VOGONS


First post, by starhawk

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Hi! I have a display and controller card out of a Compaq Portable III, the 286 'lunchbox' model. This was also used, identically, on the Compaq Portable 386 from what information I have available.

Mine is marked as an Assembly # 000932-001, with serial and revision numbers unmarked. A sticker at the bottom reads "M1154-001", and it is also identified elsewhere across itself variously as "SCH 000933" and "Board No. 000934-001 AW Rev E Fab Rev [E]". Two barcode stickers also are extant on its underside; one is a standard Compaq part number sticker with the number " 49054 " above the barcode; the other is wide and a sort of dark marigold yellow and reads " *9BT3E10FL* " under its barcode. A light yellow sticker immediately below the yellow barcode sticker says "REV K" in OCR-ish dot matrix printer type. There is also written "TP TPB-J.V0" in trace copper in one spot, with the text "8905" in silkscreen underneath.

Hopefully this is of some use in identifying the board until I can get a decent set of photos uploaded.

Connections to the mainboard consist of what appears to be a 50pin ribbon cable, plus a second 10pin ribbon cable reminiscent of a COMport header dongle. The only other connector present (besides a single two-pin jumper within a shielded area of the card, from which the shield's top is easily removed is an unpopulated 3pin jumper footprint just outside the shielded area.

Does anyone know how this communicates with the mainboard? I suspect that it's just ISA-8 with a nonstandard connector but I'm not sure.

Reply 1 of 8, by weedeewee

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You can always upload your photos on imgur or another hosting website and link your images here.

No idea on the connectors though.

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Reply 2 of 8, by starhawk

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Haven't had a chance to *take* em 😉

I live in an apartment with subsidized rent and I have an inspection tomorrow. It's gonna be a couple days, I need to clean and then I need to sleep...

Reply 3 of 8, by weedeewee

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From looking at the service manual and oldcrap website, I'd say you're right.
Probably a 16bit ISA slot on a 50pin IDC connector.

Right to repair is fundamental. You own it, you're allowed to fix it.
How To Ask Questions The Smart Way
Do not ask Why !
https://www.vogonswiki.com/index.php/Serial_port

Reply 4 of 8, by starhawk

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Gotta be ISA-8. Look at the number of pins.

ISA-8 = 62 pins
ISA-16 = 62 pins + 36 pins = 98 pins

50 pin IDC + 10 pin IDC = 60 pins

So either it's ISA-8 minus its two front teeth (LOL) -- I'm not sure specifically which, but T/C [Terminal Count], CLOCK [System Clock; see below], /REFRESH [DRAM Refresh Signal - Active Low; see below] /NOWS [No Wait-State - Active Low], and RESET [Duh!] seem prime candidates for sheering off here. Why "System Clock"? Because you can compensate for that with careful VRAM access timing and a couple 74xx244 or 74xx245 latches real easy like... or expensive double-port memory if that's your thing 😉 Why /REFRESH? Because VRAM, in my experience, is almost always if not always Static RAM... TBH I've never seen DRAM used in the wild, but I'm not well-traveled enough to be an authority there and I want to be clear about that. Also worth mentioning, there's a single pin each for -5vDC, +12vDC, and -12vDC -- if any two of those were deemed spurious and eliminated, that would do it quite nicely, and leave *all* the signal pins.

That said, I've not got a magic bus identifier here in my back pocket -- so I'd have a hard time working this one out on my own. Any suggestions for an easy way to tell?

Reply 5 of 8, by weedeewee

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The other 10 pin IDC looks like it is more for an external display connector, so the bus should only be on the 50 pin and considering it's specific to this machine and only for display, it won't have all of the isa signals, so you can remove all the dma lines, all but one irq line, etc...
so yeah ISA8 wil probably suit it best.

Right to repair is fundamental. You own it, you're allowed to fix it.
How To Ask Questions The Smart Way
Do not ask Why !
https://www.vogonswiki.com/index.php/Serial_port

Reply 6 of 8, by starhawk

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OK, I have an auditory logic probe, a dedicated continuity tester, and a number of multimeters. For right now I'd strongly prefer to keep this out of an actual Compaq Portable III, although I do have one such machine -- it is not operational right now, however, and it has display issues as part of that at the moment. While going into any further detail will inevitably result in a rant long enough to *gratuitously* exceed the per-post character limit, simply due to the sheer quantity of aggravation I've had off that one system, suffice to say that at this time, that's not an option I'd relish. I *do* however have a spare motherboard as well...

So... given that equipment and nothing more, what's the easiest way to work out what signals are present and what the pinout is?

Reply 7 of 8, by weedeewee

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no idea. just guessing.

easiest to test continuity on would be the ground and power lines... if you know which are which, though 5v and ground should be simple enough.
also reading the comments on the oldcrap website shows the display needing 200v, unsurprising since it's gas plasma display.

Right to repair is fundamental. You own it, you're allowed to fix it.
How To Ask Questions The Smart Way
Do not ask Why !
https://www.vogonswiki.com/index.php/Serial_port

Reply 8 of 8, by starhawk

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HV is on a separate connector 😉