Hi folks,
Per headline My 640A has refused to turned back to normal playing mode from the protection mode. I tried cutting it off to all power for a few days, which always did the trick until this time, then eventually this morning I disconnected it from everything but it still won't turn back on. I am going to assume that something inside has busted.
Anything else you can recommend to try without opening the thing up before taking it to a repairman or looking for a new amp?
Thanks!!
Per headline My 640A has refused to turned back to normal playing mode from the protection mode. I tried cutting it off to all power for a few days, which always did the trick until this time, then eventually this morning I disconnected it from everything but it still won't turn back on. I am going to assume that something inside has busted.
Anything else you can recommend to try without opening the thing up before taking it to a repairman or looking for a new amp?
Thanks!!
Have you searched existing threads that discuss this model? There are several known problems and most will eventually cause it to trigger protection mode which as the name may suggest, means there is a fault that can't be fixed just by resetting or bypassing the protection, as we may assume or hope for.
This thread I recall, has suggestions, one solution and links to other info that may help in finding which particular fault(s) could be your problem: https://www.diyaudio.com/coommunity/threads/cambridge-audio-640a-v2-0-service-manual.309273
This thread I recall, has suggestions, one solution and links to other info that may help in finding which particular fault(s) could be your problem: https://www.diyaudio.com/coommunity/threads/cambridge-audio-640a-v2-0-service-manual.309273
Yes, I did, and the fixing mentioned in those threads all involve "opening the thing up". I dont know how to replace a transistor etc so my question is just whether there's anything else I maybe able to try beside turning it on/off which has worked for me before.
Well, no. That re-starting solution just resets the protection logic in the hope that the problem was just a conflict or other temporary logic fault which somehow disappears on subsequent uses. Maybe there's also a hope that a component/connection failure might somehow repair itself meantime.
It's reasonable to expect problems to go away in a software environment where conflicts are legion but unfortunately, hardware failures are physical damage which means actual repairs. I have come across many microprocessor controlled products that seem to have logic problems and faults that vanish before a service tech. has a chance to see them but they still persist. Often, the fault was the microprocessor clock as the ceramic resonators used for the purpose, are prone to failure.
In any event, the lid will need lifting and a competent tech. should at least verify the MCU is working properly and stable. This isn't a job for a newbie or your typical DIY bodger with no oscilloscope.
It's reasonable to expect problems to go away in a software environment where conflicts are legion but unfortunately, hardware failures are physical damage which means actual repairs. I have come across many microprocessor controlled products that seem to have logic problems and faults that vanish before a service tech. has a chance to see them but they still persist. Often, the fault was the microprocessor clock as the ceramic resonators used for the purpose, are prone to failure.
In any event, the lid will need lifting and a competent tech. should at least verify the MCU is working properly and stable. This isn't a job for a newbie or your typical DIY bodger with no oscilloscope.
Take it to an authorised or at least qualified repair work shop.
A list of authorised repairers in your area, will be available through the Cambride Audio web site.
A list of authorised repairers in your area, will be available through the Cambride Audio web site.