Re: Epox EP-58MVP3C-M - 3.54v Vcore regardless of jumpers

Posted on 2025-06-11, 03:13

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Remote troubleshooting like this is difficult, especially when what appears to be the controller has no known public datasheet and the same part number as an extremely common Atheros USB WiFi chip. It still feels like it isn't detecting the multi-voltage CPU correctly, but it's hard to say without …

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Re: Anyone else use their machines for productive things?

Posted on 2025-06-07, 20:59

by

by lti

in Milliways

in Milliways

I was using a Pentium II laptop to type papers in college, and I graduated in 2015. There's something magical about those old laptop keyboard, isn't it? FWIW, my college laptop (2010-2015) was a Pentium 3 Dell Latitude C600. I did a lot of my typing on it... though not anywhere as much as on my …

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Re: Epox EP-58MVP3C-M - 3.54v Vcore regardless of jumpers

Posted on 2025-06-06, 03:00

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I meant that the OUT pin would connect to the AR7010 (after the resistor and transistor you found). I would also expect a connection from the R1P transistor to Q9.

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Re: Anyone else use their machines for productive things?

Posted on 2025-06-04, 04:33

by

by lti

in Milliways

in Milliways

I was using a Pentium II laptop to type papers in college, and I graduated in 2015. I bought a new laptop for college, but it was the one I made a ridiculously long post about in the "hardware you wish you'd never bought" thread . The big problem was the keyboard only lasting three months, but I …

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Re: Epox EP-58MVP3C-M - 3.54v Vcore regardless of jumpers

Posted on 2025-06-01, 19:15

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The COMP voltage changing means that it is part of the feedback for the VCC2 (Vcore) supply. The output should eventually connect to the AR7010 after going through some other parts (probably just some resistors). Drawing the circuit as you go (including all connections to VCC2DET) might help. Were …

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Re: What retro activity did you get up to today?

Posted on 2025-06-01, 17:08

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I got a Windows 98 VM running under Linux using QEMU and virt-manager. Does that count as modern or retro? What wasted the most of my time was trying to figure out why the audio and network adapters weren't detected and the DMA option didn't exist for the hard drive. I eventually figured out that …

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Re: SATA to IDE adapters

Posted on 2025-05-31, 18:30

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It was on the chip. Also, I was using it in a laptop, where the PDIAG pin on the IDE connector was never connected to anything. It's designed so the IDE controller always thinks an 80-conductor cable is used because there's no cable at all.

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Re: SATA to IDE adapters

Posted on 2025-05-31, 17:52

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

You can also increase the speed in hardware. If you apply GND to the 46 pin of the B76ZZ0041 chip. Is that chip pin-compatible with the JM20330? If it is, pin 46 is PDIAG, and grounding it on my JM20330-based converter didn't change anything. I even tried connecting the FXDMA pin to 3.3V and …

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Re: Epox EP-58MVP3C-M - 3.54v Vcore regardless of jumpers

Posted on 2025-05-31, 15:50

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

What voltage do you see on the input pin? It might be part of the feedback to the mystery controller (in the same part of the circuit as the voltage selection jumpers). It's weird to ground the output, so there must be a resistor in series with the input to limit the current. I still don't see why …

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Re: SATA to IDE adapters

Posted on 2025-05-31, 01:48

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have a SATA to Slim IDE 50 adapter based on the B76ZZ0041 chip. On Linux (Lubuntu), it works in UDMA6 mode with the setting libata.force=80c. On Windows 7? Unfortunately, only UDMA2. The southbridge is VIA VT8235. Note that on Linux it operates in UDMA6 mode through the Slim IDE connector (!!!), …

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Re: Epox EP-58MVP3C-M - 3.54v Vcore regardless of jumpers

Posted on 2025-05-31, 01:41

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There are all kinds of other VRM controllers on socket 7 boards that you can look at to try to understand what's happening. There's even this thing that forces a shunt regulator to oscillate . Both Vcore pins on my AR7010 are connected together (0 ohms). It's a really strange-looking layout then. I …

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Re: Epox EP-58MVP3C-M - 3.54v Vcore regardless of jumpers

Posted on 2025-05-29, 04:19

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm actually thinking that pin 8 (the pin you marked blue) is the PWM output, and the group of parts between the AR7010 and the diode at Q12 (they used the wrong designator prefix) is the gate drive circuit. I found the datasheet for the US3033, and it's completely different. Here's a link to one of …

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Re: What modern activity did you get up to today?

Posted on 2025-05-27, 04:13

by

by lti

in Milliways

in Milliways

I need to switch VM software. VirtualBox randomly crashes with the same segfault (blaming different CPUs every time, but otherwise identical text in dmesg), but only when the VM is left idle (not the active window) for a long period of time. I can find people getting similar segfaults immediately …

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Re: Epox EP-58MVP3C-M - 3.54v Vcore regardless of jumpers

Posted on 2025-05-27, 01:08

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm thinking there is a problem with the circuit connected to VCC2DET. Since there is no schematic, you'll just have to follow the traces to see where the feedback jumpers connect. I'm guessing that there is a small transistor (most likely a 2N7002 FET) to bypass the jumpers if VCC2DET isn't …

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Re: Power Supply Capacitors

Posted on 2025-05-26, 21:45

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Higher voltage caps will be larger, so they might not fit. That's the only problem with increasing the voltage rating. I wouldn't buy caps off Amazon, but increasing the voltage rating might help cheap (with a ridiculous markup that might exceed the shipping cost from a major distributor) or …

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Re: Epox EP-58MVP3C-M - 3.54v Vcore regardless of jumpers

Posted on 2025-05-25, 23:32

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There is a VCCDET pin that needs to be shorted to ground to make the VRM output both voltages. It's floating (not connected to anything) on a single-voltage CPU and grounded on dual-voltage CPUs. 3.54V is a little high for a single-voltage Pentium (it's normally either 3.3V or 3.45V), but that might …

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Re: What modern activity did you get up to today?

Posted on 2025-05-23, 19:51

by

by lti

in Milliways

in Milliways

Meanwhile, I'm on 12/1. I should check fiber availability again, but I seem to live in an area that's even more screwed than usual in ISP choices. There were two votes for municipal broadband (one being over 10 years ago and the other being in the last local election), and this town is the only …

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Re: Found an Ensoniq Soundscape Elite... but it's corroded!

Posted on 2025-05-18, 23:19

by

by lti

in Marvin \ Sound

in Marvin \ Sound

unfortunately I can't check the capacity of the capacitors C90 and C99, but they all have the same marking, A2 and A5. You can unsolder them and measure them. They may all be the same. According to this , the marking code A2 is 1nF (1000pF) and A5 is 0.1uF. Someone can desolder them and verify. C79 …

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Re: The quest for the perfect retro laptop: a saga

Posted on 2025-05-17, 02:59

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

If it's ABS you can chemically weld it with Methyl Ethyl Ketone (MEK) or acetone (takes longer to dissolve) and make repair cement with ground ABS in either of those. I've found that MEK usually doesn't work well at all on this old brittle stuff. It can work well on newer plastics that are still …

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Re: Are these KZG caps bulging from the bottom? - Asus P5GD1 Pentium 4 socket 775 board

Posted on 2025-05-11, 23:29

by

by lti

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Seems a good deal of former BCN members have "flocked" to this place. Not sure if it's because of interest in retro PCs (which doesn't seem to get that much attention there anymore) or the forum update. For me it's a little bit of both, I suppose. Though I only discovered VOGONS a little over a …

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