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Compatibility of Xebec Controllers to IBM 5155

Chris_in_Japan

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Dear all,

I think I made a wrong buy and I was willing to ask the expert advice of yours about it.

Please check these pics:
http://s671.photobucket.com/user/Chris_in_Japan/media/up_zps01e9f737.jpg.html
http://s671.photobucket.com/user/Chris_in_Japan/media/down_zps2209bb9b.jpg.html

The controller on the right is the one I used to have in my 5155 and the one on the left is the one I may have mistakenly bought to replace it.

The questions are:
- will the left controller be able to deal with the original floppy and HDD of the 5155? Are these both compatible?
- if yes, how should those three switches be configured to allow this? (i/o address, ROM address, "option")

Many thanks and kind regards!

Chris
 

SpidersWeb

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What hard drive is in the 5155?

The card will work fine with a 5155, but it's the hard drive we'll need to know about.
 

modem7

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Of the cards you pictured, both are made by Xebec. The one on the left is the Xebec 1210. The one on the right is the 1210 modified for IBM.
From Mueller's 'Upgrading and Repairing PCs' book:

"The hard disk controller that IBM used for the XT was the Xebec Model 1210, made by Xebec Corporation. Although IBM wrote a custom ROM for the controller, Xebec shipped a compatible version of ROM when you bought the 1210 controller directly from Xebec."

Card #2

The specific card on the right is the "variation #2" one detailed at http://www.minuszerodegrees.net/ibm_xebec/ibm_xebec.htm#variation_2
Your ST-212 will work with that card.

Card #1

As for the card on the left, the 1210, the drives that it supports is determined by what is in the ROM chip. That could vary, because there were different releases of the 1210: 1210A / 1210B / 1210C
You don't have the 1210C. That is pictured at http://www.minuszerodegrees.net/ibm_xebec/ibm_xebec.htm#xebec_1210c

The 1210A and 1210B are detailed at http://museum.ttrk.ee/th99/c/U-Z/21079.htm
A variation of the 1210A is detailed at http://www.t-zero.org/archive/old_jumpers_pinouts/c/txt/21078.txt

We need to exactly identify your card in order to determine if the ST-212 is supported, and what jumper configuration is required to select the ST-212.
 

modem7

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Chris_in_Japan

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Card #1

As for the card on the left, the 1210, the drives that it supports is determined by what is in the ROM chip. That could vary, because there were different releases of the 1210: 1210A / 1210B / 1210C
You don't have the 1210C. That is pictured at http://www.minuszerodegrees.net/ibm_xebec/ibm_xebec.htm#xebec_1210c

The 1210A and 1210B are detailed at http://museum.ttrk.ee/th99/c/U-Z/21079.htm
A variation of the 1210A is detailed at http://www.t-zero.org/archive/old_jumpers_pinouts/c/txt/21078.txt

We need to exactly identify your card in order to determine if the ST-212 is supported, and what jumper configuration is required to select the ST-212.

Your answer is amazingly rich in data and allowed me to understand things much better. Thanks, Modem!!

I can tell so far now:

- Regarding "Card #1", from the dip switches/jumpers layout I think we can discard 1210A Ver.2 (the "variation" you mention). It seems I am dealing here then with an 1210A (Ver.1) or an 1210B.
- The article in www.museum... gives enough information to configure the jumpers on "Card #1" to work with a Seagate ST-212 ("ROM Addr" must be set for ST-212 listed there with --> JP2: 0,0,1,1,0,1,1 PD: 1, "I/O Add" is set because is an IBM machine --> JP1: 1,1,1,0 , "Option" is set because it is a Seagate ST-212 and for them the ROM address is C800:5 after the list in the same document --> JP3: 1,0,1,0)
- However I have to say here that I am "surprised" that www.museum shows identical settings for 1210A and 1210B. Both seem to be able to deal with an ST-212
- I am quite "troubled" to read there that "Floppy drives supported: None" since this was the reason to change my previous XEBEC controller (the one you name "Card #2". I was unable with it to fire up my FDD Qumetrak 142. My "Card #2" was operating properly the Seagate ST-212. Is the not working FDD the initial issue I had... Can be that "Card #1" is unable to control FDDs??!?
- Having set the new "Card #1" with the settings defined above, the 5155 is failing now to fire up both the FDD and the HDD.
- Certainly: I have no ultimative proof with all this that my Cards #1 and #2 are faulty since it could be the FDD. I could not google any kind of easy test for the FDD besides switching controllers as now being discussed here.
- If this is of help, I wrote down the configuration of the jumpers in the drives: The Qumetrak 142 FDD has 4 of them now set as 0,1,0,0. The Seagate ST-212 HDD has 8 of them set as: 1,0,0,0,0,0,0,0. The 5155 itself (no coprocessor installed) has his dip switch set as 0,1,0,0,1,0,1,1. Memory is checked up to 256KB...

Well... This is all what I have to report after this rainy afternoon!

Many thanks to all and have a nice WE!

Chris
 

ibmapc

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...- I am quite "troubled" to read there that "Floppy drives supported: None" since this was the reason to change my previous XEBEC controller (the one you name "Card #2". I was unable with it to fire up my FDD Qumetrak 142. My "Card #2" was operating properly the Seagate ST-212. Is the not working FDD the initial issue I had... Can be that "Card #1" is unable to control FDDs??!?
- Having set the new "Card #1" with the settings defined above, the 5155 is failing now to fire up both the FDD and the HDD....
You need a separate controller for your floppy drive. Both of those Xebec cards are built for 1 or 2 Hard drives only.

You need one of these. (Image borrowed from Minuszerodegrees.net -Sorry Ray, I didn't get permission first, hope you'll forgive me!)
5150_later_diskette_adapter.jpg


P.S.

When replying to your previous thread, I was not aware that the floppy drive was connected to the Hard Drive controller. I guess I should have read more carefully or asked for pictures of the inside of your 5155.
...The controller operates at least the hard drive since after the "F1 to resume", the PC goes and boots from the HD... Certainly I guess this does not means a non-faulty Xebec controller but before chasing a replacement "just in case" I was willing to narrow potential root causes....
I see that sentence should have tipped me off, but I just didn't see it.
 
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Chris_in_Japan

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You need a separate controller for your floppy drive. Both of those Xebec cards are built for 1 or 2 Hard drives only.

Ow! That hurts!!! No wonder I could not get my FDD running with it...

"Surprises" me that the IBM version of the Xebec 1210 (the variation #2 of www.minuszerodegrees, the one without jumpers) can control
an HDD + FDD and the "same" generic version from Xebec 1210A or 1210B (the one with all the jumpers) can't deal with a FDD!!

I see I have not choice now to go for a Xebec 1210 for IBM ("IBM 1501492") that I know from my 5160 that is able to control an ST-412 and a FDD... Anybody in the forum willing to sell me a functional one for a reasonable price and ship it to me to Europe?

Thanx!
 

SpidersWeb

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None of the 8 bit Xebecs for IBM can control floppy drives. They're hard drive controllers only.
You'll notice in the photos that none of them have an extra connector for the floppy drive.

It wasn't until the IBM AT that FDC/HDC was combined in to one card - created by Western Digital.

p.s. although the connector is the same, you need separate (and the correct) cables for the hard drive and floppy drive, just in case you were hoping to put them on the same cable - they're very different devices.

Edit: although I see ibmapc has pointed that out already :)
 
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Chris_in_Japan

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None of the 8 bit Xebecs for IBM can control floppy drives. They're hard drive controllers only.
You'll notice in the photos that none of them have an extra connector for the floppy drive.

It wasn't until the IBM AT that FDC/HDC was combined in to one card - created by Western Digital.

p.s. although the connector is the same, you need separate (and the correct) cables for the hard drive and floppy drive, just in case you were hoping to put them on the same cable - they're very different devices.

Now I'm confused... In my XT (5160) I have a Xebec with the number 1501492 on it with a cable running to the HDD and afterwards to the (full height) FDD!

Doesn't mean this that the Xebec is controlling both? If not the Xebec, who controls the FDD? The motherboard directly? And if not the Xebec, again, why the cable between the FDD, HDD and the Xebec?

Which card was originally mounted in the 5155 to control the FDD? Remember that in the 5155 there is place for only two full length cards and I have both of them busy (with a Xebec and with a second one that I ignore the purpose)!

Thanks in advance to fight my ignorance!
 

ibmapc

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...I see I have not choice now to go for a Xebec 1210 for IBM ("IBM 1501492") that I know from my 5160 that is able to control an ST-412 and a FDD... Thanx!
Are you sure about that?

I'm not aware of any Xebec cards that can handle Hard disks AND Floppy disks.
Someone please correct me if I'm wrong here.

Anyway, I think it would be easier to install a separate floppy controller since your hard disk is already working with your current controller. MFM and RLL drives usually need to be low level formatted when connected to a different type of controller. So, even if you could find a card that can handle both drives, you'll most likely lose all the data on your hard disk due to the need for LLF.

EDIT. It looks like the Xebec 1220 could handle MFM Hard disks and Floppy disk drives. But Stason.org says
Hard Drives supported
Two ST-506/412(MFM) drives
Floppy drives supported
None
But Stason has been known to be wrong before.
There are other manufacturers that made 8 bit controllers for Hard and Floppy drives, but they are getting harder to find and I still think it would be easier to install a separate board for your floppy drive.
 
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SpidersWeb

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Check your XT again. Either that floppy drive does not work, or you have a separate 34 pin cable that's actually going to a floppy controller. The only cable these devices can share is the power plug.

Cards that came about later in 16 bit form had floppy support - but they had a floppy controller chip and a separate connector for the floppy drives.

The original card that would have been in the 5155 - is the model in the picture ibmapc linked to above. I have one of those in both my IBM PC XT's and IBM PC. The HDC and FDC cards respond to different IO addresses, DMA, and IRQ - the routines are also different - as are the signals they send down the cable (and which wire they're sent down).

NB: original cards are great, but you don't have to buy the original part if you don't want to, almost any ISA (even 16bit) card with a floppy connector will run the drive - so you have options.
 
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Chris_in_Japan

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I can't be more stupid than I am because I am just an amateur... :roll:

Having got the 5155 apart several months ago to check why the FDD was not working, I serviced the FDD but since then I forgot to mount his controller card back to the motherboard!!! Aaarrrghhh!

Mistakenly thinking always that both HDD and FDD were controlled by the Xebec 1210 I only ran around the Xebec topic looking for a (not existing) failure cause.

Now with your feedbacks I realized there was something fishy here: who is controlling the FDD if not the Xebec?!? Certainly: that card stored on the shelf since several months was not helping much the poor Qumetrak. WiFi seemed to work quite weak back on those 80's.

Long story - short result: ALL parts finally assembled back and the 5155 purrs like a cat. Both HDD and FDD. I celebrated it with champagne and a PacMan + Space Invaders in nice amber monochrome sessions. What a pleasure!

Sorry guys - I am really quite ashamed! :(

Thanks to all for the help!
 

ibmapc

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Awsome, Chris_in_Japan, Glad you've got it sorted out.
I have a huge soft spot in my heart for the 5155. It was the first real computer that I owned and still play with the same one now. So, I'm always happy to help get one fixed up.

Just remember. A digital camera is a great tool when taking apart something that is not totally familiar. I always take lots of pictures when dismantling something that I couldn't put back together blind-folded.
 
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