Re: My Fox II blew a cap!

Posted on 2018-05-13, 18:16

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Deksor wrote: I'd say, replace ALL of them since there are many dead ones, who knows how long the remaining ones will still last ? Better buy all of them in a row That's what I plan to do. However they are coming off very hard. Any desoldering tips?

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Re: My Fox II blew a cap!

Posted on 2018-05-13, 13:32

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

MLCC will have to be high voltage (over 25V) or very high capacitance (100µF+) if you want it to still have say 10 or 47µF of capacitance left at the specified voltage. Ceramics lose a lot of capacitance when having a DC over them. High voltage and capacitance ceramics are also expensive so you're …

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Re: My Fox II blew a cap!

Posted on 2018-05-13, 13:31

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Also: I measured all caps. Most have a resistance of 900 Ohms. Quite a few are shorted completely. Those also beep in continuous testing mode.

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Re: My Fox II blew a cap!

Posted on 2018-05-13, 13:23

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

MLCC will have to be high voltage (over 25V) or very high capacitance (100µF+) if you want it to still have say 10 or 47µF of capacitance left at the specified voltage. Ceramics lose a lot of capacitance when having a DC over them. High voltage and capacitance ceramics are also expensive so you're …

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Re: My Fox II blew a cap!

Posted on 2018-05-13, 12:53

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yeah that's how tantalum caps die after a while. Replacing them is a good idea. I have an MFM Western Digital HDD in my 8088 and some caps were making short circuit, preventing the whole computer to power up. Once I desoldered them, a third one exploded. Then I decided to replace all of them and …

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Re: My Fox II blew a cap!

Posted on 2018-05-13, 11:52

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Electronics stackexchabge has a nice writeup about tantalum capacitors: https://electronics.stackexchange.com/questio … =google_rich_qa

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Re: My Fox II blew a cap!

Posted on 2018-05-13, 10:05

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Ok. That I can measure. And shall I replace with modern Tantalum? Or rather electrolytics? Or other kinds?

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Re: Newbie to 286 systems, Ram Cards, etc.

Posted on 2018-05-13, 09:26

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

keropi wrote: or remove SIPP slots and solder SIMM slots there is also the possibility of just inserting the simm slots in the sipp pins, it will work just fine Now that is an interesting hack!

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My Fox II blew a cap!

Posted on 2018-05-13, 09:21

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have never powered it up so far, so I guess it was faulty...? It was an extremely loud bang. I can replace the 10uF tantalum, but the question is if itwas the faulty part. I can replace all the caps near the power connector if needed. Any idea how to troubleshoot this? 62F2ADDD-759A-4558-8BD0- …

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Re: How to replace removed NiCd CMOS battery?

Posted on 2018-05-13, 06:47

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There is also an Amiga blog posting about this topic: http://www.retro-commodore.eu/2014/07/23/batt … ry-replacement/ I have checked, and my Octek Fox II has the external battery connector. The other board I was talking about doesn't.

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Re: Lotech Tandy Soundboard - get it finished.

Posted on 2018-05-12, 15:53

by

by root42

in Marvin \ Sound

in Marvin \ Sound

Awesome. I love these re-engineered cards. Please do post progress!

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Re: How to replace removed NiCd CMOS battery?

Posted on 2018-05-11, 09:26

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Isn't there any external battery connector? I did not deal with any 286 boards for the last 25 years or so, but every single 386 and 486 boards with NiCad soldered batteries that I've seen had an external battery connector. I have also found this: http://amigakit.leamancomputing.com/catalog/product …

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How to replace removed NiCd CMOS battery?

Posted on 2018-05-10, 22:37

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

My 286 is missing its CMOS battery. What are my replacement options? I do not mind soldering a bit and would love some small, elegant solution. I guess I can’t put in a cr2032 just like that due to charging. Filename BA86B538-C748-416F-80AC-4D205A0BE419.jpeg File size 533.29 KiB Views 1097 views

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Re: DreamBlaster S2P : Small form factor General MIDI on parallel port

Posted on 2018-05-10, 14:52

by

by root42

in Marvin \ Sound

in Marvin \ Sound

Looks neat. However there are no schematics available, right? I like assembling my own cards. But other than that it looks very nice.

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Re: DreamBlaster S2P : Small form factor General MIDI on parallel port

Posted on 2018-05-10, 13:10

by

by root42

in Marvin \ Sound

in Marvin \ Sound

I love it. Do you think it would be possible to create an ISA version as well? 8 bit card with Keystone ISA bracket?

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Re: ATX2AT Smart Converter: Need Your Advice!

Posted on 2018-05-10, 13:06

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by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

keropi wrote: I like it. Kudos for making this xsecret - and I also like that LCD screen for some visual feedback. Is there a BOM for the needed parts? I want to build one 😀 Kicad plus BOM would indeed be nice to make our own board.

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

Posted on 2018-05-10, 08:43

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Soldered a XT CF Lite 4.1. Only the SMD CF bracket still needing soldering. Filename 88BDBFD9-E0F1-451D-A43D-41C71522E66D.jpeg File size 285.17 KiB Views 1444 views

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Re: ATX2AT Smart Converter: Need Your Advice!

Posted on 2018-05-10, 07:12

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Great project. However a 'lite' version would be nice with minimized PCB size and component count. PCB manufacturers like Aisler charge per square centimeter, so the lite version without display could be made much cheaper.

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Re: Help getting CF card running as IDE HDD replacement

Posted on 2018-04-29, 21:35

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thanks for the quick reply. I do have a bunch of 8K EEPROMS and an ISA NIC lying around. Also I have in mind assembling a XT-CF Lite 4.1 card in the future. So maybe I will first ask a friend to write the XTIDE BIOS to one of the EEPROMS and I'll put it in the NIC. Any hints on what I have to mind …

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Help getting CF card running as IDE HDD replacement

Posted on 2018-04-29, 20:31

by

by root42

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So I've already tried a lot of different things to get my 256MiB Compact Flash running in my 286 machine. I have a 256 MiB Compact Flash that identifies as 249 MiB with IDEINFO.exe, see attached screenshot. I am inclined to believe this data, because why not. You can also see the values that I …

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