Hi thanks for reading,
My board is a Soundcraft TS-12 and has an issue.
Channel 1 does not cut, when another channel is solo'ed. It should, the other channels 2-24 do.
I have attached a pdf of the schematics.
Here is what I have found;
A jumper 'J1' should be installed to avoid (the optional 'do not cut my fx return' option), J1 is installed and continuity checked.
The schematic of i/o channel (1st page) middle bottom shows the 'Cut' button circuit... I noticed what I guessed to be a DC control voltage enters that circuit via connector 2 pin 19 'the CUT line from Automated L/H i/o' and connects directly to pin 1 of IC 14-A.
1. I tried replacing IC14 (A-D), no change ;(
2. I replace IC12 in the SOLO circuit but this had no change.
3. I measure a DC voltage at Connector 2 pin 19 on the smaller switch pcb (connector 2 is part of a interconnect system between main pcb and smaller switch pcb), I measured both the faulty module and a working module while soloing another track;
I noticed the presence of approx -8.6VDC present whilst un-Cut (no LED active) this signal was interrupted on the working channel when I solo'ed another channel (hence cutting the channel as it should), however the signal WAS NOT interrupted on the faulty channel when I solo'ed another channel! So this is a clue....but I am stuck
This DC voltage on connector 2 pin 19 the ' CUT line from Automated L/H i/o' DC voltage WAS interrupted on the faulty channel when I pressed the CUT button on the faulty channel itself. So is there something stopping the signal from the other channel? What is this something on the other channel? The SOLO circuit...is there a SOLO bus or something that interconnects between channels? Can anyone see it by looking at the schematic?
This is as far as I got. I suspect the Fet's TR5, TR6 in SOLO circuit, they look important and connected to CUT circuit but I am just guessing... I confess, I am at the limit of my knowledge, I did not study logic circuits ( i was too busy building GYRAF kits and recording) and I only know that a FET can be used as a switch...so this is why I suspect the fets, how do I test them? Do I de-solder them? Can I test them in circuit with my multimeter?
Thanks.
My board is a Soundcraft TS-12 and has an issue.
Channel 1 does not cut, when another channel is solo'ed. It should, the other channels 2-24 do.
I have attached a pdf of the schematics.
Here is what I have found;
A jumper 'J1' should be installed to avoid (the optional 'do not cut my fx return' option), J1 is installed and continuity checked.
The schematic of i/o channel (1st page) middle bottom shows the 'Cut' button circuit... I noticed what I guessed to be a DC control voltage enters that circuit via connector 2 pin 19 'the CUT line from Automated L/H i/o' and connects directly to pin 1 of IC 14-A.
1. I tried replacing IC14 (A-D), no change ;(
2. I replace IC12 in the SOLO circuit but this had no change.
3. I measure a DC voltage at Connector 2 pin 19 on the smaller switch pcb (connector 2 is part of a interconnect system between main pcb and smaller switch pcb), I measured both the faulty module and a working module while soloing another track;
I noticed the presence of approx -8.6VDC present whilst un-Cut (no LED active) this signal was interrupted on the working channel when I solo'ed another channel (hence cutting the channel as it should), however the signal WAS NOT interrupted on the faulty channel when I solo'ed another channel! So this is a clue....but I am stuck
This DC voltage on connector 2 pin 19 the ' CUT line from Automated L/H i/o' DC voltage WAS interrupted on the faulty channel when I pressed the CUT button on the faulty channel itself. So is there something stopping the signal from the other channel? What is this something on the other channel? The SOLO circuit...is there a SOLO bus or something that interconnects between channels? Can anyone see it by looking at the schematic?
This is as far as I got. I suspect the Fet's TR5, TR6 in SOLO circuit, they look important and connected to CUT circuit but I am just guessing... I confess, I am at the limit of my knowledge, I did not study logic circuits ( i was too busy building GYRAF kits and recording) and I only know that a FET can be used as a switch...so this is why I suspect the fets, how do I test them? Do I de-solder them? Can I test them in circuit with my multimeter?
Thanks.