Xebec in 5150 issues

[bobba84]

Hi guys,

I'm after some advice - I have an ST-412 in my 5150 using some cheap aftermarket 'Longshine' MFM card - which works fine, but I'm after originality!

So, I bought a Xebec MFM card for it (variation 1 shown here)
Obviously the drive won't boot, as the low level format is different. It tries to, ie. the hdd light flashes a few times before it carks it to BASIC.
No problem, I thought, I'll load up debug and do a low level format.
Consistently, the first time I try, it says 'divide overflow' and jumps back to DOS. Consistently, the second time I try, it freezes.

Any ideas guys? I was thinking bad BIOS? Although the HDD light flashing when it attempts to boot makes me think it's at least partially okay.

Somewhere I have another card the same with heaps of pins bent off (was like that when I found it in a discount bin at the local electronics store) - I could pull the BIOS from there and try... I'm assuming the BIOS is the only socketed chip? Up the top to the right of the big beefy transistor?

What do you think? Any other possibilities?

Thanks in advance for any help

Bobby.

 

[modem7]

I have an ST-412 in my 5150 using some cheap aftermarket 'Longshine' MFM card - which works fine, but I'm after originality!

But IBM never put a hard drive inside the 5150 !

No problem, I thought, I'll load up debug and do a low level format.
Consistently, the first time I try, it says 'divide overflow' and jumps back to DOS. Consistently, the second time I try, it freezes.

I located my spare ST-412 and spare 'variation #1' IBM/Xebec controller, and placed them in an IBM 5150 (64-256K motherboard with 640K RAM total).
I powered the ST-412 from a second power supply, not being prepared to 'stress' my 5150's 63W power supply.
The 'Step 1' portion of the DEBUG process at [here] executed as expected; the ST-412's light came on solid, and I could see the drive's stepper arm slowly moving.

Somewhere I have another card the same with heaps of pins bent off (was like that when I found it in a discount bin at the local electronics store) - I could pull the BIOS from there and try... I'm assuming the BIOS is the only socketed chip? Up the top to the right of the big beefy transistor?

My 'variation #1' has two socketed ROMs. Of those, the BIOS one is the one in the bottom-right corner (marked 5000059). Of course, either ROM could be faulty.

What do you think? Any other possibilities?

Sounds like a bad controller to me.
Did you try cleaning the controller's edge connectors, and try reseating the socketed ROM?

 

[Stone]

Try it again with the Longshine card, just to prove that the drive hasn't croaked in the interim.

 

[modem7]

Before putting my kit away, I verified a behaviour that I expected. I disconnected the drive and cables from the controller. Then, I observed that whenever I powered up the 5150, displayed was a "1701" error code (after a time-out period). The 1701 is generated by code in the controller's BIOS ROM.

[ That would not have occurred had my 5150 motherboard been fitted with the first or second revision of BIOS. I know that your 5150 motherboard does not have either of those revisions, because your Longshine controller is operational in your 5150. ]

BTW. PM me if you are interested in acquiring a functional IBM/Xebec controller from me.

 

[bobba84]

But IBM never put a hard drive inside the 5150 !

I know but at least the xebec card and ST-412 were IBM provided.

The 'Step 1' portion of the DEBUG process

Argh! I forgot about the Xebec card needing all that. I was using g=c800:5 - I'm going to go back and try it again! Thanks

Thanks for taking the time to run that test for me. I'll come back with an update later.

Also Stone, thanks.. good thinking. If I have no luck with the proper procedure I'll do just that.

 

[bobba84]

The problem is resolved! Consider this a PEBKAC error... I forgot that the Xebec didn't like the usual g=c800:5 in debug to start the low level format.



Thanks modem7 for reminding me, and Stone for the suggestion of trying the old card... I did that first to ensure the drive was okay.

My 5150 now has a working ST412 with no bad sectors!


Thanks again!
Bobby.