Ah crap - Bought S/H MPK issue with keys

[deevey]

I went and bought a second hand MPK yesterday for a decent price (so I thought) in the knowledge that a few keys were not working properly .. pressing hard on one of them and I got a faint sound so was pretty sure it was the regular "no-contact" issue between the plastic key and the rubber contact. However not the case.

Took the unit apart today, and checked the contacts - even went so far as to strip down to the copper and short one of the keys to check for anything and nada, zip, dead air (on a working key I get signal doing this)

Any ideas what else could be at fault - guessing it "might" be the keybed PCB issue (all the diodes check out though and tracks are not broken) or a possibly a twisted or loose component elsewhere on one of the boards

Anyone with a similar issue have any luck repairing before I spend a bundle on a service center ?

[deevey]

I went and bought a second hand MPK yesterday for a decent price (so I thought) in the knowledge that a few keys were not working properly .. pressing hard on one of them and I got a faint sound so was pretty sure it was the regular "no-contact" issue between the plastic key and the rubber contact. However not the case.

Took the unit apart today, and checked the contacts - even went so far as to strip down to the copper and short one of the keys to check for anything and nada, zip, dead air (on a working key I get signal doing this)

Any ideas what else could be at fault - guessing it "might" be the keybed PCB issue (all the diodes check out though and tracks are not broken) or a possibly a twisted or loose component elsewhere on one of the boards

Anyone with a similar issue have any luck repairing before I spend a bundle on a service center ?

*edit* might have found a solution here &

[mdcdesign]

For a more long-term solution, see if you can get your hands on a conductive ink pen Eventually graphite from a pencil will dissipate and you'll be back to square one.

[deevey]

Well I bought the Re-Carboning Kit, the kit works just great and the keys that were working already are more responsive.

And while I had it in pieces I got some rubber insulating tape (designed for sealing cables underwater) and modded the pads which are now simply AWESOME.

However - the keys that were not working are still not working .. checked and double checked all the resistances, diodes ... tracing back everything it looks like theres an intermittent break on the track leading up to a junction where 5 keys meet. Must be a really really small break as it was working (kinda) every so often before .. ugh.

I think I should be able to bypass it end to end and hopefully it sorts thing out.

On the upside every remote control in the house has really responsive buttons as well now (@$30 for the kit I was gonna fix everything I could get my hands on).

[deevey]

Well after some epic failure with both the carboning and trying to jump the board and still no signal, I've decided to bite the bullet and order a new keybed from Akai (who are absolutely fabulous to deal with BTW).

I got some photos of the pad mod that I'll throw up soon enough as it works absolutely flawlessly and would be well worthwhile for everyone to do for the $5 in materials

Armak Butyl Self Fusing Rubber Tape is the stuff I used