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Jimmy
February 2nd, 2016, 04:23 PM
I have what I believe is a receiver card for an IBM 5161 expansion unit. It is slightly different from the receiver card in my working 5161. I got another 5161 recently, well kind of, it had a working transmitter card, the chassis is for an IBM 5160 rather than a 5161. The power supply I think is also from a 5160 and this card pictured below. The unit does work with either transmitter cards and the card from the other unit.

I am posting some pictures here, first to make sure it is a receiver card and second if it is, has anyone ever repaired one of the cards?

When this receiver card is installed in the unit, I get a post error of 1801.


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rittwage
February 2nd, 2016, 05:21 PM
5161 receiver card is PN 1501426

Yours is 1503902 which the FRU lists as "IBM - BUS RED C"

I've no idea what that card is for, but it's not a 5161 reciever card. Sorry. :)

Jimmy
February 2nd, 2016, 05:33 PM
I knew it was different from my working card, but not a lot I will post pictures of my working card for comparison. I have an IBM 5364 "Baby 36", I will take a look at the card in it. The same cable works on both.

modem7
February 2nd, 2016, 09:58 PM
I am posting some pictures here, first to make sure it is a receiver card
Your card looks just like the known receiver card at http://www.minuszerodegrees.net/5161/misc/5161_receiver_card%20%28eBay%29.jpg


When this receiver card is installed in the unit, I get a post error of 1801.
1801 is known to occur when a receiver card is plugged in, but the POST's (power on self test) attempt to communicate with the 5161 unit fails.
Some causes:
* 5161 is not attached to receiver card
* 5161 not powered on
* Computer powered on, and then some time later, 5161 powered on (ideally, 5161 should be first powered)


5161 receiver card is PN 1501426
Yours is 1503902 which the FRU lists as "IBM - BUS RED C"
I've no idea what that card is for, but it's not a 5161 reciever card. Sorry. :)
One has to be careful about the IBM part numbers printed on things.
There is a difference between an actual part number and a FRU (field replaceable unit) part number.

Jimmy
February 3rd, 2016, 04:54 AM
That is the card exactly, as I stated earlier it is slightly different from my working card.

I can plug the other receiver and the PC starts fine and can access the hard drive in the expansion unit.

I start the 5161 and 3 to 5 minutes later, I power on the PC. Since the 5161 works correctly with the same setup and the other receiver card, I logically looked to the card I posted as the problem.

I have not tried it the other way, putting this receiver card in the other working 5161 unit, but I will.

I will also post images of both sets of cards.

Thank you for the help.

Jimmy
February 3rd, 2016, 07:40 AM
Here are pics of the working receiver card.

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Are the chips on these cards common and still available?

Can I piggy back these chips to test if the are available, or is this a lost cause.

Any advice would be greatly appreciated.

Thank you,

Jimmy

modem7
February 3rd, 2016, 11:33 PM
1801 is known to occur when a receiver card is plugged in, but the POST's (power on self test) attempt to communicate with the 5161 unit fails.
Doh. My "receiver card" should have been "extender card".


Here are pics of the working receiver card.
That is quite different to your working card.
So, an anomaly.
Is rittwage right (and people are passing off xxx cards as receiver cards), or did IBM produce more than one version of the receiver card.
Is there anyone with a working 5161 whose receiver card matches the one shown in post #1 ?

Jimmy
February 4th, 2016, 04:20 AM
I know Thomas BettaBlue here in the forum has an 5161 working I will PM him and ask him to compare the pics of the two cards I posted to his.

lyonadmiral
February 4th, 2016, 04:42 AM
I know Thomas BettaBlue here in the forum has an 5161 working I will PM him and ask him to compare the pics of the two cards I posted to his.

I also have a working 5161 as well if Tom can't get you a picture.

Jimmy
February 4th, 2016, 10:03 AM
Here are the pictures of the 3 receiver cards that I have.

The card to the left is the receiver card from the 5364 System/36.

The middle card works with both transmitter cards and both 5161 expansion cabinets.

The card in the right matches Zero Degrees website but does not work. I am not sure if I have a broken card or simply the wrong one.

I can find all the chips on the board but do not know if it is defective or simply the wrong card.

If you can compare the pictures to yours and let me know which one matches, I would greatly appreciate.

Jimmy




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Jimmy
February 5th, 2016, 04:41 AM
Okay, I checked with Thomas (BettaBlue) here on the forum and Dan (LyonAdmiral) and both their receiver cards match the middle card in my earlier post, which is the same card that works with my transmitter card.

Ray, I am not sure what the card I have is. I tried to research IBM PN 1501426. I got several google hits for a receiver card for an IBM 5364 Baby 36, which it does not match either, the first card on the left is that card.

The pn 1503603 as stated in the previous post in this thread lists as a BUS RED C, whatever that is.

modem7
February 6th, 2016, 01:33 AM
For some cards, IBM have produce variations. So we have to be careful not to use the flawed logic of, 'Card XXX does not look the same card YYY, therefore, card XXX and card YYY are not interchangeable.'

No one has responded in the affirmative to my question at post #7. So, we are none the wiser. The subject card of yours could be either:
1. Not a 5161 receiver card at all (even though in the past advertised as a receiver card).
2. One of multiple versions of the 5161 receiver card, and yours is faulty.

But so far, the evidence leans towards it not being a 5161 receiver card.
If someone else obtains the same card, and that too is found not to function (as a 5161 receiver card), then that would make the case stronger.

One way to resolve the matter once and for all would be to work out the card's circuit diagram.

For me, I normally don't use eBay photos unless I know what the photo subject is, or have adequate confidence of such. I can only guess that someone on these forums pointed to the card on eBay as being a 5161 receiver card, and no one challenged it.

snuci
February 6th, 2016, 05:58 AM
I checked my receiver card and it is the middle card (1501426). It has a mid 1983 date code. Your 1503902 card has components fro 1986 or 1988 (hard to read).

In the description found for this card, it says "BUS RED C". Could that be "BUS REDirector C" or maybe "BUS REV C"?

Maybe two of these cards are required to communicate bus signals as opposed to a traditional Rev A extender/receiver card combo? It's total speculation but I don't think it matches either an extender or receiver card.

Good luck on your search.

Jimmy
February 6th, 2016, 04:08 PM
Ray:

I agree all I know for sure is the card does not work with either of my Transmitter Cards. I did look up all the chips on the card and they are available. When I first posted the thread I was thinking I might give it a shot at repairing it.

I am going to put it on the back burner and dig into the IBM 5364 Baby 36.

As always thanks for the expect help and advice.

snuci
February 29th, 2016, 07:40 AM
I think I might have an answer to this but I have not tried them yet. I recently acquired a card set from a person who has sold several expansion units. He has an extra set of cards that appear to be the later version ones matching one of the cards that Jimmy has found in his expansion unit. In my set, the Receiver card is IBM part number 1503902 and the Extender card is part number 1503905.

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Please see this post I just made for more pics. (I hope I didn't mix up the Extender/receiver part numbers).

http://vintagecomputer.ca/ibm-5161-expansion-unit/

I will give these a shot but I have been a little hesitant that I may screw up my expansion unit.

Hope this helps.

lyonadmiral
February 29th, 2016, 08:22 AM
I think I might have an answer to this but I have not tried them yet. I recently acquired a card set from a person who has sold several expansion units. He has an extra set of cards that appear to be the later version ones matching one of the cards that Jimmy has found in his expansion unit. In my set, the Receiver card is IBM part number 1503902 and the Extender card is part number 1503905.

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Please see this post I just made for more pics. (I hope I didn't mix up the Extender/receiver part numbers).

http://vintagecomputer.ca/ibm-5161-expansion-unit/

I will give these a shot but I have been a little hesitant that I may screw up my expansion unit.

Hope this helps.

I'm not sure that the picture of ...905 is an extender card. Extender cards are usually longer and they have dip switches so you can tell the expansion unit how much memory is in the system unit so that memory expansion cards in the expansion units can be addressed correctly.

snuci
February 29th, 2016, 11:19 AM
I'm not sure that the picture of ...905 is an extender card. Extender cards are usually longer and they have dip switches so you can tell the expansion unit how much memory is in the system unit so that memory expansion cards in the expansion units can be addressed correctly.

I was thinking about this too but because these re a later revision, perhaps they don't need the jumpers to determine memory size or add wait states any longer? Just a thought.

modem7
February 29th, 2016, 03:23 PM
Per [here (http://www.minuszerodegrees.net/5161/misc/5161_extender_card_switches.htm)], the switches on the known 5161 extender card control the address range in which the extender card signals the CPU to generate a wait state.
So, the switches are set per what memory (RAM + ROM) resides in the 5161, so that a wait state occurs when that memory is accessed.

To me, it seems unlikely that IBM suddenly decided that such wait states were no longer required. Surely that is-it-required-or-not analysis was done at 5161 design time.

modem7
February 29th, 2016, 04:42 PM
.
There appears to be some contradiction in the IBM documentation:

RAM cards are not allowed in 5161 ?

* The IBM 5161 Product Announcement document includes, "Options: Memory cards, the Diskette Adapter, and the system monitor/display attachment card must reside in the system unit. Other IBM attachment adapters may reside in either an expansion unit or system unit."

* Within the IBM Options and Adapters manual, the 'System to Adapter Compatibility Chart' indicates that IBM's RAM cards are not supported in the 5161.

RAM cards are allowed in 5161 ?

* The 'IBM Expansion Unit' section of the IBM Options and Adapters manual, contains, "The DIP-switch settings determine which address segments have a wait state inserted during memory-read and memory-write operations. Wait states are required for any memory, including ROM on option adapters, in the expansion unit."

A possibility

When I think about it, a RAM card in the 5161 is a bad idea - it will incur a wait state, affecting performance. Best that it go into the 5160. If the subject card is a newer version of the 5161 extender card, maybe IBM's thoughts were something like:
"We have indicated that RAM cards and video cards are not allowed in the 5161. Therefore, we only need to worry about addresses C8000 and above (the Xebec-made-for-IBM hard disk controller has a ROM at C8000). The new extender card will be hard-wired to have a wait state generated for the address range of C8000 to EFFFF."

Not nice, but a possibility.

I wonder what the third-party extender cards do.

Jimmy
March 2nd, 2016, 04:05 AM
Dan:

Please let me know if you test the cards and they work. Since I have a spare 5161 planer board and the matching receiver card to the set you have.

Thanks,

Jimmy

snuci
March 2nd, 2016, 08:56 AM
@modem7

Perhaps these are two different revisions of the manuals because there were two revisions of the 5161 expansion unit so, technically, both are correct but the version that says "no ram cards" is newer? It's pure speculation but I can't think of any other reason to have different revisions of extender/receiver cards if that's, in fact, what I have. @Jimmy found his on the 5161 planar board but it was in a 5160 case. I can't make sense of this unless the planar and cards were sold as kit and you needed to provide your own case and power supply.


@Jimmy if your planar board is identical to mine, I'll give it a shot. If it's a different revision than maybe my cards need to go with that revision instead of the one I have. Can you provide pics of identification markings on your planar?

snuci
March 2nd, 2016, 03:17 PM
So I took a chance and tried it out tonight. No luck. I put everything back and tried my expansion unit again and it was fine; no damage done. Sorry I didn't have better news. Now we have a second mystery card :)

Jimmy
March 7th, 2016, 06:33 AM
Sorry for the delay is posting the Planer board from the 5161, been under the weather for a few days.

Thanks,

Jimmy


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