nobels tremolo repair

[ward]

Anyone ever etched some 9SIP to 8DIP converter boards?
I can't seem to find KA4558s (9SIP) chip to repair my nobels tremolo stompbox.

 

[gyraf]

wouldn't it be easier to solder dead-bug-style to a strip of sip pins?

 

[gemini86]

+1, think outside the PCB box!

 

[ward]

You're absolutely right, on a second attempt it worked to make something up with some wires.

Now I learned that my diagnosis must be wrong.

I thought IC2 was bad because V/2 was pulled down with the ic in circuit and not without it.
Now I see that V/2 is pulled down with another IC too.

 

[dai h.]

hi, (perhaps you don't need one anymore, but) FWIW NJM (New Japan Radio--also sometimes known as "JRC") make an NJM4558L and NJM4558S (8 pin SIP and 9 pin SIP respectively).

 

[ward]

Indeed it seems like it don't need it anymore.
Without IC2 the unit passes audio in bypass mode.
In effect mode I can hear the effect, but the volume drops to about half the bypassed volume.

With IC2, no sound comes trough in either mode.
And if I measure the supply voltage, V/2 is dropped to about a volt.
This happens with every new IC I tried, (I tried 5532 and TL072 chips.).

 

[pucho812]

have you tried i with a battery vs a wall wart to see if there is a difference?

 

[ward]

I found it,
c14 was the problem.