Reamer xmas present wierdness ??

[MartyMart]

I've built another reamer on perf for a friend ( third one! ) and have a lot of hum, very "distant" overdrive which seems to work with pot changes, its just a tenth of the volume its supposed to be !!
Here's the op amp readings:

Pin 1-- 7.41v

Pin 2-- 4.32v

Pin 3-- 2.14v

Pin 4-- 0.00v

Pin 5-- 3.74v

Pin 6-- 4.42v

Pin 7-- 9.47v

Pin 8-- 7.37v

Battery is 9.47v

Vol pot is a 500k, as thats all I have around.
Any Ideas folks ?? I'm a bit bemused, wiring etc is all A-OK !

Many thanks,
Marty. :oops:

[petemoore]

I've built another reamer on perf for a friend ( third one! ) and have a lot of hum, very "distant" overdrive which seems to work with pot changes, its just a tenth of the volume its supposed to be !!
Here's the op amp readings:

Pin 1-- 7.41v

Pin 2-- 4.32v

Pin 3-- 2.14v

Pin 4-- 0.00v

Pin 5-- 3.74v

Pin 6-- 4.42v

Pin 7-- 9.47v

Pin 8-- 7.37v

Battery is 9.47v
 I'm assuming this is a dual OA. All the input and output pins of the OA's that are around 1/2v of supply are 'good'. Battery Voltage is  good.
  dual,,,is it a single OA ?

Vol pot is a 500k, as thats all I have around.
Any Ideas folks ?? I'm a bit bemused, wiring etc is all A-OK !

Many thanks,
Marty. :oops:

[MartyMart]

Thanks Pete, its a single op-amp,  Panasonic NE5534AN  this sounds great in the other two !
Vol pot too Huge ? I may have a 220k somewhere. . .
Marty.

[petemoore]

Ok single
 Pin 7 V+ should read liek battery
 Pin 4 should be ground
the rest
 Input and output pins should be near 1/2v. any that aren't must have a miswire or misvalued resistor, cold solder, bridge or other problem.
 I'd be looking around pin 3 and pin 5.

[MartyMart]

Ok single
 Pin 7 V+ should read liek battery
 Pin 4 should be ground
the rest
 Input and output pins should be near 1/2v. any that aren't must have a miswire or misvalued resistor, cold solder, bridge or other problem.
 I'd be looking around pin 3 and pin 5.

Thank you Pete!  as pin 5 is not connected, then I'll check the cap/resistor network around pin 3 and give everything a re-solder, I tend to be a little "Light" on the solder, all my wiring hardly looks like it has any on it !!

Marty.