Tascam 48: Unresponsive channel, doesn't follow card

  • Thread starter Thread starter lo.fi.love
  • Start date Start date
lo.fi.love

lo.fi.love

Functionally obsessed.
Hey folks,

Another strange thing happened!

I'm getting some, but almost no input signal on channel 3 of my Tascam 48. On input monitoring I see the VU needle move just slightly, and it moves even less when I monitor in repro while recording a signal.

I've removed that card and swapped it with another, and the issue didn't follow the card. It's always channel 3, regardless of which card I put in slot 3.

It's not my cabling, or the dbx unit, either, as proven by swapping the inputs on the back of the deck.

I don't know if it will play back a track on channel 3, but I will try this.

I'm unable to figure out why this is happening. Before I dig deeper, does anyone have a guess as to how this happened?

Thanks,
Jeff
 
If swapping the card doesn't change anything then the problem lays somewhere between where the signal enters the machine and the card itself, as you said this shows up even trying to monitor input.

I don't have the service manual for the 48 but looking at it to see what paths the signal has to go through to get to the channel card would give you your best clues for items to check.

Wish I could offer more.

Cheers! :)
 
Jeff, is this the case with both the unbalanced and balanced inputs?
 
I'll check that out, thanks for the suggestion!

I've got Thursday and Friday off this week, so I've got a whole four-day weekend to work this out :)
 
I haven't had the time to follow up on this issue (and using only 7 tracks hasn't really gotten in the way), but I did find something interesting tonight. I can playback on channel 3 with the sync head, but not the repro head.

Again, this doesn't follow the cards when I switch them around.

I'm going to look into this more, sometime, but I'm wondering if anyone here wants to venture a guess. Anyone? :)
 
So look very closely at the wiring off the "repro" head.

Possible it was brittle and came off/loose?

Maybe check inputs from the repro head to their point of attachment.

Do you have a Deoxit pen (D100P)?
 
GCalo said:
So look very closely at the wiring off the "repro" head.

Possible it was brittle and came off/loose?

Maybe check inputs from the repro head to their point of attachment.

Do you have a Deoxit pen (D100P)?
Click to expand...

You know, I thought maybe it was something like this, but it didn't seem logical to me. I'm going to try this anyway, checking for continuity through the path beginning at the head's wiring harness.

I don't have a deoxit pen, but I have the spray-can and I'll swab the connector with a Q-Tip.
 
These irritants are the reason why I am going to rebuild the whole machine so they don't pop up intermittently.

I have found that some of the cabling is a bit brittle, and I have noticed the audio card connectors all need cleaning w/Deoxit.

MCM has all the Deoxit and for less than most others.
 
You know what, on second thought...

I really ought to take a look at the *slot* for card three. There might be something wrong with the pins, either a bent pin (I hope not) or a corroded contact.

Why didn't I think of that sooner?

Looks like I'll be on my back with a flashlight for some part of the day...
 
That could be or the pin pushed through the holder! That can happen.

You should have a rotating rack for that 48.
 
And don't forget to check for cracks in the solder around the pin. I've seen a 38 motherboard that had at least 10 cold solder joints like this. Sometimes hard to see (most times....) but easy to reflow with a touch of solder.

-Ethan
 
That's great suggestion as well.

Better give up hopes of being outside for a while, Jeff!
 
GCalo said:
You should have a rotating rack for that 48.
Click to expand...

Want to give me one? My birthday was last week :) heh.

I'm really in for some time inside, like you said. I don't have a rotating rack but I do have a deliciously-overbuilt desk/workbench. I'm gonna have to call a neighbor over to help me move the deck, but ain't so bad.
 
Hey, would you be interested in a 26U rack on casters? I have one I need to sell.

I also have a 16U SKB shock-mounted road rack.

Take a look at my "studio" picture - the 26U rack I'm selling is identical to the one pictured (I have two).
 
my_studio.jpg


There she is, on the right :)

This rack is unique in that all sides have tapped screwholes. Notice I've got a 34B mounted "on its back" on the very top of the rack. I also have a couple of 1U "Filler" panels screwed on the back of the rack to support the snakes coming into the patchbay. On the bottom, I have a 2U filler panel, which supports my power strip.

Darned useful.
 
Well why are you wanting to sell that if you need a rack for the 48!

I need two more of the Tascam tilt racks.
 
I saw it.

Your mother would be after you for sure to clean up that room!!!

Are all those patch bays the reason SF residents are having phone probs this AM?
 
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