[Coco] Floppy controller - 7416 failure symptoms? Followup......

Mark Ormond markormond at mtxsystems.com
Sun Nov 14 00:28:38 EST 2010

Ok, I've been trying to get this *&^*&^&* fd-500 controller/disk drive to read and write a good image with no luck.
Today I finally went and visited a good old friend who is a collector like myself.
I borrowed a 26-3029 controller and a trs-80 single external full height drive from him.
Got the setup home, hooked it up to my coco3 and formatted a disk no problems. 
(That itself was a huge surprise, since he had gotten this equipment from a barn several years ago, and had never gotten around to trying/or cleaning it.)
So I powered down and hooked up my fd-500 controller and had format/read problems. So I broke out the iron, cut out those 7416's and tossed in a couple of 7406's. Now everything seems fine, both my original controller and disk drive are happy.

Has anyone ever put together a list of failures/fixes for the coco in a format like Ray Carlsen's for the c64?


It's great for trouble shooting the commodores, Something like that for the coco would rock.

Well, I'm happy I finally have a disk drive, I think I'll image off some infocom games and play.


-----Original Message-----
From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] On Behalf Of Mark Ormond
Sent: Sunday, October 31, 2010 11:58 PM
To: Coco at maltedmedia.com
Subject: [Coco] Floppy controller - 7416 failure symptoms?

Still trouble shooting floppy problems and was wondering if anyone can tell me type symptoms that failing 7416 chips would have in a controller?
It's a fd500.

Also on the fd500 note, does anyone know of a way to add the missing cart connectors? (Pin 37 actually, I need a13.)

I was thinking maybe a rear defroster repair kit to make a contact with 30g kanar wire painted in and super glued running to the rom?


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