Hello
Unit worked until passed voltage to mic handle in channel 2 then no signal would pass thru channels 2 to 8 to monitors or headphones. Problem is hardware as no compu is connected. No schematic available from Tascam. Unit is outside of USA repair by Authorized dealer is automatically replacing the entire board. Price equal to new unit. Any suggestions?
Unit worked until passed voltage to mic handle in channel 2 then no signal would pass thru channels 2 to 8 to monitors or headphones. Problem is hardware as no compu is connected. No schematic available from Tascam. Unit is outside of USA repair by Authorized dealer is automatically replacing the entire board. Price equal to new unit. Any suggestions?
Off hand, a couple of ways occur to me for routing input channels to outputs. Either analog routing using analog switches, or digital routing. If the latter then digital audio could be routed through discrete logic, or else maybe through a programmable chip such as a CPLD or FPGA. If they used a programmable chip and it goes bad then you would need the firmware file to load into a replacement chip.
So, basically you can try looking at the board and see if you can figure out what chips are being used to do what. You might be able to follow some PCB traces around to find out how devices are connected to each other, but that can get tricky when multilayer PCBs are used.
So, basically you can try looking at the board and see if you can figure out what chips are being used to do what. You might be able to follow some PCB traces around to find out how devices are connected to each other, but that can get tricky when multilayer PCBs are used.
Apreciate the input. Obtained schematic for the 4x4 model. Don't have the equipment to work with SMC. Will try to refer out to capable local repair center.
A few years ago I had the opportunity to get to know this interface.
I don't remember what the pass through circuit was like, but...
it uses these two 4-channel ADCs, as they don't work as standalone, so it's probably the main processor that controls it.
You can check if the adc controlling the problem channels is good.
Otherwise... good luck!
I don't remember what the pass through circuit was like, but...
it uses these two 4-channel ADCs, as they don't work as standalone, so it's probably the main processor that controls it.
You can check if the adc controlling the problem channels is good.
Otherwise... good luck!
