tascam 388 doesn't detect tape

  • Thread starter Thread starter suonoacaso
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suonoacaso

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hi everyone, i have purchased for nearly nothing an old Tascam 388. It seems in very good conditions, fuses are ok, belt is fine. Transport section seems dead.
If i load a reel, capstan motor don't move, if i press play, rew, etc. nothing happens.

Any ideas/suggestion?
Thank you!
 
Welcome!

  • What is your experience with repairing electronics?
  • What test equipment do you own?
  • How committed are you to your 388?
  • Do you have the full service manual for the 388?
  • Why?

The first step after verifying the fuses are good and the capstan belt is good is to check and make sure your power supply is working. Reseat the power supply and reel servo PCBs. If that doesn't change anything you need to take the bottom cover off, locating the solder joints for where the power supply board plugs into the MOTHER 2 PCB, and checking voltages of the multiple power rails.

Before that though, you say the fuses seem fine. Did you check for continuity between each fuses' terminals with a multimeter? Fuses can look fine, but need re-seated or a fuse may have just a hairline break in the filament and be no good. Test for continuity.

If the fuses check out good, and the power supply is outputting proper voltages, I would then check the voltage of the +24V transport power supply when you lift the right tension arm.

Does the tape counter display light up when you turn on the machine? Can you get the tape counter to count when you spin the counter roller?

You say the capstan belt is fine. How do you know? What did you do to verify this?
 
thanks for your reply

What is your experience with repairing electronics? pretty basic, but i'm diligent and patient
What test equipment do you own? a good multimeter
How committed are you to your 388? not much. i've got one in good working conditions, and bought this one for nearly nothing (40€)
Do you have the full service manual for the 388? yes

yes, i checked fuses for continuity, with the multimeter.
to verify capstan belt i've removed the bottom panel and moved motor manually a little, capstan moves.....
yes, the counter display lights up......but it doesn't count if i spin the counter roller.

now i'm going to reseat the 2 PCBs you said. in order to do that it's sufficient to pull them up after the removal of the bracket holder?

thank you very much
 
Ok, i've done the pcb reseat....nothing.
Also checked 24v voltage on mother(2)pcb....reads 20.48v no matter If you lift or not the right tension arm. Always read 20.48
I've noticed this: when i turn off the machine, the capstan motor turns a little, before shuttin off....
 
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Did you remove the fuses while checking them?

Does the counter roller need the right-hand tension arm to be lifted before it will count? It might be worth checking the microswitch if you can, since that usually acts as an interlock on the transport system.
Were you saying that the machine wouldn't go into fast wind either?
 
jpmorris said:
Did you remove the fuses while checking them?

Does the counter roller need the right-hand tension arm to be lifted before it will count? It might be worth checking the microswitch if you can, since that usually acts as an interlock on the transport system.
Were you saying that the machine wouldn't go into fast wind either?
Click to expand...


Yes i removed fuses while checking them....
The counter do not count in any cases...and the machine wouldn't go in fast wind either.

Thanks
 
My humble opinion:

It's not likely a simple problem. It sounds like there is a transport logic issue and it may be fairly involved.
 
Don't know if this help: i've accidentally turned on the machine without fuse F4 and both capstan and reels motor started running.
 
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now i've got a strange (to me) problem......i've cleaned and reseated all pcbs on the top of the machine (power supply, reel servo, etc.) and the machine WORKED.
i turned the 388 off and left it off for two days.
today i turned it on and don't work again.
maybe it's just a cleaning/contact issue?
ideas?
 
Hopefully. Otherwise it might be a cold solder joint or something similar. I have heard tales of woe about the wave soldering on some Tascam machines, and of technicians who reflow all the solder as a matter of course. If cleaning the contacts doesn't help, it might be an issue with the PCB soldering.
 
That's a good suggestion ^^^^^

The place where the solder joints can fail is where the connector of the plug-in board is soldered to the board. I would re-flow the solder joints for the power supply PCB and the reel servo PCB. Those are the only two plug-in boards that would effect the kind of symptoms you describe.
 
So i've re-flowed all solder joints on power supply and reel servo pcb's.
Also i've done this work on mother 2 pcb, where the supply and reel servo
Pcb's joints.
Nothing.....
Other suggestions?
Thanks
 
sweetbeats said:
What do you mean by "nothing"?
Click to expand...

I mean: transport is dead again.
Capstan doesn't turn
Reels motors doesn't turn.
Counter doesn't count.

I've also cleaned/reseated all connectors
on the control pcb and mecha joint pcb.

The thing that i can't understand is that
everything worked perfecty for about a day
Then i turned off the machine, left it off for
two days, without moving or touching
nothing, and when i turned it on again, transport
was dead again.....

Thanks
 
Solved, maybe.
it was the right tape sensor.
i don't know if it was some sort of contact or a matter of aligment between the led and the phototransistor.
i noticed when i was loading a tape, that the capstan turned a little for a second or less, so i started playing around the right tension arm and the sensor bracket...i pulled and bended a little the metal bracket that holds the phototransistor and bingo!
transport worked again.
i've bended a little the bracket in the opposite direction (down) and trasport stopped working again.
i've restored the bracket and worked again.
 
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