Apple UDC problem (Universal Disk Controller)

4 replies [Last post]
transwarp II guy's picture
Joined: Mar 7 2013
Posts: 466

I just recently got a hold of a UDC card, and I'm just now getting around to testing it.

I have only been able to test it with a standard Apple 5.25 drive. Instead of regularly booting like it should, It makes a loud revving noise and then comes up with the following message:

"Error Number: 40

Boot error. Please check your
diskette and disk drive."

So far I have checked very minor things and have come up with no clues.

Any ideas?

Pictures coming soon...

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Joined: Dec 19 2003
Posts: 833
Re: Apple UDC problem (Universal Disk Controller)

Start with the usual maintenance for the drive; clean the heads and calibrate the speed. The discussion on how to do both of those is findable with a search here on the 'Fritter.

transwarp II guy's picture
Joined: Mar 7 2013
Posts: 466
Re: Apple UDC problem (Universal Disk Controller)

Update: I just got an Apple 3.5 drive in the mail today. I threw everything I could at the UDC and it works GREAT! However still the 5.25 drive does not work..... Even daisy chained through the 3.5 drive... Things that make you go hmmm.

This is an excellent 5.25 drive. Cleaned, kept up with, drive speed is at 299, etc. I'm not sure what is up with it. It still does the same load spin up and shows the same boot error code.

Here you can see someone with a similar problem:!topic/comp.sys.apple2/9obXOzozDZw

They suggest that's it's normal. It seems like if the factory manual say's it can support apple 5.25 drives then it should work just fine.

It's not too big of a deal though. The 3.5 drive's performance is great to say the least. Also, the preferred slot is #5 so I've just decided to keep my 5.25 card/drive in slot #6. So I can still access both my 5.25 drive and my 3.5 drive. The UDC is a very noticeable upgrade compared to the Liron / Unidisk 3.5 I was using. The standard Apple 3.5 drives are noticeably faster.

Still, if anyone has some advice please let me know.

Joined: Dec 20 2003
Posts: 361
Re: Apple UDC problem (Universal Disk Controller)

There's a couple of different EPROMs for the UDC out there. If you have an EPROM burner, I'd try a different EPROM and see if that makes a difference.

Joined: May 27 2013
Posts: 795
Re: Apple UDC problem (Universal Disk Controller)

I have a UDC and got the same error code when trying to load MECC.

I believe that the problem lies in the Prodos file or Prodos format.

The card will not load for me Copy II Plus 9.1 (on 5.25 drive a9m0107) but there is a fix for it.

Here is how:

After formatting a disk for Prodos, take from a copy of System Utilities 3.1 the Prodos file and the Basic.System file (Prodos 8 Version 2.0.3) and copy them onto the new disk. Copy the rest of the files from the Copy II Plus 9.1 disk onto the new disk, Sort the catalog to match the original disk and then change the volume name to match.

Copy II Plus 9.1 and Laser UDC loading problem fixed.

If anyone of you wants an image of the disk then send me a PM.