Need help ! Pioneer GM-2200

[Perry Babin]

That all seems OK. Set the meter to AC voltage and measure the voltage on the emitters of the output transistors while driving a strong signal into the amp. Do you read any voltage there?

 

[stuparumihairadu]

That all seems OK. Set the meter to AC voltage and measure the voltage on the emitters of the output transistors while driving a strong signal into the amp. Do you read any voltage there?

i get the following reading....

on all the emitter pins i get - 0.1 ~ 0.2 V..

don`t know if the - (minus sing ) is a god thing .

 

[Perry Babin]

With speakers connected and driving a signal into the amp, do you get any output (including pops or clicks) when you operate all of the controls through the entire range?

IF you place the black probe on the outside shield of the signal source and the red probe on the center pin of the signal source, do you read any AC voltage? Set the volume to the highest setting on the signal source.

 

[stuparumihairadu]

With speakers connected and driving a signal into the amp, do you get any output (including pops or clicks) when you operate all of the controls through the entire range?

IF you place the black probe on the outside shield of the signal source and the red probe on the center pin of the signal source, do you read any AC voltage? Set the volume to the highest setting on the signal source.

so...did that. nothing, not a pop not a thing.
the cable is good.i use between the pc and may receiver at home.

btw : i`m assuming that the tranzistors are good no?after all the measuring etc.

 

[Perry Babin]

Did you measure the AC voltage on the output of the signal source?

 

[stuparumihairadu]

Did you measure the AC voltage on the output of the signal source?

yes I did.

on the samllest scale number 200m , i got the maximum I saw there of about 04.5 V

 

[Perry Babin]

4.5v or 4.5mv?

On the 20v scale, it would read 4.5v if it's actually 4.5v.

 

[stuparumihairadu]

4.5v or 4.5mv?

On the 20v scale, it would read 4.5v if it's actually 4.5v.

I switched the multimeter on the lowest value. 200m (it has 200m 2000m 20 200 and 1000 v) and it showed 04.5 V

 

[Perry Babin]

On the lowest scale, that's not 4.5v. Set it to 20v and check it again.

 

[stuparumihairadu]

On the lowest scale, that's not 4.5v. Set it to 20v and check it again.

on the 20 V I get allmost 0.01....and thats verry rare.

when i swith back to 200m i get the same values i showed you on the other posts

 

[Perry Babin]

That's a very low signal level. Try a different signal source.

 

[stuparumihairadu]

That's a very low signal level. Try a different signal source.

ok.just turned the amp at 3/4 of vlume, and feed signal for the receivers pre-outs to the car amp.

it read 1.50 V @ 20/multimeter, lets say tops .and i blasted it with metallica songs....

turned the amp on, turned the volum knob and still nothing.not a crack, pop, etc.

Any suggestions?

 

[stuparumihairadu]

ok...somebody got a clue what else I can do/check to see what is broken ?

 

[Perry Babin]

With a good signal source (the one that produced 1.5v), measure the AC voltage on the emitter legs of the output transistors again. Do you still read essentially 0v?

 

[stuparumihairadu]

With a good signal source (the one that produced 1.5v), measure the AC voltage on the emitter legs of the output transistors again. Do you still read essentially 0v?

yep.still showing 0~0.1....nothing above doh


so...your answer will be I guess...they are fried??

 

[Perry Babin]

The output transistors are likely OK. They don't appear to be getting driven.

Measure the DC voltage on all of the pins of the op-amps in the amp. Do any have more than a fraction of a volt on their output pins. Look up the datasheet for the op-amps if you don't know the pin configuration.

 

[stuparumihairadu]

The output transistors are likely OK. They don't appear to be getting driven.

Measure the DC voltage on all of the pins of the op-amps in the amp. Do any have more than a fraction of a volt on their output pins. Look up the datasheet for the op-amps if you don't know the pin configuration.

please explain a bit better.

op-amps = operating amps?

where exactly do I find them on the schematic?

by pin configuration you meen B C E correct? to sort out wich are wich.

p.s.

Signal driven into the amp whilst testing?should it be from the same 1.5 v source?

 

[stuparumihairadu]

ok.found them.

only 2 of them (i`m guessing that beeing a 2 channel amplifier, only 2 op-amps needed).

found them on datahseet....i will keep you posted.

Testing would have to be with signal input and speakers conected ?or just signal input no speaker conected?

 

[stuparumihairadu]

Measure the DC voltage on all of the pins of the op-amps in the amp. Do any have more than a fraction of a volt on their output pins. Look up the datasheet for the op-amps if you don't know the pin configuration.

I`ve meassured the 2 op-amp that are put in the schematic just before de output transistors.

One of them puts a reading out of 7.65 V (multimeter set to 20v DC), and the other shows 0~0.1 on the output pins. (nr 2 and nr 8 on the schematics, on datasheet)

p.s. question
if one is broken , can it affect the other one?shouldn`t they be independent of each other?

 

[Perry Babin]

Post the DC voltage on all of the pins of the one with 7.65v on the output.

IC#
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9: