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In Topic: MA5000VZ fans running fast
19 February 2013 - 03:30 PM
Ah, never seen any with long pins. Any amps I've seen with this problem are usually rather old by then. I always check the joints even if the fault is not ostensibly on the output modules.
In Topic: MA5000VZ fans running fast
30 January 2013 - 03:03 PM
Hello Alain, yes the previous amplifier had the same symptoms, but this is a different amplifier and it isn't the flat ribbon..it was the first thing I checked!!
This was a difficult one. I discovered that the +ODEP voltage was perfect at 12.6V...however I spotted today that the voltage was positive with respect to 0V...it should be negative -12.6V !! So we had a hard odep fault on Ch1.
After 3 long days of testing, swapping chips, testing for leaky capacitors etc., I finally found the fault. The Thick Film resistor network RN101 had an out-of-tolerance section (pins 3-5). I found out by exchanging the network for the one in Ch2 and the fault transferred over.
I now just need to make & fit a new ribbon cable to replace the one damaged by a previous engineer.
This was a difficult one. I discovered that the +ODEP voltage was perfect at 12.6V...however I spotted today that the voltage was positive with respect to 0V...it should be negative -12.6V !! So we had a hard odep fault on Ch1.
After 3 long days of testing, swapping chips, testing for leaky capacitors etc., I finally found the fault. The Thick Film resistor network RN101 had an out-of-tolerance section (pins 3-5). I found out by exchanging the network for the one in Ch2 and the fault transferred over.
I now just need to make & fit a new ribbon cable to replace the one damaged by a previous engineer.
