688 meter bridge

[Warbirds]

Noticed that my 688 meter bridge does not have the same sensitivity response that it use to have. Meaning levels are always in the red and or barely in the green when recording. Also when I would turn off unit before the meters would show a nice cascading fall effect. No they just plummet from red. Tried adjusting the pots in the back of meter (cover off) with no luck. Any ideas?
Thanks

 

[SkywaveTDR]

Most likely a ground pin is broken at power supply or in meter section. These boards are not soldered to aerospace or NASA level of soldering and I find solder joint on a daily basis where they are broken, ready to break or just ridiculous to leave them the way they are. I resolder many boards taking dull solder lacking joints to those where the joint will never break even if taken on the space shuttle. There are no easy answers and many of these units mixers and deck need to be gone over by a good Technician.

 

[Warbirds]

Thanks Skywave!. She still sounds super nice and records great just the meters are not as sensitive as they use to be..like me Where would be a good starting point? Have had unit apart many time replacing different components (gears, motors, belts, ex) so not afraid to "dig in". Everything looks good on the circuit board meter up top. Also have schematic and service manual for it. Maybe it because I am using only the line in input as I record from my DAW into it???

 

[Warbirds]

I know without the proper test tools this is a shot in the dark