128DCR Trouble Shooting

roushinator · March 05, 2010, 12:15 PM

So i need a little help. Just got my 128CDR and it powers up fine. It will go into C64 mode fine. But when i try to load a game it sits there. Drive does not try to access the floppy. It says "searching for" and nothing happens. Any ideas. Thanks.

Ryan

dr.v · March 05, 2010, 02:21 PM

Ryan - how you approach the troubleshooting will be a function of what other equipment you have lying about. Do you have another 1571 drive? I would try swapping out the mechanisms and see how that goes.

Tom

cbmguy · March 05, 2010, 02:53 PM

Have you checked the CN12 interface on the board just behind the drive? It's the one with the black cable attached to it. it it's not properly installed (or not installed), this problem you're having will happen.

C

roushinator · March 06, 2010, 01:03 AM

Quote from: cbmguy on March 05, 2010, 02:53 PM
Have you checked the CN12 interface on the board just behind the drive? It's the one with the black cable attached to it. it it's not properly installed (or not installed), this problem you're having will happen.

C

It looks to be installed correctly. the red cables on the plug are on the side near CR103. The Green light on the drive does come on when i power the computer on.

cbmguy · March 06, 2010, 03:15 AM

If the CN12 is properly connected, then I really have no other help for you other than the drive worm might be stuck. A quick little push with your finger will usually unjar that. The data cables on the side of the drive would usually give you some sort of error. Could also be the logic, as well. IC102 (I think) is the chip that is the drive's kernel. I wish I could help more, but I don't know too much about the '71d other than that.

C

pearsoe · March 06, 2010, 04:31 AM

You might want to go through this article as it relates to 1571 drive troubleshooting and solutions. The problems discussed are common with the 128D also:

http://www.commodore128.org/index.php?topic=2236.msg8996#msg8996

roushinator · March 06, 2010, 04:54 AM

Quote from: pearsoe on March 06, 2010, 04:31 AM
You might want to go through this article as it relates to 1571 drive troubleshooting and solutions. The problems discussed are common with the 128D also:

http://www.commodore128.org/index.php?topic=2236.msg8996#msg8996

Cool. Thanks for the link.

redrumloa · March 06, 2010, 07:36 AM

It might be pushing a little bit on each socketed chip with your thumb to make sure they are seated properly (after you touch the metal case to make sure you are statically discharged). Maybe the CIA or another chip is not making contact? Just a guess.

roushinator · March 14, 2010, 11:05 AM

So i could not see anything obvious that was wrong. So i got one of those diagnostic carts. this is what it says....

Says 6526 and 6581 chips are bad. So what do i do now? Get some new chips? This will be my first attempt in repairing a C128 so any tips and advice will be helpful. Thanks.

I let the test sit there for a few minutes. It never said it was done just kept cycling over and over.

airship · March 15, 2010, 02:05 AM

Pry the chips up just a little with a very small screwdriver, then push them back down in their sockets. That might fix 'em. (Do be careful about static, as redrumola said above.)

Unfortunately, the SID and CIAs are very fragile - I wouldn't be surprised if they actually are all dead.

dabone · March 15, 2010, 03:28 AM

If that cart is like the c64 one, the chips will report bad without the test harness.
I'm looking for a copy of the diag cart image for the 128, any chance anyone has a copy to share?
(I want to try it in a easyflash).

Later,
dabone

BigDumbDinosaur · March 17, 2010, 02:54 PM

The first thing I'd do is immediately after power up but before attempting any kind of disk operation would be:

100 OPEN 15,8,15
110 INPUT#15,E,E$,X$,Y$
120 CLOSE 15
130 PRINT E,E$,X$,Y$

Run the above and and see if you get a response from the drive. Right after power up or a hard reset, you should get a DOS version. If you do, that rules out a lot of the electronics. If not, you've got some troubleshooting to do.

roushinator · March 23, 2010, 11:14 PM

Quote from: BigDumbDinosaur on March 17, 2010, 02:54 PM
The first thing I'd do is immediately after power up but before attempting any kind of disk operation would be:

100 OPEN 15,8,15
110 INPUT#15,E,E$,X$,Y$
120 CLOSE 15
130 PRINT E,E$,X$,Y$

Run the above and and see if you get a response from the drive. Right after power up or a hard reset, you should get a DOS version. If you do, that rules out a lot of the electronics. If not, you've got some troubleshooting to do.

Okay i will try that. Thanks.