Re: Smoke coming from PAS16

Posted on Today, 08:46

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by mkarcher

in Marvin \ Sound

in Marvin \ Sound

If VD is taken from +5V and VA is taken from +12V using a regulator, there should be no really low impedance path between VA and VD. If you see less than 5 ohms between VA and VD, and you also see VA is coming from the 7805, something that is connected to both VA and VD might have an internal short …

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Re: MoSys vs EliteMT memory (Riva 128ZX) 1998 VGA

Posted on Today, 08:36

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I need to figure out how to recognise which is which Memory Type: SGRAM, SDR Get a photo that is good enough to read the marking of the memory chips, then put the marking into a search engine to find a datasheet. "SDR memory supports only in 64bit mode, so bandwidth is only 800MB/s." If that's true …

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Re: MoSys vs EliteMT memory (Riva 128ZX) 1998 VGA

Posted on Yesterday, 21:08

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Very helpful and informative. So you recon MoSys would perform slighly better in 3D Win9x ? I think it is likely, but not guaranteed. I neither know the specifications of the specific MoSys chips used on that card, nor know at what specifications the SDRAM on the EliteMT card is actually operated …

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Re: Starting up a new Dallas RTC chip

Posted on Yesterday, 20:57

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I didn't realize these took +5V, but in the datasheet they do. I believe we have all noticed the following behavior: on a barrel battery board, the board will hold the settings across reboots (because of the charging circuit) and even after the board is powered off for an hour or so (because of …

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Re: Tube Time: Announcing The Snark Barker, a 100% Compatible SB 1.0 Replica!

Posted on Yesterday, 20:36

by

by mkarcher

in Marvin \ Sound

in Marvin \ Sound

It’s weird when I run the test And I checked the version sometimes I’ll get 1.02 and sometimes I get 2.01 so something funky either with the test or the DSP chip itself If you sometimes get the wrong version number, the interface between the ISA bus and the DSP is obviously not working reliably, or …

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Re: MoSys vs EliteMT memory (Riva 128ZX) 1998 VGA

Posted on Yesterday, 20:13

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

My choice have to be made between Gainward Riva 128 ZX and CardExpert which has Mosys. Which would you choose and why? I've seen also MoSys memory chips on Tseng ET6000 PCi which is great for DOS. The ET6000 is famous for using a very special RAM type, that AFAIK has only been mass-produced by …

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Re: Tube Time: Announcing The Snark Barker, a 100% Compatible SB 1.0 Replica!

Posted on Yesterday, 19:56

by

by mkarcher

in Marvin \ Sound

in Marvin \ Sound

also, the DSP doesn't appear to be connected to the SAA chips in anyway. those should be completely independent correct? If I remember correctly, the SAA chips are quite slow and accessing them is supposed to generate wait-states on the ISA bus using the IOCHRDY line. If your system locks up as …

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Re: Starting up a new Dallas RTC chip

Posted on Yesterday, 19:53

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

so doing some hack to change the "storage" or "low power" mode (honestly looking at the chip data sheet and what is actually inside a Dallas RTC, I think this is not really a thing Would you please reconsider the claim that there is no "low power" mode after looking at the datasheet at https:// …

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Re: Matrox MGA G450 Dual Head does not work on Lucky Star LS-486E (SIS 85C496-7)

Posted on Yesterday, 19:30

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I don't know whether I've seen that card working on a SiS 496 yet, but I know a system based on the UM8881 with that card. It works fine at PCI@33MHz, it refuses to correctly intialize at PCI@20MHz, and requires a heatsink on the HiNT/PLX bridge chip at PCI@40MHz. On the UMC chipset, the PCI/FSB …

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Re: Anyone know what this ISA card is for?

Posted on 2024-05-22, 17:00

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The EPIC chips are 16C552 chips, which are dual 16C550 chips. Those are serial UARTs. This card is a 4-port serial card. Two serial ports are on the 37-pin connector, and the other two on the two 26-pin pin headers. For the 37-pin connector, you need a break-out cable that converts it into 2*25-pin …

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Re: Anyone know what this ISA card is for?

Posted on 2024-05-22, 13:00

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

According to that product page, this thing has 4 serial ports and 2 parallel ones. No drivers required. Thanks for the extra research. I somehow missed the fact that the 16c552 also includes a parallel port. This changes my claim about the connections: The two internal connectors are likely the two …

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Re: Anyone know what this ISA card is for?

Posted on 2024-05-22, 05:09

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The EPIC chips are 16C552 chips, which are dual 16C550 chips. Those are serial UARTs. This card is a 4-port serial card. Two serial ports are on the 37-pin connector, and the other two on the two 26-pin pin headers. For the 37-pin connector, you need a break-out cable that converts it into 2*25-pin …

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Re: What are the DOS games that have problems if you have more than 16MB of RAM installed?

Posted on 2024-05-21, 18:18

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by mkarcher

in Marvin \ Software

in Marvin \ Software

Pinball Fantasies crashes on startup. Strange, I've never encountered such problems. And it seems to only use conventional memory, refusing to run if too many drivers/TSRs are loaded. Why would it even care about extended memory? There are different versions of Pinball Fantasies. Most notably, GOG …

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Re: Starting up a new Dallas RTC chip

Posted on 2024-05-21, 17:51

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

This post explains how to put it into "storage" or "low power" mode: https://www.vogons.org/viewtopic.php?f=46&t=64819&p=728135&hilit=dallas%20rtc#p728135 Can someone tell me how to wake them back up? The only thing that is turned off in "storage" / "low power" mode is the clock. The data storage …

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Re: Smoke coming from PAS16

Posted on 2024-05-20, 10:43

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by mkarcher

in Marvin \ Sound

in Marvin \ Sound

These connections to GND and Vcc on the card seem intended and make sense. So just to clarify, 30 ohms between 5v and GND may be normal with this card? That's not what I meant with "seem intended and make sense". I referred to the high amount of chips being "shorted" to GND and Vcc. 30 ohms between …

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Re: Smoke coming from PAS16

Posted on 2024-05-20, 00:06

by

by mkarcher

in Marvin \ Sound

in Marvin \ Sound

Don't forget though the primary fault was the original chip blowing its top, so the replacement acting the same isn't a strong indicator for it being fake. Good point. Possibly the chip misbehaves (and might self-desctruct) if one of VA (supply voltage for the analog section) or VD (supply voltage …

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Re: CRT Terminator Digital VGA Feature Card ISA DV1000

Posted on 2024-05-19, 12:48

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by mkarcher

in Release Announcements

in Release Announcements

Actually you might be able to answer a question on video signal. I'd like to use this with a lovely 4:3 beige LCD, which does 1280x1024 @ 75hz. But only has a VGA input. Why would you use the CRT terminator if you need analog VGA input anyway? Is the quality of your VGA card that bad that you hope …

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Re: Smoke coming from PAS16

Posted on 2024-05-19, 07:06

by

by mkarcher

in Marvin \ Sound

in Marvin \ Sound

It does sound like the chip is operating in the wrong mode, with one or more of the multi-function pins operating as outputs when they're intended to be input only. But that's probably just a symptom of VCC being almost shorted to GND; I'd say there's still more bad caps to be found. Another …

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Re: Smoke coming from PAS16

Posted on 2024-05-19, 05:15

by

by mkarcher

in Marvin \ Sound

in Marvin \ Sound

I checked the IC pins for shorts. The following pins were shorted together 29,30,31,33,34,35,36. I thought maybe my soldering had done that so I removed the IC and tested the traces on the board and to my surprise they are still all shorted together. Looking at the PCB photo, I see all of these …

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Re: Schneider Euro PC

Posted on 2024-05-18, 18:23

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I think the problem with monochrome is that my machine outputs 49Hz signal in text mode, and my philips pro 7BM743 cannot sync to that signal. It syncs to 50Hz signal in hercules games though. Hmm, that's interesting. An original MDA card uses a 16.257MHz crystal, whereas the Hercules Card, and …

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