Good evening guys, my name is Matteo and I'm a new member looking for help, my pre pass Aleph p started to give a strange problem .. while the channel set knob is positioned on channel 1, the channel light remains on 2.and so far no problem since it still reproduces well. The problem arises if I select channel 2, it makes a mechanical noise that I can't describe but comes from inside the case ..
I read somewhere that Mr. Pass answers on a forum, could you tell me what it is?
Thank you very much 👨*🔧
I read somewhere that Mr. Pass answers on a forum, could you tell me what it is?
Thank you very much 👨*🔧
yes, it is the model with remote control, I didn't tell you that the pre has another problem, this time with the volume ... when I rotate the volume knob, there are two points where the signal goes away from the right channel, then I rotate again of a point and everything is in place.
thank you very much
thank you very much
Sounds like a bad microprocessor or logic IC.
The volume control is a series of relays and resistors controlled by the microprocessor. The display and latching are two different IC's so I'm leaning towards the processor. I would check the power supply to the processor as well, its a 5v supply that feeds both the processor and gates.
http://www.kk-pcb.com/a17serv.pdf
The volume control is a series of relays and resistors controlled by the microprocessor. The display and latching are two different IC's so I'm leaning towards the processor. I would check the power supply to the processor as well, its a 5v supply that feeds both the processor and gates.
http://www.kk-pcb.com/a17serv.pdf
thank you so much..
best regard
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Sounds like a relay without enough drive voltage/current to pull in the contacts which is what the chattering is about. Could be the power supply or worse, the drive circuit.
A bad capacitor in power supply would cause AC to pass to the relay which makes them chatter as well
A bad capacitor in power supply would cause AC to pass to the relay which makes them chatter as well
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This sounds like low power supply voltage or the low voltage protection is cutting in. I haven't seen a micro-controller ever fail in one of these except a lightning strike.
Sounds like the relay solenoid gets AC insted of DC. Could also be a bad connection. Maybe better not to provoke this error until it is solved as lifetime of relay may be reduced.
Can you post picture or let me know board revision number?
Thanks for your kind availability
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