Yamaha PSR-280 missing random keys

Hi there,
I hope you guys can help point me in the right direction - got a PSR-280 which has an issue where some note keys are not working. Simple, I thought, get in there and thoroughly clean everything. When I was in there, the circuit board and the rubber caps all looked clean, but I did the cleanup anyway, but have been unable to get any of the missing keys working, they seem to be at random places, but mostly on the right-hand end of the keyboard. Tried alcohol, and even specialised electrical cleaner, but no difference.
I think the rubber pads are okay. If I use them manually on ‘good’ key pads on the circuit board they work. There doesn’t appear to be any obvious physical issue with the board, no corrosion, cracks etc.

Is it likely still to be the boards, or is there a known fault with this family of keyboards that cause dropout of keys? BTW, all notes work through MIDI control.

I would appreciate your guidance, and if parts are available, what would I need to bring this keyboard back to life?
Thanks!

Darren
(Melbourne, Australia)

Is there a sequence of missing keys - ie every 12th key
Keys in the PRS280 are scanned in sets of 12

I can’t see any obvious pattern to the missing keys, but I will check to be sure.

These are the missing keys - the ones marked with “I” are intermittent, the white key mostly works, the black key only works if given extra hard push once depressed (then you get quiet note) - the others are dead, no matter how many times or how hard they are pressed.

Can you supply a pic of the circuit board - contact side - faulty section ?

Had a closer look at the PSR280 service manual - you may have issues with some of the rubber contacts not in pace correctly - there is a trick to position the rubber contacts. I made up various tools for a broad range of keyboards but there is a simple way in that case.
To insert the rubber contacts before adding the circuit boards you need to semi-depress all keys to be able to get the rubber contacts underneath the key stop. Get yourself a piece of wood that you can place on the workbench or table you’re working on - place the keyboard on that (keys pointing downwards) so all keys getting depressed a little. Then add the rubber key contacts. Once all the rubber contacts are in - you can “relax” the keyboard and add the contact boards.

Thanks for the suggestions, I agree some of the domes may have been misplaced during cleaning so I re-cleaned and re-seated them and there was an improvement, but I think I am back to the original number of missing keys when I got the keyboard. The very top note is on a separate silicone dome, and while board was out (and connected), I manually pressed the dome to another key pad and it works just fine. So the dome is okay, just the pad, or in this case five pads. https://photos.app.goo.gl/fEqgNzwG5AwwKgUR6 (Latest show of non-working keys)
https://photos.app.goo.gl/NkNxgBC4Qyhinqg2A (The circuit board close up, in three images)

Reading your response your conclusion seems wrong. if the single dome (like your definition) works on other pads - then the pad is good and the other rubber contacts are bad … they do wear over time. Swap a 12-key rubber set to another place - ie take the lowest octave and put it to the very top for example - see what happens.

By the way - what you use to clean the circuit board ? Looks very streaky in the pic - but may be nothing …

Hi, sorry for the confusion, my test was using the final single dome, which is one of the keys that does NOT currently work. Trying that same dome on a known good pad gets a note, so proved the dome itself is good. It does point to the board itself, although it doesn’t look worn or anything. Big question though, is it possible to get that board as a replacement part? As for cleaner, I used Circuit board cleaner “Servisol” which is designed to remove flux, contaminants, and can also remove NA-1002 lacquer - bit tricky to get to every part due to snagging on the solder points, but concentrated more on the pads themselves using cotton buds. I’ll try swapping the set to the other side to see what happens as well.

Okay, further info - swapped the two 12-pad strips from lower end of keyboard into top end. Exact same issue and same keys not working. Cleaned it all once again, still no progress. Big question for Syntaur: Can I purchase a repair kit for the keys and the rubber domes?

Is going to be tough to get any parts - PSR-280 was released (8 March 2001) and YAMAHA usually guarantees parts for 10 years ….

These are the original part numbers:
VV583800 Circuit Board MK-L
VV583900 Circuit Board MK-S

Just asked Yamaha - part (with replacement number) is available to me as a Yamaha Service Centre - but I am in NQ !

North Queensland? Or am I misunderstanding ? :slight_smile:

Just out of interest, what is the cost of the items?

Thanks!

YUP North Queensland and …

VV583800 PC BOARD ASSY MK-L PSR240 L/C : D
Is replaced by below.

VU648102 CIRCUIT BOARD MK-L PSRS710 Currently In stock @ A$15.05 inc. GST

VV583900 CIRCUIT BOARD MK-H PSR260 L/C : D
Is replaced by below.

VU648210 CIRCUIT BOARD MK-H PSRS710 (VU64821) Currently In stock @ A$12.50 inc. GST

Plus shipping to my place about A$18.00

Not bad at all … if you contact maybe Yamaha Service Centre at your place … ?

Thanks mate, and yeah the price isn’t too crazy - will try getting locally if I cn, otherwise I might need you to assist and forward on the items :slight_smile:

where are you then ?

Just down in Melbourne :slight_smile: One “Service Centre” replied to say they don’t sell parts, which was strange. Messaged another down near Geelong, but waiting for reply.

I will be back at some point to resume this search - currently out of work and extracting spare change out of the back of the sofa for now, so I am not ignoring this, just can’t do anything right now, my apologies!

Hi @wernersaurus
I am back :slight_smile:
Still out of work, but may as well get this keyboard done and put back together! Can you tell me best way you can get these items, and sent down to me? Never got a response from the service centres I tried here around Melbourne.
Many thanks!
Darren