With the black probe on the amp's ground terminal and the red on the right negative speaker terminal, do you read positive or negative 40v DC?
I don't have this diagram. The one I have labeled 550S is a different board. If no one else has it here, you'll need to get a copy from Rockford and email it to me.
babin_perry@yahoo.com
babin_perry@yahoo.com
You need to check those transistors with the meter on diode-check and no power applied.
If you don't know how to test them, use the applet linked from the following page.
Basic Amplifier Repair - Transistor Test Applet Link
If you don't know how to test them, use the applet linked from the following page.
Basic Amplifier Repair - Transistor Test Applet Link
In order from top to bottom...
* shorted/leaky
* open base to emitter
* probably OK but slightly leaky collector to emitter. Could have been caused by touching the probes
* also appears to be leaky
I'd suggest replacing all of them.
* shorted/leaky
* open base to emitter
* probably OK but slightly leaky collector to emitter. Could have been caused by touching the probes
* also appears to be leaky
I'd suggest replacing all of them.
I'm looking at some of my options (on my phone at the moment) and notice one has a much higher power dissipation rating. Should this be a viable choice?
MMBT3904LT3G ON Semiconductor | Mouser
MMBT3904LT3G ON Semiconductor | Mouser
I installed and checked everything and it seems the only thing that has changed is the right channel output is now -44v instead of -40v.
I guess this amp is making up for how easy the 150 was to repair!
I guess this amp is making up for how easy the 150 was to repair!
Are you sure you don't have an open source resistor or a bad output?
Sometimes they can fail during replacement.
Sometimes they can fail during replacement.
Anything is possible. I haven't had much time for thorough testing. I may need to pick up a magnifier to look over some of the delicate solder points. They look great to the nekkid eye but I also realize that type of soldering shouldn't be done after consuming nearly a pot of coffee ...
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