Hello mates, I've been out of the forum along this year, but now I'm back again, adding some new creatures to my bbx zoo hehe, one of them is a Crown CSC850. It is in an overall good condition, well taken care of considering it's near 30 year old.
The problem: it makes a loud sound in left channel, even with volume at zero, some kind of PRRRRRRR very loud, the other channel sounds good, I can tune radio and play tapes.
I thought it was a blown amplifier IC AN7145M, so I bought a new one and installed it but it still makes the same noise, checked most capacitors on the route to the speakers and they seem to be OK. There's 3 more IC´s on the board, one labeled TA7312P and two other labeled LA3160, could any of them be culprit for the annoying noise? Does anybody have a clue on how to troubleshoot this problem? Thanks in advance. Julian.

Hi Julian,i had the same problem on one of my 850's,it turned out to be a bad earth on the playback head,i resoldered it and all was good.

hi julian it could be a bad ground i had a hitachi that had a simular problem and it turned out to be ground related,,if you checked the caps and everything else try locating the grounds and see if they are loose

quote:

Originally posted by chancenellie:
Hi Julian,i had the same problem on one of my 850's,it turned out to be a bad earth on the playback head,i resoldered it and all was good.

Thank you chancenellie, but it does the same noise on radio, tape and aux, so I thin I has nothing to do with cassette heads
Also the noise is constantly loud, regardless of the position of the volume knob.
Regards,
Julian

quote:

Originally posted by ramon:
hi julian it could be a bad ground i had a hitachi that had a simular problem and it turned out to be ground related,,if you checked the caps and everything else try locating the grounds and see if they are loose

Thank you ramon, will check out the grounds and also the record switch on the board, somebody told me that a defective or dirty record switch could be also the problem.
Regards,
Julian

no problem my friend hope you find what it is