hi fellas help with soundstream reference amp again

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hi i currently am working on a old school reference 1000s and original reference 500. for the 1000s the amp powers up then powers down, i'm connecting it to 12v power supply but after less than a second that 12v dropped to 7v. No audio no.
as for the original reference 500 same thing happens but there is audio and power light keeps flashing and audio fades in and out continuously. any help will be greatly appreciated been a nightmare the past 3 weeks about to slam it to the ground and stomp on it till its beyond repair to relieve myself.
 
Russ you need to put it down for a while till your perspective has returned. Electronics will not ease up on you just because your frustrated :)

The amps are powering up but into some failure mode where the supply is being pulled back down by the overwhelming current draw the amps has when its un-muted and trying to be operational. This could be caused by at least a dozen things I can think of off hand. But it all boils down to the fact the amp still has defects inside of it. likely in the channels and possibly due to components that test bad only when rail supply is added.
You might have to digress back to a earlier state by removing whole sections of the amp like all the outputs to get the amp to turn on without the high current draw issues your dealing with. yeah, yeah I know its a lot of work but, you gotta start somewhere and in my mind I would pull all the outputs or at least pull all the emitter resistors at one end feeding the outputs, so they are somewhat out of circuit. Then you go back and look at the amp powered up and look for the errant voltage issues likely driving all those outputs like it is...

You can also pull the FEB's without much pain and this would stop the channels from being driven by the preamp stages. Simple stuff but time consuming I know but this is the load we all bear when we try to bring one of these things back to life...;)

patience's my young friend is the key to successful amp repair...:eek:
 
x2 on the power supply. you may need to use a higher current source to get it to power up enough. please do be careful with those amps. if needed, you could always donate to me. i actually need another 1000s/sx to complete my array. Anyways, the s/sx amps have a few common querks. first thing to pay attention to is the physical aspect. screw all terminals in and pay attention to the led's and pots while you roll the board out. pay close attention to the vertical boards, as the solder tends to break/crack there, and you cannot see it many times. the power supplies, are just large enough to support rated, and can commonly be overran to failure, either by user, or loss of rail signal to the driver ic. i upgrade them all to irf3205 fets. i have read many cases of shorting torroids, but never actually had one of my own go bad. there will be a 1/2, to 2 watt 10, or 100ohm resistor attached to the rail power, near the caps that references to the power supply for regulation. this often cooks with output failur, or preamp/rca grounding issue, iirc. first step is to make sure you can feed the amp to power up, and see if it will idle.
 
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