Re: Troubleshooting a Juko Nest Baby XT board

Posted on 2016-04-30, 17:41

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm attaching my guess at the banks. Not sure if the 128k bank must contain something. Depends on which block starts at address 0. If you have a piezoelectric speaker (no conductivity across it) you can try every header without danger. So the 8088 is not held in reset and may be executing code. …

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Re: Troubleshooting a Juko Nest Baby XT board

Posted on 2016-04-30, 15:54

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes, it is repeating, I haven't seen that. For a 2764 chip use only one half. Speaker: One pin should have 5V, the other may go through a resistor (like 33 ohms) to the collector of that transistor. What does the documentation of the POST card say about '--'?

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Re: Troubleshooting a Juko Nest Baby XT board

Posted on 2016-04-30, 15:21

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The JUKOVEGAS.zip should be correct. 16k -> the EPROM will be a 27128 then. The output of POST codes depends on the BIOS, it's possibly not implemented or goes to a different port. As the BIOS works in another board you could check what the POST card does there. About the 48 ohms: The power supply …

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Re: Investigating The ISA 8bit OCTEK UM587F VGA card.

Posted on 2016-04-27, 20:29

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Electrolytic is no problem (aside from aesthetics). Secret hint: GND is on the slot cover - easier to stick the prober there.

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Re: Investigating The ISA 8bit OCTEK UM587F VGA card.

Posted on 2016-04-27, 18:14

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

> bridging +5V and -12V I don't think so. These capacitors are GND relative. If you find both -12V and +5V shorted to GND then probably two capacitors are shorted. Did you unsolder the capacitor to test? If not, it can still be anything else on the card that is shorting as most components are …

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Re: Schneider Euro PC

Posted on 2016-04-24, 20:46

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

As this is a pure digital chip you will need external cirquity. CSYNC will mean composite sync. With luck, the other is a chroma output. You could check that with an oscilloscope. If it is, you can do a mod as I've done for this V6366-based LCD CGA. It is basically the cirquit you find on an IBM …

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

Posted on 2016-04-24, 19:13

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The Trident chips could already have the LM339 integrated. But even if not the tool may be able to get back the color. It switches the video BIOS to color monitor. If it does help, one can add it to autoexec.bat.

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

Posted on 2016-04-24, 18:41

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

> but it only outputs monochrome Investigating old ISA VGA cards

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Re: Getting CD Music to work in DOS

Posted on 2016-04-23, 16:39

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

You still didn't bother to write what kind of laptop you have so we could know what sound solution it has...

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Re: i387SX manufacturing date codes help...

Posted on 2016-04-23, 16:31

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It's the internet, nothing is safe 😁

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

Posted on 2016-04-23, 16:23

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

If anyone can think of any other reason for a card hindering a PSU that is powered on with a f*****g live mains switch from powering on other than beeing one big short please let me know. :) A tantalum cap may have shorted. Did you check the solder side for shorting pins? You can also remove many …

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Re: A silly question about sound card capacitors

Posted on 2016-04-23, 16:11

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

> how do I know if capacitors and chips are missing by design and not because someone decided to strip the card? In the latter case you usually see remainings of solder. Sometimes there will also be a huge mess and damage done... > It's just so weird to me they didn't assign this a different model …

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Re: i387SX manufacturing date codes help...

Posted on 2016-04-23, 10:50

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

http://www.cpu-world.com/forum/viewtopic.php?t=23815

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Re: Need help identifying multi I/O and a sound card

Posted on 2016-04-22, 22:12

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The ECP/EPP cards tend to come in ISA-16bit and highly integrated (not many chips on board).

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Re: Getting CD Music to work in DOS

Posted on 2016-04-22, 17:00

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

> I've got an old laptop ... what kind of laptop...

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Re: Need help with a small issue regarding soldering in a new BIOS battery.

Posted on 2016-04-20, 19:33

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

http://www.powerstream.com/p/Lir2032.pdf So it's a small sister of the notebook battery 'hand grenades'. It should not be charged above 4.2V and discharged below 3V.

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Re: Need help with a small issue regarding soldering in a new BIOS battery.

Posted on 2016-04-20, 18:55

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Strange package for a 3.6 volt rechargeable battery...

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Re: Advice needed; Notebook screen issues

Posted on 2016-04-20, 18:49

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

As this is not a high-current application I wouldn't bother with lowest possible ESR - the replacement should be 105°C rated for a long life and match in size. I.e. this one should be a candidate: 647-UCL1V220MCL1GS Or you wait for advice from the people here who know each capacitor personally 😉.

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Re: Need help with dead CRT

Posted on 2016-04-20, 16:53

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The better the detail photos the more help... Hope you have at least a multimeter.

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Re: ESS Solo1E DOS audio mixer?

Posted on 2016-04-19, 18:30

by

by h-a-l-9000

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Say your soundblaster port is 220h. - write 3Ch to 224h. - write 00(loudest)-07h to 225h. in debug: o224 3c o225 07 Worth a try 😀 But I'm afraid whenever a game resets the mixer this change is gone.

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