VOGONS


Compudyne 486 rebuild

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First post, by cyclone3d

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I received a water damaged Compydyne 486 desktop system this last week.
The 3 main reasons I bought this system are:
Sound card - Ensoniq SoundScape S-2000
Intel 486-75 overdrive
AT desktop case

I am working on rebuilding this system. The hardest part is going to be restoring the case as you will see in the following pictures.

I'll update this first post with the parts I decide to put into the case.

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Reply 2 of 29, by cyclone3d

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External CMOS battery - I think she's dead, Jim.

battery-1.JPG

Do not expose contents to water.. HAHA, good one.

battery-2.JPG

Eternacell - not so much

battery-3.JPG
Last edited by cyclone3d on 2018-02-03, 18:30. Edited 1 time in total.

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 3 of 29, by BSA Starfire

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hope you get it sorted, looks like it'll be a lovely machine when it's done 😀

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Reply 4 of 29, by cyclone3d

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Power supply - don't think I will be re-using this.

PSU-back.JPG
PSU-bottom.JPG
PSU-side.JPG
PSU-inside.JPG

Pieces of the P8 and P9 connectors that fell off when I disconnected them from the motherboard (power supply side - the motherboard connectors are fine).

P8-P9_pieces.JPG

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 5 of 29, by cyclone3d

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Top of the 3.5" floppy drive - hrmmm - I wonder if it still works.

3.5_top.JPG

Motherboard - FX-3000 Rev 1.0 - Other than a bit of transferred corrosion from that one screw and some deposits on the keyboard connector shield, the motherboard looks pristine except for a busted capacitor - the one in between the two sockets. About the middle of the 486 CPU. Pretty sure I am going to swap this motherboard for one of the VLB motherboards I have. Such a shame to run a 486 with only ISA.

motherboard-fx-3000_rev_1.0.JPG

Looks like they were overclocking to 100Mhz - saw another motherboard for sale that also had the same exact CPU running at 100Mhz - was it a common thing back then to clock these 75Mhz OD CPUs to 100Mhz? Guessing they are the same as the DX4-100 CPUs, just sold as 75Mhz instead of 100Mhz.

33Mhz.JPG

Here is the bulk of the rust damage. This is going to be fun... 😢

below_the_PSU.JPG

PSU support removed. Soaked it with some penetrating oil to help loosen the rust between the PSU support and the metal below the support. Pretty sure I am going to have to fab up a new piece for the bottom corner and the keyboard port metal will just be gone (lower left hand corner) and maybe the metal for the optional 2x 9-pin and 25-pin ports (left of the keyboard port).

CPU_support_removed.JPG

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 6 of 29, by cyclone3d

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Bottom of the PSU-support. I think this will clean up. Going to maybe use some rustoleum after cleaning all the rusted parts in order to keep them from rusting again. Guessing I will also spray paint the rusted parts so they look better.

bottom_of_PSU_support.JPG

Removed the expansion slot bracket - had to drill out the rusted screw.

expansion_slot_bracket_assembly.JPG

Going to try and drill the screw all the way out and re-tap. If that doesn't work (guessing the plastic will melt when I try to drill), I'll use a bolt/nut to hold that side down.
The plastic has a brass insert for the screw to go into.

drilled_screw.JPG

Got the metal insert removed - see the hole I accidentally punched through on the left hand side - about mid-frame?

metal_insert_bottom.JPG

The inside of the case with the insert removed.

case_plastic.JPG

Now that everything is disassembled, I'll wait to post more until I am putting stuff back together.

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 7 of 29, by CkRtech

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Dude. So much case work and certainly lots of dedication. If you need any encouragement, you've got it.

Also! ... You could always stick with that mobo and solder in a VLB socket - be it with this project or some other one.

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Reply 8 of 29, by cyclone3d

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So after working on cleaning up the super thin metal insert, I think I am just going to cut out the bad corner and not fab up a new piece. I see no reason to actually have the whole insert as it really serves no purpose. I could even leave the whole insert out and just run a ground wire.

And instead of trying to clean up the PSU support, I could just figure out something else to use for the support.

Or I could just clean all the rusted stuff up, only cut out what has to be cut out, and then paint it black.

Blah.. not sure what I want to do.

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 11 of 29, by cyclone3d

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Upon doing a preliminary cleaning of the PSU support, I found that it is also the HDD mount. The system didn't come with the HDD, so I was unsure of where it was originally mounted.

Pretty sure it was either not mounted in the stock location or it had been removed at some point in the past because there was no indication of where it had been mounted.

PSU_Support_prelim.jpg

Going to be sticking the expansion slot bracket and the PSU support/HDD mount in vinegar to remove the rest of the rust.

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 13 of 29, by cyclone3d

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Finally got the expansion card bracket and psu support/hdd mount finished.

I soaked both for a couple days in vinegar, took them out, hand wire brushed them off, put them in for another couple days, brushed them off again as well as chipped off some of the larger rust deposits off with a screwdriver, then soaked for another day and then did the final brush and bath in water and baking soda. As soon as I dried them they flash rusted. I had to wait a couple days to paint because of the weather. These are the pics of them wire brushed right before painting.

psu-hdd-1.jpg
psu-hdd-2.jpg
exp_bracket-1.jpg
exp_bracket-2.jpg

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 14 of 29, by cyclone3d

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And here they are painted. Took a couple evenings to do this because of weather. Lame rainy season.

psu-hdd-1-painted.jpg
psu-hdd-2-painted.jpg
exp_bracket-1-painted.jpg
exp_bracket-2-painted.jpg

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 15 of 29, by cyclone3d

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I am finally getting this system put back together.

insert.jpg

I ended up having to cut out the very badly rusted portion of the metal insert. I then sprayed it with grey primer. I decided to not paint it black as I thought the grey would look good.

drive_bay.jpg

Drive bay added.

psu_support.jpg

PSU support / HDD bay added

expansion_slot.jpg

Expansion slot insert added.

motherboard_back.jpg

Bottom of the motherboard after I added some rubber laptop feet to keep it from flexing and/or shorting out with the metal insert.

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 17 of 29, by keropi

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nice save cyclone3d!
when your machine boots can you make a BIOS image and post it?
I have the same mobo hardwired for 486 but without BIOS/Oscillator - I tried a 386-version mobo bios with a 66mhz oscillator but that did not make it work - I see now why since I need a 33 or 25mhz oscillator...

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Reply 18 of 29, by amadeus777999

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Would be interesting if soldering in the missing connector would upgrade the board to a VESA Local one... the ROMTAB[1] comission would like this issue be forwarded to Congress.

Anyways - great looking machine.

[1] "Rights Of Older Machines To Access Fast Buses"

Reply 19 of 29, by cyclone3d

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keropi wrote:

nice save cyclone3d!
when your machine boots can you make a BIOS image and post it?
I have the same mobo hardwired for 486 but without BIOS/Oscillator - I tried a 386-version mobo bios with a 66mhz oscillator but that did not make it work - I see now why since I need a 33 or 25mhz oscillator...

You want the BIOS image for the motherboard that originally came in the system?

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK