Need help ! Pioneer GM-2200

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hm...this might be funny.....

i ain`t geting no reading on the multimeter (ohm mode) between the fuse on the remote cable.

0.8 ohms between one pin on the fuse socket and the tip of the cable, 0.8 ohms between the other tip of the fuse socket ant the tip of the cable..... nothing between the pins of the socket.
 
I don't think this amp has a protection LED. The power LED is red. Have you tried connecting a head unit and speakers to it to see if it produces audio?

yep.
It fixed it up to a battery, gave it music from the phone, but still no sound.

n00b question.

looked it up on how to check tranzistors.

B C E - B-C conducts, B-E conducts, C-E does not conduct.
now, i`ve tested them again and I get this results.

(board facing twoards me tranzistors in the upper part )
Tranzistor nr 1 nr 2 nr 3 nr 4

the nr 1 and nr 4 all show readings on the multimeter in both cases (BC/BE )
their Q560 and Q559 on the second page of the pioneer-gm1200-2200 schematic.

on the nr 2 and 3 I get no reading on the BC reading on none of them.
now I read on the internet about this and I think its called a "darlington pair"
the 2 that work are npn and the 2 that don`t work are pnp.

do I have to check them differently?or is it now clear that because of the fact that the multimeter shows no reading on the BC probing they are broken and need replacing?
 
With the amp powered up, what is the DC voltage on all 6 legs of the two output transistors in either channel?

Don't let your probes slip and short between the terminals. Place the black probe on the ground terminal of the amp. Disconnect the RCAs and the speakers.


probing only worked on one leg. (base).if this was how it was supposed to be done.

it showed a value of 0.34 on both tranzistors on both channels.

i`ve worked out the bias and its now as it was when I first tempered with it.

switching the bias incresed the values at arround 0.54 (allmost at maximum switch).
now I remembered how they were switched and put them like they are now.at minimum value.(as they came :) )
 
Are you saying that the only leg with any voltage was the base and it only had 0.34v?

What scale was the meter set to?

Measure the DC voltage on one of the power supply transistors.


I pun the negative probe on the ground terminal of the amp.
then I went and checked each pin of the output tranzistors on each 4 of them.
I only got a reading on the Base pin of 0.34v.the multimeter was set on dc 20V. (it has a scale of 200m, 2000m , 20 200 and 1000).


hmmm...where do I find the power suply tranzistors?are they the little ones bwttewn the 2 output tranzistors?cause they showed a value of 0.94 v.
 
Set the meter to the next higher voltage and measure the DC voltage on the output transistors again. If you don't get any readings on anything other than the bases, measure the voltage on one of the power supply FETs (Q901-Q904).


ok/found them all.

1.9-2.0 v on the base pin and 12 v on the collector pin. 0 on the emitter on the tranzistors Q901-902-903-904.

0.3 on the base pin and 30.3 (30. something) on the collector. 0 on the emitter.
 
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