Intermittant loss of bass throughput. Of course not been able to trace .
induce the problem - other than presumed PbF problem.
Owner never uses the monitor output. Main and monitor PA look the same
components but not mirror/same layouts. Any likely problems swapping the
simple screened leads from each preamp section and swapping the PA speaker
output leads?
Will then at least localise the problem to prea , if the problem recurs

On 27/01/2012 14:55, N_Cook wrote:
Intermittant loss of bass throughput. Of course not been able to trace .
induce the problem - other than presumed PbF problem.
Owner never uses the monitor output. Main and monitor PA look the same
components but not mirror/same layouts. Any likely problems swapping the
simple screened leads from each preamp section and swapping the PA speaker
output leads?
Will then at least localise the problem to prea , if the problem recurs


Are you saying that the problem is only on the monitor output?
Doesn't the unit use both power amps in one mode, and one amp for main
speakers and the other amp for foldback speakers in monitor mode?

I would look at where the signal splits to the two separate power amps
and maybe test each power amp module with an external signal source.

Have a look at the slider pots on the graphic equalisers, they sometimes
get damaged in transit.

Ron wrote in message
...
On 27/01/2012 14:55, N_Cook wrote:
Intermittant loss of bass throughput. Of course not been able to trace .
induce the problem - other than presumed PbF problem.
Owner never uses the monitor output. Main and monitor PA look the same
components but not mirror/same layouts. Any likely problems swapping the
simple screened leads from each preamp section and swapping the PA
speaker
output leads?
Will then at least localise the problem to prea , if the problem recurs


Are you saying that the problem is only on the monitor output?
Doesn't the unit use both power amps in one mode, and one amp for main
speakers and the other amp for foldback speakers in monitor mode?

I would look at where the signal splits to the two separate power amps
and maybe test each power amp module with an external signal source.

Have a look at the slider pots on the graphic equalisers, they sometimes
get damaged in transit.

Not a stereo mixer , the main and monitor channels are separated in the
mixer section
Problem comes through to the main amp, maybe in monitor channel as well, but
as owner does not use that and I've not been able to induce the problem I
don't know where the problem lies

I had to get inside the mixer section to replace some worn out XLR (3 years
old). I've never seen this - what happened to inspection satages in
production. ?
A 1N4148 type D in ch7 , D2, the cathode had never been placed through the
pcb let alone soldered. It had its lead bent at placement and ended up
component side , squashed under the metal shroud of the main level pot of
ch7, so grounded, should have gone to pin 9 of an 074.
I doubt it is the tinny-sound problem source though

On 27/01/2012 17:34, N_Cook wrote:
wrote in message
...
On 27/01/2012 14:55, N_Cook wrote:
Intermittant loss of bass throughput. Of course not been able to trace .
induce the problem - other than presumed PbF problem.
Owner never uses the monitor output. Main and monitor PA look the same
components but not mirror/same layouts. Any likely problems swapping the
simple screened leads from each preamp section and swapping the PA
speaker
output leads?
Will then at least localise the problem to prea , if the problem recurs


Are you saying that the problem is only on the monitor output?
Doesn't the unit use both power amps in one mode, and one amp for main
speakers and the other amp for foldback speakers in monitor mode?

I would look at where the signal splits to the two separate power amps
and maybe test each power amp module with an external signal source.

Have a look at the slider pots on the graphic equalisers, they sometimes
get damaged in transit.

Not a stereo mixer , the main and monitor channels are separated in the
mixer section
Problem comes through to the main amp, maybe in monitor channel as well, but
as owner does not use that and I've not been able to induce the problem I
don't know where the problem lies

I had to get inside the mixer section to replace some worn out XLR (3 years
old). I've never seen this - what happened to inspection satages in
production. ?
A 1N4148 type D in ch7 , D2, the cathode had never been placed through the
pcb let alone soldered. It had its lead bent at placement and ended up
component side , squashed under the metal shroud of the main level pot of
ch7, so grounded, should have gone to pin 9 of an 074.
I doubt it is the tinny-sound problem source though


No, it's not a stereo mixer, but you can use both power amps for the
main speakers, one amp for each mains and mons or (I think) you can
use both power amps in bridge mode.

So it should be a simple case of amplifier substitution, you can
probably find an insert jack on the front panel to give you a direct
path to the power amps and a handy listening point for testing the preamps

R

"N_Cook" wrote in message
...
Ron wrote in message
...
On 27/01/2012 14:55, N_Cook wrote:
Intermittant loss of bass throughput. Of course not been able to trace
.
induce the problem - other than presumed PbF problem.
Owner never uses the monitor output. Main and monitor PA look the same
components but not mirror/same layouts. Any likely problems swapping
the
simple screened leads from each preamp section and swapping the PA
speaker
output leads?
Will then at least localise the problem to prea , if the problem recurs


Are you saying that the problem is only on the monitor output?
Doesn't the unit use both power amps in one mode, and one amp for main
speakers and the other amp for foldback speakers in monitor mode?

I would look at where the signal splits to the two separate power amps
and maybe test each power amp module with an external signal source.

Have a look at the slider pots on the graphic equalisers, they sometimes
get damaged in transit.

Not a stereo mixer , the main and monitor channels are separated in the
mixer section
Problem comes through to the main amp, maybe in monitor channel as well,
but
as owner does not use that and I've not been able to induce the problem I
don't know where the problem lies

I had to get inside the mixer section to replace some worn out XLR (3
years
old). I've never seen this - what happened to inspection satages in
production. ?
A 1N4148 type D in ch7 , D2, the cathode had never been placed through the
pcb let alone soldered. It had its lead bent at placement and ended up
component side , squashed under the metal shroud of the main level pot of
ch7, so grounded, should have gone to pin 9 of an 074.
I doubt it is the tinny-sound problem source though





"Tinny sound" is more often than not due to a balanced input signal (e.g. a
microphone) becoming "one legged", or in other words losing one of its two
signal inputs.

Since you have also stated you have had to replace some worn out XLR's, I
would very much suspect this was the source of the problem, which you have
now fixed, hence you not now being able to recreate it.



Cheers,


Gareth.