Re: Advice for good soldering workshops in the Netherlands, preferably in the Amsterdam area?

Posted on Yesterday, 22:29

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Can any of you maybe recommend any good workshops for people who wish to gain more experience with soldering, tailored towards hobby electronics, including retro computer hardware tinkering? Consider YT videos. Some are great, some not so much, but it's free and you can pick a teacher and lesson …

---

Re: Intel Pentium prototype?

Posted on Yesterday, 21:59

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That thing shouts fake to me. Or perhaps it is some sort of memento, made way later out of dead chips. I haven't worked at Intel, or designed any chips, but I've seen prototypes. You do not put a logo and other brand markings on a prototype. Laser engraved serial on the package - maybe. But no …

---

Re: Fixing CT-6BTM0 motherboard - C0, C1 and then ambulance alarm

Posted on 2024-06-03, 18:59

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The cheapest ATX extension cables from china are using below-standard wire widths! 18AWG should be standard so make sure your extension cable is at least that. That reminds me that I bought a pack of breadboard connection wires and for some reason my contraption didn't work properly. Turns out the …

---

Re: Pc power and cooling power supplies

Posted on 2024-06-02, 23:52

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

starter capacitor, those commonly go out on things like HVAC units after about 5-10 years Apples. Oranges. Oil AC capacitors die because of the working conditions - direct connection to noisy line with all the voltage spikes. Then there is heating, both external and internal - there will always be …

---

Re: Cyrix 5x86 on older 5V-only 486 motherboards

Posted on 2024-06-02, 15:37

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It's pretty amazing (...) You seem to have misspelled "cheap" :) I always wondered how many of these mobos were using licenced, actually paid for, BIOSes. IIRC there were some no-name mobos that just stole the BIOS off some other product (it was a clone so little to no work needed, other than some …

---

Re: Pc power and cooling power supplies

Posted on 2024-06-02, 11:34

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I never had any issues with PC PSUs until AMD Athlon/Duron era. At this point the local market was flooded with cheap, nasty Chinese inventions that had ever higher W/A numbers but the insides were more and more "optimized" for mass production. I actually had 2 or 3 go bang on me in the summer, and …

---

Re: Fast Ethernet on ISA

Posted on 2024-06-01, 18:44

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've run some Linux benchmarks. Results from my K6-2 system convinced me to try some synthetics as well. Conclusions so far, in no particular order: * I tested only early Debians (Buzz and Potato), with kernels 2.0.36 and 2.2.26 - it's very unlikely I'd be using ISA network cards with anything newer …

---

Re: Do you always open and clean newly acquired CRT? My experience...

Posted on 2024-06-01, 17:54

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I like my CRTs clean. Especially the pre-owned ones, since I have no idea who used them and for how long, I don't want all that stuff wented out with hot air into my lungs. It also simplifies repairs, clean PCB is much easier to work on, not to mention being able to spot obvious issues right away.

---

Re: Seagate ST-157A

Posted on 2024-05-30, 09:10

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

No, I meant replacing the burned out element in red circle with a wire, since it was most likely a choke and you won't be able to guess now what particular value it had (probably a few uH). Well I suppose you could try to use thinner wire that would be like a fuse but that is a lottery. Too thick …

---

Re: Cyrix 486DLC-40 with Cyrix Fasmath 83D87-40-GP Benchmarks

Posted on 2024-05-28, 15:10

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Not 100% sure what "Cyrix optimization sw" is, I assume the internal cache control program? You are still being held back a bit by lack of Write-Back mode in mobo cache. In Lanmark 6.0 I get 168 MHz AT, 164 MHz 80287, 5146.81 chr/ms. 65.7 in Norton SI 8.0, 6.2 in PC Player Benchmark 320x200 mode. …

---

Re: Dead p2-450?

Posted on 2024-05-28, 14:39

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I did manage to get it to show some post codes (can't recall what) but haven't been able to reproduce it. On this mobo or known good one? Because it could be a slot issue, these are not very robust - I have heard stories about bad slots. Usually issues developed by twisting the CPU too much, …

---

Re: Dead p2-450?

Posted on 2024-05-28, 13:08

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That's a flip-chip design IIRC, such a tiny piece missing on what is the back of the substrate shouldn't really kill the CPU. Clean the gold pads with IPA, make sure you have good contact in the slot.

---

Re: Seagate ST-157A

Posted on 2024-05-28, 13:03

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I think the capacitor is shorted and caused the SMD in front of it to burst Most likely a choke then but do make sure, if putting a piece of wire across the pads doesn't short the power connector then it's pretty safe to test the HDD with this "fix". After you replace the cap the blew up of course, …

---

Re: Fast Ethernet on ISA

Posted on 2024-05-28, 10:09

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Still, be careful - the slowdown resulting from duplex mismatch may be moderate on a quiet network, but much heavier when the network gets busy. I'll think about how I could simulate such a thing. Unless I use coax there will always be somewhat modern store-and-forward network switch isolating that …

---

Re: Fast Ethernet on ISA

Posted on 2024-05-28, 09:00

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

A synthetic test would probably give me more clear-cut results (I will try something like this with Linux test) but then again if I see no difference in a test that is my typical use case then why would I worry about the FD setting? It's not like I'm trying to squeeze the last bit of the performance …

---

Re: Seagate ST-157A

Posted on 2024-05-28, 08:35

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The only caps big enough to have both value and voltage rating printed on them are the tantalums, and there is one 4u7 25V on the PCB. Black, next to crystal resonator and the power connector nearby. Assuming it's this one, which particular SMD in the area burned? If anything I would assume it's the …

---

Re: Fast Ethernet on ISA

Posted on 2024-05-27, 18:55

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've decided to run some tests on my cards. Reason being I also have 3C509 non-B that I wanted to benchmark against B model in DOS. So far on 486DLC-40 and DOS/MTCP + packet driver I can't really see much difference between HD and FD modes. In fact if anything the FD mode seems to be a tad bit …

---

Re: AMD 386DX-40 with Cyrix Fasmath 83D87-40-GP Benchmarks

Posted on 2024-05-27, 16:14

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Grzyb wrote on 2024-05-27, 13:43: ULSI FPU is obviously faster than Cyrix. That depends on what you are doing with it. Basic math operations? Yeah, ULSI will finish first. Calculating trigonometric functions? Cyrix wins, and by quite some margin too.

---

Re: AMD 386DX-40 with Cyrix Fasmath 83D87-40-GP Benchmarks

Posted on 2024-05-26, 20:29

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

PiotrUU wrote on 2024-05-26, 14:46: an additional cache chip (U32) slightly increases performance. Ah, so that's what gave me a higher score- cache in WB mode. Good to know, I was considering buying another Cyrix '87 for testing and now I can avoid getting the exact same chip I already have.

---

Re: XT-IDE site dead?

Posted on 2024-05-26, 20:10

by

by Deunan

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I visited there a few days ago and while the site was up I had terrible page load times. Some would even time out and I had to retry a few times. I was looking for some info on what exactly is compiled into 386 code, both l and non-l, didn't really find much on that subject. The latest version is …

---