Help with mystery Wang 486SX desktop \ VOGONS

Help with mystery Wang 486SX desktop

Topic actions

First post, by websterp

Posted on 2023-09-01, 03:52

websterp Offline

Rank Newbie

Rank: Newbie
Posts: 7
Joined: 2023-09-01, 02:33

Guys, I need your help identifying and troubleshooting a Wang Labs 486SX 25Mhz desktop I recently picked up.

The model or series mentioned on the front panel is LP451 but I'm unable find a single reference on the internet or a discussion thread related to this except for a FCC record.
It looks like the same case design was shared with another model "Wang Alliance 750CD" and there was a single blog post where I could see a photo of the mainboard but unfortunately it was for a 386SX board which is quite different to what I have.

The problem I'm having is it would not POST. No display, no beeps or codes on the ISA Diag card. The board is extremely clean and not a spec of dust inside the case so I 'd assume it was sitting in a rack or a datacenter of some sorts. I've done the usual checks, voltages are OK, BIOS OK, crystal beats at 50MHz however due to lack of any available information I'm unable to proceed any further. When I got it none of the L2 cache sockets were populated so I'm not sure if someone scavenged the chips or this is how it had been and again I'm unable to verify even if the cache jumpers are set correctly (they all seem to be in the off position however).

I would like to populate the LIF socket with another 486SX that I know works but I don't really want to mess around with the jumpers and fry something in case I set the wrong voltage. I even spent couple of hours searching retroweb and other vintage mainboard databases thinking the same board could have been used by another OEM, etc. but to no luck.

Would one of you have the same model or something similar so I could ask for a photo of how the jumpers are set? If not I'd appreciate some help and guidance on how to troubleshoot this board and to check if the jumpers are set correctly and/or disable the onboard 486SX and set voltages for a socketed CPU.

Thank you.

P.S. : The CR3032 mod is something I've added.

Reply 1 of 16, by Disruptor

Posted on 2023-09-01, 04:12

Disruptor Offline

Rank Oldbie

Rank: Oldbie
Posts: 1488
Joined: 2018-03-22, 18:31
Location: European Union

Ah, unpopulated 9 cache sockets + dirty tag ram socket.

But why do you want to install another 486 SX?
I don't consider this board to support multi processors.

I'd try to check the failing boot process with a Port 80 diagnostics card.
Which RAM modules have you tried?

Reply 2 of 16, by wierd_w

Posted on 2023-09-01, 04:50

wierd_w Offline

Rank Member

Rank: Member
Posts: 473
Joined: 2023-07-14, 06:20

Fairly confident the lif socket disables the smt onboard qfd when populated in an either-or way.

Eg, if you have a snazzy overdrive to pop in there or something.

Reply 3 of 16, by websterp

Posted on 2023-09-01, 05:16

websterp Offline

Rank Newbie

Rank: Newbie
Posts: 7
Joined: 2023-09-01, 02:33

wierd_w wrote on 2023-09-01, 04:50:

Fairly confident the lif socket disables the smt onboard qfd when populated in an either-or way.

Eg, if you have a snazzy overdrive to pop in there or something.

I have a 486DX2 to test and the purpose of this was to eliminate a faulty onboard CPU (unlikely I know)
That is why I'm struggling without knowing how and what jumpers are to be set for CPU speed /SX/DX change. TBH I don't even know if the jumpers are set correctly for the existing CPU and that is one thing I'd like to verify.
I got a feeling this D/S jumper has something to do with choosing the active CPU swap or does it change DX/SX ?

Reply 4 of 16, by websterp

Posted on 2023-09-01, 05:21

websterp Offline

Rank Newbie

Rank: Newbie
Posts: 7
Joined: 2023-09-01, 02:33

Disruptor wrote on 2023-09-01, 04:12:
Ah, unpopulated 9 cache sockets + dirty tag ram socket. […]
Show full quote

Ah, unpopulated 9 cache sockets + dirty tag ram socket.

But why do you want to install another 486 SX?
I don't consider this board to support multi processors.

I'd try to check the failing boot process with a Port 80 diagnostics card.
Which RAM modules have you tried?

I don't necessarily want to install another CPU, just one step in the process of elimination. So not trying to run muti processors only want to change the active CPU to the socketed one.
Have tested with 4 x 1MB SIMMs and diag card always show 00-00 and no other code chnages.

Reply 5 of 16, by wierd_w

Posted on 2023-09-01, 05:25

wierd_w Offline

Rank Member

Rank: Member
Posts: 473
Joined: 2023-07-14, 06:20

that board clearly uses an isa riser board.

Have you tried starting with the riser removed, and onboard vga?

Reply 6 of 16, by websterp

Posted on 2023-09-01, 05:38

websterp Offline

Rank Newbie

Rank: Newbie
Posts: 7
Joined: 2023-09-01, 02:33

wierd_w wrote on 2023-09-01, 05:25:

that board clearly uses an isa riser board.

Have you tried starting with the riser removed, and onboard vga?

Tried that too but unfortunately no beeps or anything on the screen.

Reply 7 of 16, by wierd_w

Posted on 2023-09-01, 05:55

wierd_w Offline

Rank Member

Rank: Member
Posts: 473
Joined: 2023-07-14, 06:20

What is the fccid? I might be able to find something

Reply 8 of 16, by websterp

Posted on 2023-09-01, 06:09

websterp Offline

Rank Newbie

Rank: Newbie
Posts: 7
Joined: 2023-09-01, 02:33

wierd_w wrote on 2023-09-01, 05:55:

What is the fccid? I might be able to find something

If you are able to, that would be amazing

https://fcc.report/FCC-ID/B4YLP451-33C
https://fccid.io/B4YLP451-33C

This is for a 33Mhz 486 and mine is 25Mhz but the model is the same.

Reply 9 of 16, by wierd_w

Posted on 2023-09-01, 06:56

wierd_w Offline

Rank Member

Rank: Member
Posts: 473
Joined: 2023-07-14, 06:20

You said the bios is OK, does this mean you dumped it?

If so, can I see a copy of the dump? The ID strings inside may point to a board oem. (Wang used outside oems like tulip and pals)

Reply 10 of 16, by websterp

Posted on 2023-09-01, 07:35

websterp Offline

Rank Newbie

Rank: Newbie
Posts: 7
Joined: 2023-09-01, 02:33

wierd_w wrote on 2023-09-01, 06:56:

You said the bios is OK, does this mean you dumped it?

If so, can I see a copy of the dump? The ID strings inside may point to a board oem. (Wang used outside oems like tulip and pals)

BIOS dump here: https://tinyurl.com/4w7k89a3

The strangest thing is I cannot find any information about this model at all. I know Wang mostly focused on large corporates and businesses but surely they sold few of these worldwide and some survived and end up with individuals and collectors?

If it helps I tracked down the exact FCC ID for this model. https://fcc.report/FCC-ID/HZ4LP451
It gets even more bizarre, the applicant is President Technology Inc not Wang Labs.

Reply 11 of 16, by wierd_w

Posted on 2023-09-01, 07:56

wierd_w Offline

Rank Member

Rank: Member
Posts: 473
Joined: 2023-07-14, 06:20

The Identity string for this bios is:

40-0001-ZZ1491-00111111-070791-OPTIWB

The lookup code for manufacturer ID 1491 is President Technologies. We should try looking there.

Reply 12 of 16, by PC Hoarder Patrol

Posted on 2023-09-01, 08:15

PC Hoarder Patrol Offline

Rank l33t

Rank: l33t
Posts: 2105
Joined: 2018-03-04, 19:59

wierd_w wrote on 2023-09-01, 07:56:
The Identity string for this bios is: […]
Show full quote

The Identity string for this bios is:

40-0001-ZZ1491-00111111-070791-OPTIWB

and declares copyright 1990.

The lookup code for manufacturer ID 1491 is President Technologies. We should try looking there.

Might not be much help as that's what Wang Labs changed their name to (look at the FCC ID on the Wang Alliance 750CD)

Reply 13 of 16, by wierd_w

Posted on 2023-09-01, 08:56

wierd_w Offline

Rank Member

Rank: Member
Posts: 473
Joined: 2023-07-14, 06:20

I have come up empty.

At this point, I would just start doing original research:

Record the current positions of all jumpers and DIP switches.

Begin systematic process of binary progression through each configuration, and documenting effects. Methodical, boring, unpleasant, but only option available at this point.

Reply 14 of 16, by Disruptor

Posted on 2023-09-01, 10:24

Disruptor Offline

Rank Oldbie

Rank: Oldbie
Posts: 1488
Joined: 2018-03-22, 18:31
Location: European Union

websterp wrote on 2023-09-01, 05:21:

I don't necessarily want to install another CPU, just one step in the process of elimination.

Basically you need a 487 SX or a 486 ODP (not the ODPR) to test this. But I guess you don't have access to one.

Reply 15 of 16, by rasz_pl

Posted on 2023-09-01, 15:38

rasz_pl Offline

Rank l33t

Rank: l33t
Posts: 3581
Joined: 2017-06-04, 00:57

Disruptor wrote on 2023-09-01, 10:24:

websterp wrote on 2023-09-01, 05:21:

I don't necessarily want to install another CPU, just one step in the process of elimination.

Basically you need a 487 SX or a 486 ODP (not the ODPR) to test this. But I guess you don't have access to one.

or modding the socket for ordinary 486?

Open Source AT&T Globalyst/NCR/FIC 486-GAC-2 proprietary Cache Module reproduction

Reply 16 of 16, by websterp

Posted on 2023-09-01, 23:09

websterp Offline

Rank Newbie

Rank: Newbie
Posts: 7
Joined: 2023-09-01, 02:33

rasz_pl wrote on 2023-09-01, 15:38:

Disruptor wrote on 2023-09-01, 10:24:

websterp wrote on 2023-09-01, 05:21:

I don't necessarily want to install another CPU, just one step in the process of elimination.

Basically you need a 487 SX or a 486 ODP (not the ODPR) to test this. But I guess you don't have access to one.

or modding the socket for ordinary 486?

I already have the following which are all 5v CPUs so should fit in the LIF without needing any voltage modifications
Cyrix CX486 DX2 66
i486DX 33
i486DX2 66

But as you said these won't disable the onboard i486 as none of these have the 169pin socket 1 pinout unless there is some sort of jumper trickery you can perform on the mainboard which will disable it. Without any available manuals or guides for this model it looks like the only way to move forward would be to test all jumper combinations similar to advice from wierd_w

Go to top of page Go to top of page

Back to General Old Hardware