Focusrite pre-pack isa428 problem
 

Hi all,
Recently I got this machine into my shop. It's a focusrite pre amp,
high performance studio quality machine. The thing is an intermittent
failure on channel 1. When MIC is selected as input, the signal may
suddenly disappear. The problems only exist when MIC is selected. This
often happens after a couple of hours of operation, so the problem
seems to be heat dependent. Also, when selecting another input and
again select MIC, the signal is most often coming back. But of course
disappear again after a while. I wonder if anyone of you have any
valueable tips what could be the problem. Solderjoints are checked. The
machine uses low-power relays for audiosignal switching and I may think
a relay is causing the problem. Any help is appreciated,
Regards
Stefan

Focusrite pre-pack isa428 problem
 

On 22 Jul 2006 08:06:06 -0700, put
finger to keyboard and composed:

Hi all,
Recently I got this machine into my shop. It's a focusrite pre amp,
high performance studio quality machine. The thing is an intermittent
failure on channel 1. When MIC is selected as input, the signal may
suddenly disappear. The problems only exist when MIC is selected. This
often happens after a couple of hours of operation, so the problem
seems to be heat dependent. Also, when selecting another input and
again select MIC, the signal is most often coming back. But of course
disappear again after a while. I wonder if anyone of you have any
valueable tips what could be the problem. Solderjoints are checked. The
machine uses low-power relays for audiosignal switching and I may think
a relay is causing the problem. Any help is appreciated,
Regards
Stefan

Can you bridge the relay contacts when the problem occurs?

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Focusrite pre-pack isa428 problem
 

Franc Zabkar skrev:

On 22 Jul 2006 08:06:06 -0700, put
finger to keyboard and composed:

Hi all,
Recently I got this machine into my shop. It's a focusrite pre amp,
high performance studio quality machine. The thing is an intermittent
failure on channel 1. When MIC is selected as input, the signal may
suddenly disappear. The problems only exist when MIC is selected. This
often happens after a couple of hours of operation, so the problem
seems to be heat dependent. Also, when selecting another input and
again select MIC, the signal is most often coming back. But of course
disappear again after a while. I wonder if anyone of you have any
valueable tips what could be the problem. Solderjoints are checked. The
machine uses low-power relays for audiosignal switching and I may think
a relay is causing the problem. Any help is appreciated,
Regards
Stefan

Can you bridge the relay contacts when the problem occurs?

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.



The thing is, I don't have access to the bottom side during operation
of the unit. I don't have access to any schematics so rather "direct"
hints are necessary unfortunately.