34

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

What do you have connected as HDD in that system? A CF card? Did you try the floppy boot with no HDD of any kind connected? Just in case disconnect any cables and adaptors/sockets as well, leave only floppy drive and it's cable connected.

---

Re: I let the smoke out of a Pro Audio Spectrum 16. Can it be repaired and saved?

Posted on 2023-03-24, 22:31

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It died the instant I put it in. (...) I want to be safe and not break the card any more than I already have. FYI it's not your fault. These older tantalum caps can die like that, especially after a long period (years) of not being powered. Manufacturers test them better these days, reputable …

---

Re: Sharp PC-3100 Palmtop PC - Boot Error - Help Needed

Posted on 2023-03-24, 17:16

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

ArchiMark wrote on 2023-03-24, 17:09: Seemed to go OK, but when it finished and rebooted I got a a strange message on screen. See photo. That looks like a key symbol? It wants some sort of password input I guess?

---

Re: Short on +5v rail on DSP-1454NN AT PSU

Posted on 2023-03-23, 18:44

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The 60W bulb stays lit. Not very brightly, but also not so dim as before I replaced the transistors. I measured the voltage on the 5v and 12v rails, and it is 1.7v and 4v... too low... The efficiency of that PSU, at light load, might be very poor. Go to 100W bulb. It should be even dimmer than 60W …

---

Re: Short on +5v rail on DSP-1454NN AT PSU

Posted on 2023-03-23, 12:42

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yeah. Higher voltage rating is good, it does usually increase the forward voltage drop but only slightly. Just make sure the 3A part has leads thin enough to fit through the PCB holes. Although that is not exactly a difficult problem to resolve, just drill them a tad bigger if necessary. EDIT: Do …

---

Re: Short on +5v rail on DSP-1454NN AT PSU

Posted on 2023-03-23, 12:36

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well, to be frank this is a rather cheaply made PSU. Minimal input filtering - no caps but at least there's a common-mode choke, some PSUs just put 2 jumper wires and do away with that as well. There isn't a thermistor (or at least I don't see it) to limit initial input surge, there is this resistor …

---

Re: Short on +5v rail on DSP-1454NN AT PSU

Posted on 2023-03-21, 20:16

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Found short on diode D4. Took it out and it is indeed shorted on both sides. The other diodes beeped only on one side, and the other showed 0.55 (what are we measuring here actually?) You are measuring forward voltage drop - diodes are not perfect, there is some drop (necessary for the …

---

Re: Dead Slot 1 motherboard A-Trend ATC-6310M

Posted on 2023-03-21, 16:18

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

What does "No fan, no POST card lights, nothing" mean, exactly? POST cards have LEDs for power rails, these also do not light up? Is the ATX PSU starting at all? I would assume, since the 3V3 lines seem to be N/C and the mobo does have AT power connector too which lacks 3V3, that this voltage is …

---

Re: Short on +5v rail on DSP-1454NN AT PSU

Posted on 2023-03-21, 16:09

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That is most likely a short on the primary side then. Let the PSU sit disconnected for 5min then start checking things: 1) diodes D1, D2, D3 and D4 for being shorted, preferably using diode check function in the meter - anything below 0.5V is very suspicious since these are silicon diodes 2) both …

---

Re: Short on +5v rail on DSP-1454NN AT PSU

Posted on 2023-03-21, 14:23

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That looks good.

---

Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Posted on 2023-03-21, 14:01

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Landmark FPU score would start out high, around 200, then slowly drop over the course of a minute or two, to around 145. I've seen that on 386DX CPUs as well. I have a mobo that scores a tad bit higher in floating point than other ones, but it's very picky about CPU and NPU pairing. Even hangs with …

---

Re: Short on +5v rail on DSP-1454NN AT PSU

Posted on 2023-03-21, 12:49

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Can you elaborate on that? Where do I need to connect the bulb? on the main cable? This PSU has an output for connecting a monitor, can I use it to attach the bulb? Yes, on the mains cable. Assuming L is live and N is neutral (although it doesn't matter if it's in reverse): * Wall socket L -> cable …

---