CPCWiki forum

General Category => Technical Support => Hardware related => Topic started by: Liartes on 09:57, 24 October 20

Title: CPC 6128 internal disk drive not responding (not a belt issue)
Post by: Liartes on 09:57, 24 October 20
Hello !
My CPC 6128 have a strange behaviour regarding the disk drive. The drive LED is light up but dim, and nothing happen at all when I run the CAT command.The disk drive is good, I tested it with FD-1 hardware sometime ago. The CPC 6128 disk drive controller is working when I am using a B drive.
The 5V rail drop to 4,4V in usage and the 12V rail drop drop to 10,30V when invoking CAT.
I didn't read anything about this problem in the service manual. Maybe the capacitors on the upper-left corner of the board need to be replaced, but I would like to read your opinion before engaging myself in the soldering job.
Title: Re: CPC 6128 internal disk drive not responding (not a belt issue)
Post by: Bryce on 10:45, 24 October 20
Have you checked the entire drive PCB for dry joints?

Bryce.
Title: Re: CPC 6128 internal disk drive not responding (not a belt issue)
Post by: llopis on 16:35, 24 October 20
I would help to know more details. Does it hang forever? Does it print an error message? Does it just return to the "Ready" prompt? Does it spin up? Does the head move?

If the drive is fine, I would suspect a problem with the cable or with the floppy disk controller.
Title: Re: CPC 6128 internal disk drive not responding (not a belt issue)
Post by: Liartes on 09:08, 25 October 20
@Bryce (https://www.cpcwiki.eu/forum/index.php?action=profile;u=225) : The drive is working fine when used as external B drive, but I have another disk drive that I can test in internal configuration in order to hint in the dry joints direction.

@Llopis :  The CAT command is followed by "Drive A: disc missing Retry, Ignore or Cancel?". It does not spin, the head doesn't move, not even an electrostatic sound. Powering the 12V rail or not does not seems to change the behaviour. The power is correctly delivered to the disk drive, measured with my voltmeter. I also tried with external PSU, nothing changed.I assumed the floppy disk controller was shared between the internal disk drive and the external disk drive, and the external disk drive is working alright. I can probably try with another internal flat cable, then test for the "motor ON" and "read" signals on the motherboard ?

EDIT : Mystery solved : The disk drive is faulty. When I replace it with another one wired as internal disk drive, this is working fine. Something went bad in the couple of months I kept it stored... Dry joints here I come !
Title: Re: CPC 6128 internal disk drive not responding (not a belt issue)
Post by: Bryce on 14:07, 25 October 20
Due to your " It does not spin, the head doesn't move, not even an electrostatic sound" statement, the most likely place to look for dry joints would be the four pins on the power socket.

Bryce.
Title: Re: CPC 6128 internal disk drive not responding (not a belt issue)
Post by: Liartes on 09:18, 28 December 20
Follow up : I finally get the time to reflow the four pins power socket and you were right Bryce ! Working flawlessly for a longplay session on Mortville Manor, which require very frequent disk loading.
Title: Re: CPC 6128 internal disk drive not responding (not a belt issue)
Post by: Bryce on 11:12, 28 December 20
Glad you got it sorted, happy gaming.

Bryce.