Noisy 82E10 transformer amp cards --SOLVED--

[oyanliz]

Hi all,

I have some noisy 82E10 amp cards. I have been able to repair 2 of them, desoldering and cleaning the surround areas of the old yellow liquing capacitors. I have other cards that I am not able to find the faulty component.

The cards are recapped and rechipped. I have replaced all the J112 transistors and checked all resistors surround liquing capacitors.

Those amp cards work fine, mic gain with phantom, line input, line trim... all works fine, but the noise is there all the time, when the console is in record mode, in mix mode... The channel must be muted for deleting the noise from the mixing or recording process.

I have attached a mp3 file of the noise of those amp cards and an amp card pictures as well.

Any idea about where to start from... will be very welcome.

Thanks in advance.

Oihan

[amillar]

It's the 5534s (probably just one). You can swap them with a good card to find which it is, or just replace them all if you're feeling keen and rich!

Cheers,

Andy

[amillar]

I should have added - even though you have had the cards rechipped, some 5534s are just noisy from day one. When we built 4ks we always had to check for noise and replace a few on the input cards and sometimes the EQ cards.

Cheers,

Andy

[oyanliz]

Sorry for the late answer. I replaced the 5534 ICs of the noisy input cards and the noise issue was fixed. I did this some months ago.

Thank you so mutch Andy!

Regards.

Oihan