Soundstream Reference 604

[Herb009]

hi,
i´m trying to repair a referenc 604 amp. One of the four channels doesn´t wor. I´m not sure what´s wrong with it.
If i would have a schematic it would be easier.
Could anyone help me and send a schematic.

My e-mail adress is
Click here to email me


Thanks,
Herb.

[Perry Babin]

Check all of the switches. Virtually all of the switches in these old amps have problems. Work all switches back and forth several times to see if the audio returns.

[marko]

sounds like an outputs blown, fairly common and easy to fix if your handy with a soldering iron.

[shagone]

Wouldn't the amp go into protection mode if the outputs in one channel were blown? maybe not if they were blown completly open instead of shorted but i have not seen this happen.

[marko]

on some of the earlier s/s amps each output has a fuse and blows when an output goes but still allows the other outputs to play, every scenario is unique i guess and depends on the exact damage the amp has...

[audiobahnkid592]

if you still need them i meight be able to dig them up

[Herb009]

Thanks to all of you for your assistance.

In the meantime I have checked all the switches but with no result.

I think the output is not blown, because I measured at the pins of the Darlington-Transistors an found out, that at the not-working channel there is no signal. (I compared it with the three other working channels and there was a signal like that i connected to the inputs)

I found two fuses and both are ok.

I is long time ago since I have repaired my last amp but with your help, I am optimistic that I can do it.
But first of all the schematic would be a great help.

To audiobahnkid592:
I would be very thankful if you could sent me a schematic or other technical documetation of the amp.

My e-mail is herbert.brunmeier@freenet.de.

Herb009

[Perry Babin]

I don't have the schematic for this amp but it appears that it uses the driver board with the 3067 diferential amp transistor. If so, the input to the driver board (near the outputs) is the center land/pad (where it connects to the main board). Do you have audio there (or on any pad of the driver board) on the dead channel?

Compare to a working channel.