Re: Homemade ICs may become real

Posted on 2019-12-28, 12:09

by

by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

FPGAs and CPLDs are still the way to go in my book... I can replicate a whole vintage system, hardware-accurate (with space to spare) in a medium-size FPGA for under $100. Keep in mind that FPGA/CPLDs can only replicate digital chips, not mixed analog-digital chips. Some computers have ICs that are …

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Re: Homemade ICs may become real

Posted on 2019-12-27, 22:41

by

by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

FPGAs and CPLDs are still the way to go in my book... I can replicate a whole vintage system, hardware-accurate (with space to spare) in a medium-size FPGA for under $100.

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Re: Welcome to the updated VOGONS

Posted on 2019-12-27, 22:36

by

by stamasd

in Milliways

in Milliways

My eyes! My eyes!

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Re: DIP-14 OSC replacement with jumpers?

Posted on 2019-12-24, 17:58

by

by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Those pictures are tiny and I can barely distinguish the schematic but it looks like a RC oscillator. While that will work it won't have the stability of a quartz PLL generator. These are thumbnail pictures, they open when clicked. They are not clickable for me. It may be a feature only for users …

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Re: DIP-14 OSC replacement with jumpers?

Posted on 2019-12-24, 15:18

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by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

You might like my simple circuit that I built to generate clock from a few hundred kilohertz to >66MHz. It works like a charm. Clock speed is adjusted the most simple way I can think of: setting clock by just turning a potentiometer until the built-in frequency counter LED display indicates the …

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Re: Boxed goodies: ISA, PCI, and AGP cards

Posted on 2019-12-20, 20:36

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by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The CT2230 is a good card, I have one.

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Re: Yet another slotket question!

Posted on 2019-12-20, 13:28

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by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Oh, so the voltage regulator has nothing to do with it? What is it there for? I don't know if I can lower the voltage from 2.00v in my motherboard. Is there any danger of breaking something if I test different chips? Neither of your slotkets has any VRM on it. The first one jas jumpers that simply …

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Re: Moving: How to safely and efficiently pack hardware

Posted on 2019-12-20, 13:18

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by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I hate moving (I've done it a lot, but thankfully not for the past 10 years). Most of my hardware is stored in plastic storage boxes, the kind with locking lids. I keep them packed all the time except for 1-2 systems which I have out and working at a time due to lack of space. The boxes are packed …

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Re: Roland SC88VL problem

Posted on 2019-12-20, 13:05

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by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I guess 2 things can be tested: 1. compare his dump to the one I posted above which is from a known good unit 2. if the same or very close, burn either of them in a 27C4096 and install that in the PROM socket, see if that fixes the problem. But it's possible that there is a problem somewhere else on …

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Re: Roland SC88VL problem

Posted on 2019-12-20, 00:58

by

by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Cool. Keep us posted, just in case some day I get to deal with the same problem I'll have a reference. 😀

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Re: Roland SC88VL problem

Posted on 2019-12-18, 23:02

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by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Okay it worked. I've dumped it as HN27C4096. See attached. You should have no trouble to burn that into an 4096 chip.

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Re: Roland SC88VL problem

Posted on 2019-12-18, 22:24

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by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have a SC88VL but I have never opened it; I have a TL866 also. If I have time in the next day or two I'll try to dump the eprom. (edit) The chip is socketed, right? I wouldn't want to have to desolder/solder a 40pin DIP. :) Also the HN62444B is not in the list of supported chips for the TL866, but …

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Re: DIP-14 OSC replacement with jumpers?

Posted on 2019-12-18, 14:17

by

by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

FWIW I ordered some parts from OnSemi; the NB3N511 is currently out of stock in their sampling program and will take a couple weeks, but I have already received another part https://www.onsemi.com/products/clock-timing/clock-generation/pll-clock-generators/fs6370 https://www.onsemi.com/pub/ …

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Re: Bought these (retro) hardware today

Posted on 2019-12-16, 13:26

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by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Ouch. Sometimes a reflow using the oven or reflow station would suffice. I've thought about it; the problem is it has BGA memory chips on both sides of the card. (not my pictures but it looks exactly the same) http://scusatrading.com/images/products/detail/2014.03.24016.JPG http://www.technodirect. …

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Re: Bought these (retro) hardware today

Posted on 2019-12-15, 18:24

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by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Bought a Quadro FX 1100 AGP video card (equivalent of a Geforce FX 5800). However when I received it, a quick inspection showed that the fan was not spinning when pushed by finger - it was jammed. Not having great expectations after that I plugged it in anyway and was greeted with this screen: …

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Re: CT3670 RAM socket repair

Posted on 2019-12-15, 16:14

by

by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Another suggestion I would make: the extra solder you add should be a low-melt temperature solder like this one: https://www.digikey.com/product-detail/en/chip-quik-inc/SMDIN52SN48/SMDIN52SN48-ND/8681827 Not only it stores heat, but also it stays liquid until it reaches lower temperatures compared …

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Re: CyberNet Elite-4i Zero-Footprint-PC adventures

Posted on 2019-12-13, 21:53

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by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

If you could find something like this flexible PCI riser slot extender ribbon cable adapter expansion card that has female connectors at both ends, that would be ideal. I didn't find any.

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Re: CyberNet Elite-4i Zero-Footprint-PC adventures

Posted on 2019-12-13, 20:59

by

by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Very cool find. But maybe I'm blind - I don't see where a PCI riser would go. (edit) yup I'm blind now I see it. I have a full case of PCI connectors NOS, if you need one (or a few) to make a custom riser just ask.

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Re: DIP-14 OSC replacement with jumpers?

Posted on 2019-12-13, 20:26

by

by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Looks like a 25MHz crystal divided by 3 would give the most useful range of frequencies (8.33 to 66.6MHz). Here's BTW a divide-by-3 circuit with 50% output duty cycle with 3 D-flipflops and 3 NOR gates (one used as an inverter to change the phase of the clock for the 3rd flipflop): https://1.bp. …

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Re: DIP-14 OSC replacement with jumpers?

Posted on 2019-12-13, 15:40

by

by stamasd

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There's also this https://www.onsemi.com/products/clock-timing/clock-generation/pll-clock-generators/nb3n3020 which takes a 5-27MHz crystal and offers 26 selectable multipliers from 1x to 16x with 3 selection pins (max 210MHz). This is only a 3.3V device though so it will need voltage conversion …

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