DDI-1 Not reading discs

[Jay king]

Hi There.
My DDI- 1 is just coming up drive A: Disc missing
Retry, Ignore or cancel

To be honest ive only had it 5 minutes and never used it.
Am I doing something wrong, or does it need a clean maybe?

Cheers

Jason

[Dagger]

May need a new belt

[||C|-|E||]

If you hear the motor spinning while the message is displayed, then is probably as Dagger says, the drive belt. You can buy a replacement on e-bay 

[Bryce]

Give us a better description of what you have. Does the DDI-1 have an FD-1 connected? Is the LED turning on / flashing? Does the disc spin? Can you hear the head moving?

Bryce.

[richy]

Hi all!
Since the subject just meets my problem I reuse this thread - hope this night be okay :-)

Suddenly my DDI stopped working. Disc missing only - there is a new belt mounted. The disc spins but the head doesn't make any tries to move...

Strange: same result with another FD-1 and also with a TEAC 5 1/4" drive... Some days before all (okay didn't manage to use 5 1/4" but 3" was good) was fine and I could even boot up CP/M but now my 464 just keeps missing discs :-(

Could this be a controller or cable problem? Has anyone hints for me what to look for?

Thanks for your help and best wishes from Osnabrück!
Richard

[Bryce]

Most likely you've damaged the flat cable when removing it.

Bryce.

[richy]

Thanks for the hint Bryce. Just build a new cable with fresh parts. Checked it but still the same :-(
Any other ideas what to check/do? I have somehow the impression that my interface is gone :-/


Richard

[Bryce]

Have you a multimeter to check each connection?

The signal that moves the head is called "STEP" in the schematics. It goes from pin 8 of one of the 74LS38 in the DDI-1 (may be a 74LS00 on some versions) via pin 15 on the flat cable. Make sure this connection is complete. If it is, the 74LS38 may have died and need to be swapped. The 74LS38 is also being driven by a 74LS08 (IC105 pin 8 ) so you need to check this chip too, however the 74LS38 is the more likely candidate.

If this isn't something you can do yourself, you can send it over to me for repair. Ignore the random flag in my profile, I'm actually in Germany too.

Bryce.

[richy]

Bryce! You were fully right, my cable was not correct connected, two wires were dead.
So happy my discs are working again!
Thank you very much for your hints!
Richard


BTW: how long might a cable for a disc drive be to work properly?

[Bryce]

Hi richy,
     cool that all is working again, congratulations. Regarding the wire length... Suprisingly long actually. I've seen cables over 3 metres that worked reliably. As long as the 1's (which should be 5V) are still about 2.5V or more at the other end then it should work ok. The data rate is relatively slow, so latency / capacitance problems won't occur at that length. Just make sure that the cable isn't passing very close by anything that transits rubbish such as a PC / monitor / TV / fridge.

Bryce.