crest 8001 no sound problem

Archived from groups: rec.audio.pro (More info?)

Hi all,

Has anyone worked on these amps ? I've replaced the output stage which had
the usual blown stuff, and now both modules work fine, BUT, there seems to
be some problem with the chan A on the colume PCB.. Can't find a thing
wrong with it, but there is no sound output at all on Chan A..... ive swaped
the 2 output modules over and they both work fine on Chan B, but nothing
works on Chan A so theres only the volume PCB left!

This board seems to have a lot of stuff on it to the one in the diagrams I
have which is a little odd, maybe its a really old version of something ?
In anycase can anyone shed any light on what could be the problem ?

Cheers,
Chris

Archived from groups: rec.audio.pro (More info?)

"nmm" <voxman@arvotek.net> wrote in message
news:1118189764.610123.74010@g43g2000cwa.googlegroups.com...
>
>
> exxos wrote:
>> Hi all,
>>
>> Has anyone worked on these amps ? I've replaced the output stage which
>> had
>> the usual blown stuff, and now both modules work fine, BUT, there seems
>> to
>> be some problem with the chan A on the colume PCB.. Can't find a thing
>> wrong with it, but there is no sound output at all on Chan A..... ive
>> swaped
>> the 2 output modules over and they both work fine on Chan B, but nothing
>> works on Chan A so theres only the volume PCB left!
>>
>> This board seems to have a lot of stuff on it to the one in the diagrams
>> I
>> have which is a little odd, maybe its a really old version of something ?
>> In anycase can anyone shed any light on what could be the problem ?
>>
>> Cheers,
>> Chris
>
>
> Did you trace out the "Mono-Dual-Bridge" switch? might be a short
> somwhere along that circuit.
>

I've not checked the switch, though I would think that I would still get a
output from the speaker ?





> Usually the diode sensor for thermal shutdown is the thing that screws
> up and turns the 8001 off. They can get dusty.
>

I had to replace 2 diodes which I assume are the sensor, though the module
is not the problem, both module work in the chan A wiring.



> Re post in alt.audio.pro.live-sound there are some folks there that
> know this stuff.
>

thanks, will give them a try!

Chris