Looking a schematic for Electrocompaniet ECI4

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Hello guys,

I have an ECI-3 and I experience the following problem:

1. When I turn on the amp, 5-6 hours long the sound is great.
2. Then begins a distortion on the high frequencies, but only on the left channel.
3. The distortion is volume-independent.
4. After a few hours the problem is over, the sound is normal, again.

Can somebody give me some advice or a service manual to the ECi-3? I live in Hungary.

Regards,

pnimrod
 
And ECI-4 just arrived in our shop from across the country, dropped off by UPS.

Customer says that when he powered it on, "it tried to destroy itself". Visual inspection reveals Q21-Q23 and R620 burnt. Given that it's a PCB-based amp and not point to point wired, a schematic becomes a necessity when signal tracing and troubleshooting.

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My usual search sources came up dry. Does anyone have one that they could share? Much appreciated.
 

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I wrote an e-mail to Electrocompaniet over 2 weeks ago, but have not heard back.

So far, I've replaced Q17, 21, 22, 23 & 24, and R620 I've determined to be 22K based upon tracing where it goes and then comparing with the other channel (the board layout is not symmetrical). I've replaced all of them and did some more static checks. No other faults found.

So I slowly ramped up the AC line on a variac. At some low voltage levels, both channels would display several volts offset, but then would balance out as I went up in voltage to about 65V AC. I made it all the way to 110V and the offset was down to about 1mV in the repaired channel, but the speaker relay didn't pull in. Other channel was negligible offset too.

I fed signal through the amp and looked at the signal on the Zobel network at the output before the relay and it looked good.

Zero offset, but speaker relay doesn't pull in. Hmmm.. so I thought maybe it had something to do with the slow rampup on the variac. At this point I switched off the power and switched it back on a moment later. Relay did not pull in, but after 3 seconds, the output and driver transistors popped. :(

With no schematic, this is going to be a tough one to crack. Was wondering if anyone had luck getting an ECI-4 schematic?
 
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