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Help ID a Mystery Card

tempest

tempest

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Sep 16, 2014
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My IBM 5150 came with two cards in it, one it a disk controller card, but the other one is a rather strange card. It say:

MULTITECH F06 1110 5.01 on the lower right
MFB-PC PB8405510-2A on the lower left.

It has two cables coming off of it which according to the card are for PRINTER and COM2. The card also has two sets of dipswitches for configuring it. I'd guess this is some sort of memory card plus printer card, but I can't find any info on it online. Anybody know what this is? Here's a pic:

mysterycard.jpg
 
From the looks of it, it's a RAM+2 serial+clock+parallel board.

TH99 might give a clue to the switch settings, but my guess is the one closest to the DRAM array controls the base address. The other switch block probably controls the various peripherals.
 
So it's like a SixPackPlus kind of deal? That would be helpful in expanding this machine to 640K.
 
tempest said:
So it's like a SixPackPlus kind of deal? That would be helpful in expanding this machine to 640K.
Click to expand...

Yep. Might want to replace that battery before it leaks.
What RAM chips are in it? If you've got two rows of 256 chips and one row of 64's - it'll make a 256KB machine in to 640KB on it's own.
 
Yeah I noticed that. What kind of battery is that?

I'm not sure on the chips, I'll have to check tomorrow. I also don't know what revision my motherboard is, how can I tell? I think it said 64K-256K on it though.

I need to get a video card for this beast and see if it even works. I'm looking for a nice Hercules card to use with my 5151.
 
256KB would have been my guess. Chips would be 4164 type. There were a bucketload of these things and the TH99 list is very incomplete. Mutlitech should not be confused with Multi-Tech who mostly made modems. I think Multitech changed their name at some time--I have a manual for a Multitech XT clone system.
 
SpidersWeb said:
What RAM chips are in it? If you've got two rows of 256 chips and one row of 64's - it'll make a 256KB machine in to 640KB on it's own.
Click to expand...
Two rows of 256K plus one row of 64K = 576K

Two rows of 256K plus two rows of 64K = 640K

But, a motherboard with zero RAM on it won't boot. :)
 
Ok I got the chip numbers off the card:

2 rows of KM4164B-12 (64K)
1 row of TMS 4256-15NL (256K)

The motherboard has all the banks populated as well:

Bank 0: soldered in. I assume 64K
Bank 1: MB8264-20 (64K)
Bank 2: MOSTEK 8406 (64K)
Bank 3: MB8264-20 (64K)

So that would mean my motherboard has 256K (nice) and that memory card has 384K which means my system should have a full 640K.
 
Anyone know the specs on that battery so I can replace it? I'm going to assume it's no longer any good.
 
Looks like a plain old 3V NiCD unit (i.e. it's a rechargeable), but I'm guessing. You're going to need a closeup of the battery before anyone can say for certain.
 
Anyone have info on the dip switch settings for this card? I think it's interfering with my XT-IDE card.
 
tempest said:
Anyone have info on the dip switch settings for this card? I think it's interfering with my XT-IDE card.
Click to expand...
To prove/disprove the interference hypothesis, how about temporarily removing the card.
Your conventional RAM will fall to 256K (what is on the motherboard), but that is enough RAM to test the hypothesis.
 
Chuck(G) said:
256KB would have been my guess. Chips would be 4164 type. There were a bucketload of these things and the TH99 list is very incomplete. Mutlitech should not be confused with Multi-Tech who mostly made modems. I think Multitech changed their name at some time--I have a manual for a Multitech XT clone system.
Click to expand...

Multitech later changed their name to Acer. I own a Multitech MPF-1B "Micro-Professor" Z-80 trainer, and it's a rather interesting machine. Apparently, they're still being produced today, though not by Acer, of course.
-Adam
 
modem7 said:
To prove/disprove the interference hypothesis, how about temporarily removing the card.
Your conventional RAM will fall to 256K (what is on the motherboard), but that is enough RAM to test the hypothesis.
Click to expand...

I tried that, apparently it's not the issue after all. I'd still like to know what the settings are though.
 
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