Rockford Fosgate punch/power 500.2

[Clipped]

If theres any used amp im afraid of buying, its rockford...

working on sms based amps scares the heck out of me due to parts availibility and not being able to read the values on the smd components.

im thinking of picking up two of these amps:

http://ampguts.realmofexcursion.com/...e_Power_500.2/

(is this the 500.2 or 500a2 ??? )

are there any common failures to look out for and anything i should check out on the pcba?

anyone know the acceptable DC offset on the outputs? and the start up current draw/spike?

ive not had very good luck working on rockfords in the past...

real world specs?

any help is greatly appreciated.

[Perry Babin]

This amp (power 500.2) and the 1100a2 are essentially the same amp. These amps are different than most all of the other punch amps. On these, the audio that you see on the output transistors is NOT the audio output. The audio on the outputs rides on the rail voltage. The output is taken from windings on the power transformer.

The amps are generally easy to repair but can be time consuming if you have to replace large numbers of transistors on the MEHSA insulators.

If you're going to buy these from someone you don't know or don't trust, I'd suggest getting photos of the inside of the amps to make sure the boards are in relatively good condition (no holes burned through them).

What sort of problem are you having reading the SMD markings?

[Clipped]

went and checked it out today, opened the cover and saw jump wires all over the place...and nice and crispy char marks...parts of the board were pretty bad, fibers poking out...

i wont be getting them...

but the were 100% cosmetically, if anyone sees these on ebay...be careful