Electronics repairs, the lethargic_man way

[lethargic_man]

Yesterday I fired up my Music 4000 keyboard for the first time in a year. It was time, I reckoned, to have a practice to make sure I didn't forget how to play the piano. (I first took the keyboard to Edinburgh when I discovered I'd gotten so bad I couldn't even play a scale keeping my hands together.)

Unfortunately, I soon discovered every eighth note along the keyboard wasn't playing. A visual inspection of the ribbon cable revealed a broken wire close to the keyboard end. So I cut the cable at the break, and took the keyboard apart to reinsert the new cable end. Hmm, little plastic lugs holding the top of the ribbon cable terminus to the bottom. Does this lever outward? *snap* Oops! Five minutes later, I snapped the other one too. There was only one solution: brown tape, and lots of it!

Ten minutes later, I'd got the keyboard back together, with only one screw left over, switched back on my BBC Micro, and gave it a try. No longer was it the case that one note in eight wouldn't play. Now three notes in eight don't play. Aargh.

I suspect I failed to make sure all the cables in the ribbon cable were properly perforated. Ah well; further investigation will have to wait; I ran out of time yesterday, and headed off to an Marom eighties nostalgia evening (supplemented, at my insistence, by a bit of seventies nostalgia when I discovered Roni's Dangermouse DVD also featured Chorlton and the Wheelies).

Update: My guess was indeed the case; the keyboard is now fixed.

Comments

[compilerbitch.livejournal.com]

Standard practice for beeb-era ribbon cables is to go along the connector with a pair of pliers squeezing it together every few millimetres. It is essential with a new cable, and fixes 98% of problems with older cables.