Hello everybody!
I bought an used, unworking, Celviano AP-60R (european version, 220v) and I'm beginning to restore it.
Piano turns on. but only power led and lcd backlight.
No sound from speakers, no activity on lcd panel, no keys on panel working, all leds on panel always off.
I get service manuale, and begin my works:
First check at voltages reveal a dead IC403 on power board (7805 regulator) that I replaced, also I replaced exhausted capacitors.
But still same behavior.
So, following service manual dataflow, I suspect problem is in JCM660-MA1M logic board. Unluckily this replacement part is not more available, so I must try to repair it myself.
I checked both CP1 and CP2 Clock check point, that results regular, I replaced C29,C30,C31,C45,C46,C47, and checked also reset line at IC7 pin 8.
Using a logic probe I checked activity at rom and ram chips, all seems regular.
My question is: what kind of ic could cause that display, leds, sound isn't working?
I checked amplifier sending signal from a generator at CB connector, pins 11 & 12, sound and volume control are working.
What I should do?
I don't know where to find replacement part, only part available is HD6473048F16 CPU, but I'm not 100% sure it can solve problem. because of rom-ram activity. and prefer to wait before to try (not so easy) replacement.
If anyone can give help, I appreciate so much.
Best regards from Italy, Enzo.
EDIT:
Further investigations reveals that LDB4-LDB7 lines (that drives display) are stuck at 0 and 1 and lines KI0-KI7 (that explores panel) are completely dead.
All these lines are connected to CPU, Hitachi HD6473048F16, as suspected before.
But, studying better this CPU, it has an internal PROM, programmed by end chip user, in other words from Casio, and obviously his content isn't available.
So, also I can find a HD6473048F16 to substitute, it cannot works because missing of internal program by Casio.
In other words, entire piano must be thrown away because of this...
But I ask, if Casio doesn't to sell spare parts for these obsolete models, why don't publish internal programs so anyone can repair it?
