Rockford 460x series one (no output)

[marko]

whilst waiting for parts for my Continuum I thought I'd have a go at fixing this amp that's been sitting my drawer for years!

amp powers up but no output.. these are the readings I took off PWM

1- 5v
2-7.15v
3- 93mv
4- 61mv
5-1.6v
6- 3.4v
7- 61mv
8- 11v
9-4.6v
10- 4.6v
11- 11v
12-11v
13-5v
14-5v
15- 5v
16-3.7v

[Perry Babin]

In the future, please use colons as separators instead of hyphens. Hyphens can be mistaken as a negative sign in some instances.

4600X?

Do you have positive and negative rail voltage on the output transistors?

Do you have positive and negative regulated voltage on the power supply pins of the op-amps?

[marko]

no, 460x similar to this one below but with the x-over cards! (rare beast), will try to determine voltage on outputs but there's not a lot of room to get in there..

Rockford Fosgate series1460 sd

[Perry Babin]

If they're using all IRF540s for outputs, you should see rail voltage on one source resistor and on the tab of one of the output transistors in each channel.

If they're using IRF540s and 9540s, the source resistors will have rail voltage on them.

Is there any corrosion around the electrolytic caps on the input boards?

[marko]

I don't see any corrosion..

I have 24 and -24 on various locations around the outputs..

there appears to be 2 kind of op-amps on the daughter boards behind the rca inputs, TLxxx is one, will have to check them for sure.

[MyNameIsJake]

WOW! I didn't expect my old thread to be brought up. That sure was along time ago...

[seankane]

Originally Posted by marko

I don't see any corrosion..

I have 24 and -24 on various locations around the outputs..

there appears to be 2 kind of op-amps on the daughter boards behind the rca inputs, TLxxx is one, will have to check them for sure.

They are either TL072C or LM833 on the op-amps. More than likely the 10uf 16v surface mount caps are either bad or have leaked on the input board making it very difficult to repair. When they leak the fluid eats up the traces and those boards are obsolete so it is very time consuming trying to repair them. I would remove the input board from the main board and inspect it carefully. Keep us posted on your progress........

[marko]

Originally Posted by seankane

They are either TL072C or LM833 on the op-amps. More than likely the 10uf 16v surface mount caps are either bad or have leaked on the input board making it very difficult to repair. When they leak the fluid eats up the traces and those boards are obsolete so it is very time consuming trying to repair them. I would remove the input board from the main board and inspect it carefully. Keep us posted on your progress........

that's the ones! so could i replace the caps with regular caps and retrace the wiring?

[Perry Babin]

For the caps with solder pads in relatively good condition, I'd recommend using SMD capacitors. You can use regular caps but it's difficult to secure them all to the board (so that they don't put undue stress on the solder pads).

The corrosion isn't always obvious. The black substance between the resistors in the attached image is corrosion from leaked electrolyte.

Before you consider replacing any capacitors (or any other parts), you should determine where the signal stops. If it passes through the input boards and there is no sign of corrosion, you may not need to do anything to the input boards.

You can hardwire the traces.

[marko]

as you know there are 2 preamp boards as it's a 4 channel amp, would seam strange that both boards fail (or not fail) as I have no output on any channel, boards look very clean in comparison to the above image! I'll post voltage on all op amps later if it helps..

Mark.