Finding specs on 5150 with 5161 expansion unit

[DumbQuestionDuJour]

Hi, everyone.

I just acquired a 5150 that has a 5161 expansion unit, along with a keyboard and a (5151) monitor. It came with power cords and the cable that hooks the expansion unit to the PC and also two floppy disks, one of which is a boot disk (says Intellicon PC-MOS/386 Version 1.05/1.04, PC-DOS Version 1.05/1.04 Disk 1 of 1, (c) 1987-1989 Connect Tech Inc. (The other floppy says Intellicon, QNX Version 2.01/2.01 (and someone crossed out the numbers and wrote 2.10c)).

The various components were in their original boxes, but no documentation. The boxes don't seem to have much helpful info on them.

Much as I'd love to relive the good old days and fiddle with it for a while, unfortunately my husband lacks any sense of computer nostalgia and would like it off of the floor of his office sooner rather than later. Like "yesterday" wouldn't be soon enough for him. So I'm trying to figure out as much info as possible about it with an eye toward selling it and representing it properly.

I booted it up before hooking up the expansion unit, and it boots just fine, says "The IBM Personal Computer Basic Version C1.10, copyright IBM Corp 1981, 62940 bytes free. I assume that means it's got 64K of RAM.

I hooked it up to the expansion unit, rebooted, then turned the expansion unit on after it booted. Nothing seemed to happen. How can I tell if the expansion unit is working? And how can I tell the specs of the various things that people will want to know about it?

Any help greatly appreciated by both me and my floor-less husband.

Thanks.

 

[Chuck(G)]

Hi DQdJ,

It all depends upon what's in the expansion unit--by itself (un-populated with cards), it doesn't do anything. A photo of the rear of both units might give us a hint without having to open up either.

There's generally a fair demand for them, as the original 5150 had only 5 expansion slots and an anemic power supply, so it's a period piece for the hard-bitten IBM-er. When the 5160 came out, two things happened. First, the 5160 had 8 slots, not 5 and second, "multi" cards serving more than one purpose were plentiful. So the need for extra slots dropped off pretty rapidly.

What's puzzling is the QNX and PC-MOS/386 disks, which are intended for a much later system. I wonder if there's some sort of 80386 accelerator card in those boxes.

Hope this helps!

 

[DumbQuestionDuJour]

Thank you, Chuck(G). Here's a picture of the back of the two machines; there aren't any cards in the expansion unit besides the one that connects to the PC. There is one expansion slot cover missing, as though someone might have removed a card.

http://imageshack.us/photo/my-images/651/51505161backs.jpg/

 

[Chuck(G)]

How strange to have an expansion unit with nothing in it!

I'm trying to avoid asking you to open the unit up, as it looks to be a real bear of a job. On the front of the unit, is there anything that looks like it might be a disk drive (floppy or hard)? Sometimes these were used for nothing more than a hard disk expansion.

 

[bettablue]

Nice find! And here, I had to beg borrow and almost steal to get mine. Now that's is almost done these things (expansion units that is) are popping up all over the place.

Congratulations.

~BB~

 

[marcoguy]

I figured you'd poke your nose in this thread sometime I'm really trying to get that 5161. If it ends up on Ebay, I will probably go for it.

 

[DumbQuestionDuJour]

Looks like maybe a hard drive in the right bay of the expansion unit?

http://imageshack.us/photo/my-images/849/51505161front.jpg/

 

[marcoguy]

Yep. That's probably a Seagate ST-412 hard drive.

 

[modem7]

I hooked it up to the expansion unit, rebooted, then turned the expansion unit on after it booted. Nothing seemed to happen. How can I tell if the expansion unit is working?

Note that the 5161 needs to be powered on before the 5150 is powered on, but since there are no cards in the 5161, it won't accomplish much.

I booted it up before hooking up the expansion unit, and it boots just fine, says "The IBM Personal Computer Basic Version C1.10, copyright IBM Corp 1981, 62940 bytes free. I assume that means it's got 64K of RAM.

No, the 64K is simply how much RAM that BASIC is using. But you can determine the total amount of (conventional) RAM that there is via BASIC. Enter the following two lines in BASIC:
def seg = &h40
print peek(20)*256 + peek(19)
The figure then displayed is the total amount of (conventional) RAM in KB. There is a bug in the 5150 which means that in some circumstances the amount shown will be wrong, but if the figure shown is 256K or above, then you can be very certain about the amount shown.
Also, your 5150 may have a memory card that provides additional RAM in the form of expanded memory.

 

[DumbQuestionDuJour]

Note that the 5161 needs to be powered on before the 5150 is powered on, but since there are no cards in the 5161, it won't accomplish much.

Thank you. Somehow that's counterintuitive to me, so I appreciate the info. Do I need to leave it on for a minute or two before powering on the 5150?

I'll check out the RAM tomorrow AM when I have a bit more time.

 

[modem7]

Thank you. Somehow that's counterintuitive to me, so I appreciate the info. Do I need to leave it on for a minute or two before powering on the 5150?

You should be able to get away with powering them on at roughtly the same time, but because bettablue has a 5161, he's probably better qualified to comment.

 

[bettablue]

You should be able to get away with powering them on at roughtly the same time, but because bettablue has a 5161, he's probably better qualified to comment.

I find it i little odd that the 5150 will boot without the 5161 powered on, or attached. Everything I have read seems to indicate that the 5161 HAS to be powered on before the PC. In mie, the expansion needs to be powered on about 5 to 10 seconds before the PC That makes me also wonder if the extender card is working properly.

(Spelling corrected. Problems with eyesight.)

Please correct me if I'm wrong.

 

[modem7]

I find it i little odd that the 5150 will boot without the 5161 powered on, or attached. Everything I have read seems to indicate that the 5161 HAS to be powered on before the PC. In minw, the wxpansion needs to be powered on about 5 to 10 seconds before the PC That maked me also wonder of the extender card ir working properly.

I expect that one can power on the 5161 after the 5150, but it would have to be done within a certain time period.

I expect that the 5160 will need to be on during the 5150's Power On Self Test (POST), but at a minimum, the first element of the POST that involves the 5161.

Refer to http://www.minuszerodegrees.net/5150/misc/5150_post_and_initialisation.htm
In the web page referred to, at item 15, is a check of communications with the 5161. So the 5161 will need to be on at at least item 15. How long that is after 5150 power on is going to depend on how much conventional RAM there is (because of the varying time for item 10 to run).

In a particular situation, the 5161 will need to be on even before item 15. This will be because of item 10 (zero RAM past 64K). For example, 256KB conventional RAM on the 5150 motherboard and additional conventional RAM fitted on a card in the 5161. For the conventional RAM in the 5161 to be zeroed, the 5161 would need to be be on at the time that item 10 has finished zeroing the the first 256K of RAM (what is on the 5150 motherboard).

Please correct me if I'm wrong.

Because of item 15, I would expect that a 5150 will display an "1801" error if the 5161 is unpowered. Does your 5150 do that?

 

[Chuck(G)]

My usual stupid question: Why isn't the power on these things coupled together such that the 5150/5160 BRS turns on both units? It would seem to be pretty simple to use a M-F IEC power cord to couple them together. I suppose you could daisy-chain your monitor power from the 5161.

 

[modem7]

My usual stupid question: Why isn't the power on these things coupled together such that the 5150/5160 BRS turns on both units? It would seem to be pretty simple to use a M-F IEC power cord to couple them together. I suppose you could daisy-chain your monitor power from the 5161.

The resulting 2 seconds long power brownout usually causes one's neighbours to complain.

 

[DumbQuestionDuJour]

def seg = &h40
print peek(20)*256 + peek(19)
The figure then displayed is the total amount of (conventional) RAM in KB. There is a bug in the 5150 which means that in some circumstances the amount shown will be wrong, but if the figure shown is 256K or above, then you can be very certain about the amount shown.

512 K, apparently. That was with the expansion unit off.

It took two tries to boot this AM. It always pops up with the number 1801 when it's first turned on, then the drive spins, then normally it comes up to the "OK" prompt. This AM the disk kept spinning and the OK prompt didn't come up, just green blips quickly cycling down the screen. I turned it off, reinserted the boot disk and turned it on again and it booted normally. My mostly uneducated gut would say that maybe the boot disk is starting to show its age.

I also booted it this AM with the 5161 turned on. The hard drive light on the expansion unit came on a minute or two after I turned on the 5150, then the screen showed 1701, then the OK prompt. For kicks I did the command that Modem7 was kind enough to provide, and it still came back with 512K of ram. Probably not surprising given that there are no cards in it (assuming that additional RAM might be on a card?). Anyway, is there any way of finding out whether the hard drive is functional and/or contains any state secrets?

 

[Stone]

The 1701 error is a fixed disk drive not ready error and that's probably because the expansion unit, as previously noted, doesn't seem to have a HD controller.

The 1801 is an I/O Expansion unit POST error.

 

[modem7]

512 K, apparently. That was with the expansion unit off.

With 512K showing, the likely RAM configuration in your 5150 is 256K on the motherboard and 256K on an expansion card.

It took two tries to boot this AM. It always pops up with the number 1801 when it's first turned on,

An 1801 error basically translates to "the 5150 is having trouble communicating with the 5161". If you are seeing 1801 when the 5161 is off, but not when the 5161 is on, then I expect that.

then the drive spins, then normally it comes up to the "OK" prompt.

The boot sequence is normally:
1. If there is a boot floppy in A:, then boot from that, else
2. If there is a hard drive, then boot from that, else
3. Boot to BASIC (gives the "OK" prompt).

This AM the disk kept spinning and the OK prompt didn't come up, just green blips quickly cycling down the screen. I turned it off, reinserted the boot disk and turned it on again and it booted normally. My mostly uneducated gut would say that maybe the boot disk is starting to show its age.

Not sure what happened there. Maybe it was a hiccup.

I also booted it this AM with the 5161 turned on. The hard drive light on the expansion unit came on a minute or two after I turned on the 5150, then the screen showed 1701, then the OK prompt.

A 1701 error is produced by the ROM in an XT class hard disk controller card when the card is having problems with a hard drive. Because you only see the 1701 when the 5161 is powered on, you must have a hard drive controller card in the 5161.

A photo of the insides of both the 5150 and 5161 would be good at this time. You probably need to do that anyway to help sell the two units later.

 

[Stone]

A 1701 error is produced by the ROM in an XT class hard disk controller card when the card is having problems with a hard drive. Because you only see the 1701 when the 5161 is powered on, you must have a hard drive controller card in the 5161.

You're likely right, again, on this one. DQDJ stated there were no cards in the unit other than the extender but that was without actually opening the case. And, yes, HD controllers and slot covers look confusingly similar from the back of the case. My money's with you, again.

 

[bettablue]

Because of item 15, I would expect that a 5150 will display an "1801" error if the 5161 is unpowered. Does your 5150 do that?

Yes. Whenever my PC is booted with the 5161 turned off, the PC generates an error 1801. I wanted to verify that the expansion unit needed to be powered on, or present during the boot cycle. I tried various boot floppies and get the same error regardless if the expansion is either disconneced or powered off, however, when the extender card is removed, or the 5161 is powered on when connected, the machine/s boot as expected. No error.

So again, I have to question the extender card. Is it possible that the BIOS has been configured in such a way that it WILL boot from floppy on this particular system with the 5161 disconnected or powered off? I read somewhere in IBM's documentation that states that the eu needs to be connected AND powered on prior to booting the PC, or the PC will display error 1801. I don't recall if IBM's documentation gave a time frame though. (Sorry, I don't remember which document) And, in another post here in the forums, a user was told the same thing. He HAD to have the eu powered on for approximately 10 or more seconds before powering on the PC. The explanation was that the eu need time for any hard disks to spin up before they were accessed. In my own system, that is about right. Although, I find that 15 seconds gives a bit more time for the old drives to get up to speed and therefore boot more reliably.