HELP, KR 4500 help!

Other Roland synthesizers, modules, keyboards, etc.
Post Reply
missamerica
Posts: 6
Joined: 04:15, 29 June 2011

HELP, KR 4500 help!

Post by missamerica »

I have a kr4500 in very good condition.
The amp amp & pwr board everything clean.

When it works its perfect sound all the programs work no problem with main pwr board best that I can see.
What happens is intermittent turn on the screen is blank and some of the bottom led's stay lit.

No program ,NADA

but sometimes it will go right into startup and play perfectly.
then turn it off and NADA,
bottomr red led's stay lit .
the come back and it might work fine again

I cked all connectors and the pwr supply and amp board seem ok.
First I thought it was (and still may be ) a bad conn.
All ribbon and plug coon look fine and I have reseated all of them.

Tried tapping every where,
I seems as if cold solider joint or something
Then it will turn on just fine.

But when not working turn on & off will not re start and go blank.
the it will work just fine

Could use a set od Schematics for power supply cking all voltages.
My best guess is a loose conn somewhere of a bad cap with ripple on the DC voltage.

Its a very good piano and want to keep it.

Frustrating to have this happen
It seems like a nand gate on a IC chip for switching the circuit to the on state.
The out of the blue it will work again.please help
MissA
Post Reply