Crane Song STC-8 noise and crackling problem

[YannLu]

hi guys,

I have here a very annoying issue with a channel on the Crane Song STC-8 of a customer (I am pro audio tech) :

One channel provides some crackling and noise after a couple hour. it occurs only if the unit is racked because of the high temperature in it.

I have already replaced the 10µ caps and some transistors (MJE172-182 mounted on the radiator).

Notice that I have no schematics to service this...

If someone can help, I will rreally appreciate.

Yann Lu

 

[mjrippe]

Have you tried contacting the company?  I was servicing a Trakker and they sent me schematics and calibration instructions. 

 

[Bo Deadly]

If it's a current product definitely contact the company.

If not, open it up, leave it running and maybe cover it with something to get it warm enough to cause the problem and then .... use one of those air-duster canisters with the long straw attached to the tip to blow cold "air" onto specific parts. Put the straw right up close to the part and give it a little burst and listen carefully for any change.

I found a bad triac in by old B77 R2R that way.

 

[Khron]

Cracked solder joints, wonky silicon?

Replacing all the input PNPs from the mic preamps in my Behringer (i know, i know...) DDX3216 is on my to-do list; a few channels are really noisy and crackly, and that went away when i did that on the noisiest one.