Rockford Fosgate T5002

S Merlington · 2012-09-18 4:31 pm

Just found that Q17 is shorted from legs 2 to 3

S Merlington · 2012-09-18 4:46 pm

In diode Check the LM337T out of the board measures

Legs 1-2:0.640
Legs 1-3:0.724
Legs 2-3:0.770

Probes reversed

Legs 1-2OL
Legs 1-3:OL
Legs 2-3:0.516

Does this look ok or oes it appear to be leaking between legs 2-3 ?

Perry Babin · 2012-09-18 9:42 pm

This isn't a transistor and can't be checked in this way. The LM337 is an integrated circuit that likely has several dozen transistors and resistors in it. You could look up the datasheet if you're interested.

Post #20 questions?

S Merlington · 2012-09-21 2:30 pm

R63 measures:1.135 Its marked 1301

R65 measures:120.0 Its marked 1210

C35's negativee terminal reads 0.46 volts

Perry Babin · 2012-09-23 8:51 pm

1.135 what? It's rare to have a meter that will read to the thousandths of an ohm.

S Merlington · 2012-09-24 2:05 am

Measured it again to be sure and R63 measures 1.137 on my meter

S Merlington · 2012-09-30 6:59 am

Ok I got the amp to stop burning resistors..

Wondering what 2 diodes i lift to disable the protection in the left channel They are the 1000 series patrts?

Perry Babin · 2012-09-30 7:37 am

D1002-D1005.

S Merlington · 2012-09-30 4:15 pm

Lifted D1002 and D1005 Left channel is still very distorted ..

I have both + - rail voltage and both + - 13 volts of regulated voltages on op-amps

Any ideas what to check next?

S Merlington · 2012-09-30 5:32 pm

Ok i got both channels To produce Audio..

Problem is both channels a have very distorted output ..

I lifted D1002, D1005, D2002 and D2005

No change in the distorted output..

I cleaned all switches ...

I have Both + - rail voltages on both channel outputs also have + - 13 volts of regulated voltages on all op-amps...

Protection light is barley lit on this amp but still lit up ..

Any ideas where to check next to see if i can find the problem of the distorted output ??

Perry Babin · 2012-09-30 10:25 pm

Post a photo of the distorted waveforms.

S Merlington · 2012-10-01 1:42 am

Both wave forms look the same ..

Scope set to 10ms .1 volts div with a 100hz sine wave

Perry Babin · 2012-10-01 1:51 am

Do you have clean audio on pin 7 of U103 and U203?

S Merlington · 2012-10-01 3:44 am

Yes I have clean audio on both U103 and 203 on pin 7

Perry Babin · 2012-10-01 9:05 am

Do the bias controls work?

What is the DC voltage on all 3 terminals of Q1021?

S Merlington · 2012-10-01 12:46 pm

Q1021

Base:44.3
Collector:14.6
Emitter:44.6

Bias controls are not working ..

Perry Babin · 2012-10-01 5:50 pm

DC voltage on Q1009?

S Merlington · 2012-10-01 5:56 pm

Q1009

Base:13.29
Emitter:13.98
Collector:12.41

Perry Babin · 2012-10-01 6:10 pm

Post the DC voltage on Q1022 and Q1016.

S Merlington · 2012-10-01 6:20 pm

Q1016
Base: starts off at 13.89 volts and drop to 3.05 vols
Collector:44.5
Emitter:starts off at 13.89 volts and jumps all over in the 12 volt range

Q1022
Base:45.1
Collector:45.2
Emitter:44.7

Rockford Fosgate T5002

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