[SOLVED] Main mix very quiet, master vol does not work

Hi, I have been trying to figure out two problems in my master section:

- the sound is very quiet, much lower than the individual outs
- turning the master volume pot makes very difference to the sound level. I can not turn the sound completely down to silence

I am not sure if this is one problem or two. I have been trying to read the schematic from the service manual but I have had no luck. I also read through viewtopic.php?f=24&t=850 but I am not sure if any of it applies to me. I suppose I could try disabling the muting circuit to see if my sound is somehow half-muted?

I tried swapping the op-amp of the master section with one from elsewhere in the Nava. No change.

I also looked for data in the service manual on how loud the master signal is supposed to be; I did not find anything.

check voltage first
check that pot has correct resistant
check 2878s
Are you sure there is any short made?

Thanks!

I already checked the resistance of the pot; looks OK (50k on both tracks).

Which voltage are you referring to: op-amp? Will check that again.

How do I check the 2878 transistors; do I have to unsolder them to check them?

I double-checked the power on the op-amp, it is OK.

I desoldered the 2878 transistors, no change.

jvq wrote:I double-checked the power on the op-amp, it is OK.

I desoldered the 2878 transistors, no change.

Did you check the connection order of the cabling between master section and IO-board (J14-J6)? Maybe you mixed something up here...

http://e-licktronic.com/forum/viewtopic ... 7&start=10

Thanks Klanggenerator, that was it! I had crossed the in/out cables and probably did funky things with the order too. I am surprised there was any sound at all.

Now the the master output is load and the volume knob works.