Hi. Not our mainstream line of work - we work with digital mostly. Will study the schematic found on the internet. The output darlington transistors appear to be ok. Even with no input, the output is extremely loud with static / crackle / pop. Any ideas? Will post more details and fix as we continue the review. Have not checked the main power supply rails yet (+-40V and +-16V).
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What model number? Got a schematic to boot with it? -
Thanks so much for replying. No, could not find one..yet. Will share the full details on Monday (or sooner if we run back to the office). Still fixing a Fender 212R which is slightly different in the schematic than the public ones on the internet. Has noise even on clean input. Static / distortion with a mind of its own. The power rails are stable. Amp appears to be ok and loud. Replaced most of the pots and did replace each connector with little improvement. Working with a 1 khz tone from our scope as input and tracing as we go.Comment
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Attached.
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Found the following on internet which may be the scematic - will confirm it on Monday.
Symptoms are:
with or without input, blasting loud random static / snap / crackle pop. Volume control has no impact on the output noise. Cut the darlington output transistors to measure in diode mode and they appear to test out fine and without a short. Have not yet injected a 1khz tone into the input to monitor with a scope.
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Check with the oscilloscope what goes into the PA. Would be my first step.Comment
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Hello,
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Hi forum.
I'm working on a macbook pro, model a1708, that is running extremely slow.
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