TASCAM 388 Channel not working...

[Tronic Blanc]

Hi guys...I'm a long-time 388 user, but never bothered to open it up until recently. I've had this thing a few years, and channel 3 has always been dead on the mixer. Always seems like the XLR pre and line-ins don't work on channel 3. Just really really faint sound when jacked up all the way.

I just opened the top panel a couple days ago and carefully pulled and re-seated the 6 channel cards in the top panel (left side - above mixer). I didn't touch the cards on the right, or those deep seated cards in the top card bay that are sitting down deep behind the VUs.

Anyway, it's nice to have them re-seated, but channel 3 is still dead. I tested some old tape a long long time ago and from what I remember the tapes with channel 3 content DID play, so it's probably just the mixer section you think? What other troubleshooting tips do yall have for me here? I want to take off the back panel because my tape counter is not working either, and I really want to clean and re-seat the channel cards too. Check all connections etc. I want this thing working right. I am honestly kinda afraid to take the channel cards out. Is that a big deal? Taking off that weird buss bar that straps across them? Man. I'm a newbie at this but I've been reading carefully all the great threads on here showing details and great step by step pics. But yeah, where do you think this channel three diagnosis is at? I wanna make sure while I'm in there that I pull and check everything applicable.

Thanks.

 

[j.harv]

As long as you're very careful, removing the channel cards shouldn't be a problem. You just have to very gently work each connection loose on the long pcb, one at a time. I was a little hesitant when I first did that. But now I have done it a few times with no problems. just take your time.
As for channel 3 not passing audio....The channel card would be a good start. Check all the solder joints for any bad ones. I found a small crack on a solder joint on the trim pot a the top of the card once that was affecting the signal. I reflowed that and it cleared up the problem.
I love poking around in the 388. I always find it interesting to see all the inner workings. And solving problems is always gratifying. Just look over everything closely. Use a flashlight on the pcb's and look for bad joints, bad caps and resistors.
Have fun.