Avalon U5 need power LED

[pucho812]

Hi! I just wanted to share with you my experience repairing this piece of equipment. From one day to another it stopped working. I am in EU so the mains switch was set at 230V. I switched it to 115V and conected it to a 115V autotransformer and it worked! So I guessed that one of the primary windings was open. Once I put a new transformer, the unit didn't turn on. Well, some audio was passing trough but the power led wasn't lit. So, as Pucho812 said:

That was it. Once I secured the connections, the unit was working again!

View attachment 115468

Nicely done. These units sound so good as a DI it would be a shame to not have them working.

 

[Jules123]

Hello,
Ive got a similar problem, U5 with distorted audio and no power led, switches (were) working.
I checked transformer secondaries which were ok, then I found C11 being open circuit.
Replaced it and when powering on, R50 burnt out... So C11 may not have been the main problem.
Then I removed C11 completely and switched on again, not a good idea, now R84 was burning...
So, can anyone help me out? I also need the values for R50 and R84.
Thanks!

 

[pucho812]

Hello,
Ive got a similar problem, U5 with distorted audio and no power led, switches (were) working.
I checked transformer secondaries which were ok, then I found C11 being open circuit.
Replaced it and when powering on, R50 burnt out... So C11 may not have been the main problem.
Then I removed C11 completely and switched on again, not a good idea, now R84 was burning...
So, can anyone help me out? I also need the values for R50 and R84.
Thanks!

R50 and R84 should be the same value as R51 and R83 which I believe is a 3K32 resistor value.
As the are the same as the others which have not burned out yet, please double check my work.

As for why they are burning up, recap the unit. it will be the 100uF/50V caps. As they are relatively inexpensive, replace all the 100uF and the 10uF lytics. I had many an Avalon resistor burn out when caps had shorted.

If you have any more questions, let me know.
good luck.