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Desperately seeking schematic for Citronic SA 400
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Jod Clark View Drop Down
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Joined: 26 December 2011
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Points: 7 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Jod Clark Quote  Post ReplyReply Direct Link To This Post Topic: Desperately seeking schematic for Citronic SA 400
    Posted: 20 July 2025 at 12:07pm
Hi folks, new to posting, not new to lurking and, particularly, letching at all your lovely amplifiers!

I am desperately in need of a schematic and / or service manual for a Citronic SA400 power amp so I can relive my youth a bit.

Is anyone able to help me please?

The problem I have is one channel gets very hot very quickly when idle and connected to an 8 ohm dummy load. The other channel is fine. I mainly need to know rail voltages and bias adjustment procedure.

Thank you all in advance
Jod C


Edited by Jod Clark - 20 July 2025 at 12:08pm
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djeddie View Drop Down
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Points: 4125 		Post Options Post Options   Thanks (0) Thanks(0)   Quote djeddie Quote  Post ReplyReply Direct Link To This Post Posted: 20 July 2025 at 2:26pm
Why not just measure the good side?
Chas n Dave : it's like Drum and Bass but with beards.             E=mc² ±3dB
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Jod Clark View Drop Down
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Joined: 26 December 2011
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Points: 7 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Jod Clark Quote  Post ReplyReply Direct Link To This Post Posted: 20 July 2025 at 2:34pm
DJ Eddie, thank you, I have already measured everything I can whilst it's in circuit, the problem shows up on my 'scope as a steadily increasing voltage across the emitter resistors as the amplifier warms up, but can't trace it back to any obvious fault. There's no oscillation in either channel. Amplifier board is hot enough to start the cooling fan within around two minutes of switch-on. There is no DC offset on the output. It's all very mysterious.

Best,
Jod C
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Jan-2T View Drop Down
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Points: 137 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Jan-2T Quote  Post ReplyReply Direct Link To This Post Posted: 22 July 2025 at 8:39am
You can switch the components over from the "good" side, one by one, until the fault is gone.
Music!
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Pinyorouk View Drop Down
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Points: 593 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Pinyorouk Quote  Post ReplyReply Direct Link To This Post Posted: 22 July 2025 at 6:22pm
Originally posted by Jan-2T Jan-2T wrote:

You can switch the components over from the "good" side, one by one, until the fault is gone.

Or.kill the good.one in the process.
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