486 Motherboard, Keyboard, CPU Woes

Zenith data systems / 150-0824-p2
September 24, 2010 at 18:20:13
Specs: DOS 6.22, 486SX 66MHz/ 4MB EDO
I have a few problems with my Zenith 486 mobo, and decided to consolidate them into one thread.

The most pressing issue at the time is that I'm not sure if the 486DX2-66MHz I bought off ebay is actually functional. When I boot up with it, the mobo POSTs and recognizes the , but does not go on to initialize the mouse, Intel PnP BIOS extensions, or recognize that there is no floppy drive attached.

Here is the successful boot with the SX2:
http://www.flickr.com/photos/333031...

Here is where bootup stalls with the DX2:
http://www.flickr.com/photos/333031...

I know the battery is dead, I'm waiting on an external from ebay. One last thing; the PS/2 keyboard takes a long time to be recognized. Is that normal? I'm quite new to the old 486 platform.


See More: 486 Motherboard, Keyboard, CPU Woes

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#1
September 24, 2010 at 19:30:38
Assuming the DX-2 cpu is good then there's probably a jumper setting on the motherboard that needs to be changed for a DX cpu. It may be marked on the motherboard. If not, you may be able to find it here:

http://www.resoo.org/docs/_hardware...

The keyboard is probably not a problem. Is it the original zenith KB or another? Is it an AT keyboard being used with an AT/PS/2 adapter?

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#2
September 24, 2010 at 20:38:30
Dave! In caps!

This is the same Zenith mobo as before. I uploaded a few more pictures in case they are any use to you.

http://www.flickr.com/photos/333031...

I'm using a "modern" Dell PS/2 keyboard. Total Hardware helped me identify my Dell mobo, but nothing in there looks anything like the ZDS board I have. The SX2 is supposed to be a 50MHz chip, but it shows up as 66MHz and runs. Any idea what that's about? Do you think that the jumpers could already be correct?

As far as jumpers go, I'm in the dark. The board is heavily marked, but some labels are pretty cryptic.

Immediately around the CPU are the following jumpers and labels:
J34 - Jret
J36 - J(3.3V)
J37 - Jmul
J38 - Jklk
J39 - Front Panel
J40 - Jepk
J41 - Jfane


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#3
September 24, 2010 at 23:00:23
Yeah, I'm not sure what those are. The FSB probably has a jumper to specify 25 mhz and 33 mhz. The '2' in SX-2 and DX-2 will double that for the cpu to 50 or 66. If the SX cpu is an SX-2 50 then it's being overclocked.

I came across a reference on intel's site that the zenith motherboard may be the same as the packard bell PB470. Here are the jumper settings for the PB470:

http://j12345.users1.50megs.com/men...

Note that J33 should have pins 5-6 jumpered for an SX cpu and pins 1-2, 3-4 jumpered for all others.

Examine your motherboard and see if the jumper settings on that page are consistent with it.

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Related Solutions

#4
September 24, 2010 at 23:20:00
Here's another spec site for the PB470:

http://www.uktsupport.co.uk/pb/mb/4...

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#5
September 26, 2010 at 23:46:35
The jumper labels and settings match up exactly! Even the Cirrus Logic GD5434 is the same. I switched the jumpers around for the DX2 and the boot process continued as normal. Awesome! What page indicated a link between my 486 and the PB? I suppose the Zenith could be rebranded or something. Can't be sure because I couldn't find the PB470 in total hardware.
Proud to say my first overclock was on a 486 :)

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#6
September 27, 2010 at 18:48:24
I got the possible connection on this Intel page that talked about installing their overdrive chip:

http://www.intel.com/support/proces...

Under Step 10, the second exclaimation mark talks about both your zenith and the PB470 needing the same jumper change so I thought it likely they were the same motherboard. Either they both used the same OEM board from a third party or PB got theirs from Zenith or vice versa.

I guess we're lucky they're the same cause I don't think we could have found the jumper settings for the zenith

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#7
September 27, 2010 at 21:11:19
Huh. I came across that same page but skipped that section for some reason. Good spot! ZDS was acquired in 1989 by Group Bull, then merged with Packard Bell and NEC in '96. Won't be getting any help from them.
However, the identity mystery of the board is solved. The 150-0824-P2 is the motherboard of a Z-Station 510 desktop computer from 1994. I found this old-timey article which puts the price of the computer at $2,969! I paid a bank-breaking $1 for the board...

http://books.google.com/books?id=Ez...


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#8
September 27, 2010 at 23:38:29
I found someone selling that motherboard on ebay. They said it was P-II, no doubt because of the P2 in the model number.

$1.00 is a pretty good deal. The cpu by itself is worth $4 - $5 for gold scrap. But some of those older motherboards are selling pretty good on ebay.

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#9
October 10, 2010 at 19:16:36
Unfortunately, my deal excluded the riser board. It was a simple 3 ISA slot expansion card, but I doubt I could find that specific one for a decent price. Are some riser boards created equal? Do you think another would work just as well?

I'd like to say thanks for all your time and effort across my multiple posts. You're a great help. Thank you!


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#10
October 10, 2010 at 21:49:16
You're welcome. I've seen older type riser cards that look to be EISA and some look like 8 or 16 bit ISA.but I don't know if they're universal. My guess is if you find one from a 486 packard bell and it fits then it'll probably work. I doubt there would be any reason for the manufacturer to change the riser cards for basically the same motherboard

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#11
October 26, 2010 at 10:28:33
I found a Dell ISA riser board with 3 slots. How would I go about testing it?

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#12
October 26, 2010 at 13:22:20
I guess you'd have to first see if it fits and the contacts in the slot match those on the board. I'm not sure if the slot is going to be ISA or EISA but you can't use an ISA card in an EISA slot and vice versa.

If the slot matches and the riser fits OK I guess you start it up with no card in the riser and see what happens. If it boots OK I guess you could try a card in it and boot up again.

Seems kinda risky though. Even if it fits there's no guarantee the pin configuration is the same.

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#13
November 1, 2010 at 15:39:30
The board booted right up with the riser card in. The pins matched exactly. I rebooted, installed CTMC and the driver for my Sound Blaster 16 WavEffects, CT4170. Minutes later I had sound and MIDI playing Mechwarrior 2. Success!

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#14
November 1, 2010 at 22:34:37
That's good. I'm glad it worked out.

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