Troubleshooting tascam m series headphone pre amp

[elguapo511]

I have a tascam m-106.

When I send any of the 6 input channels to play out of the headphones, the right Channel breaks up and crackles consistently. This also happens when any channel is sent to the Monitor outputs on the rear.

Those are the same pre amp right? The headphone and the monitor?

If they are then is it easier to unscrew it and find the faulty part?

Or, open it and replace the entire pre amp component?

I have a spare 106 with many other issues that I am not using for parts.

So does that preamp in particular come out all at once? Because that seems like an easier fix...

 

[Laszlo]

Hello elguapo511,

in the M-106 the Phone amp is the monitor amp too, so what you hear in the phones is the same as what you get at the MON output jacks. After routing the channel signal respectively, check if the noise is audible in any of the PGM outputs. If yes, then most probably the noise comes from one of the PGM amps, or from earlier stages.
If not, it is most likely due to some mecahnically rooted (contact) issue either on the monitoring section of PSU PCB (The monitor amp circuit actually is located on the PSU PCB, unfortunately) or on the Monitor Select PCB. You can try to deoxit the Monitor selector switch contacts, and, the noise also can be generated by faulty PCB sockets. In the latter case you need to detach the sockets and reattach them after some cleaning, also double check the solder joints. You may try to click the suspected areas with a screwdriver (beware of short circuits), you may find some badly soldered legs of a component.
Regards,
Laszlo

 

[SkywaveTDR]

It seems that you are in good hands so far. The lower mixers made use of a buss bar that has had connection issues. They go along the bottom of the channel PCB's and in a few cases where the ground was not working in one channel I had to run a ground wire from another channel to the broken one to get it to work. I don't know if it was connector or a broken trace or what but that will have to be looked at if you have one of these kinds of constructs.

 

[elguapo511]

I checked every connection I could see, and also de oxt what i could. plugged it in and it is absolutely back to normal. A total mess to take apart and maddening to get all of the sliders back in place.

thanks again for all the tips.

I am about to open my 34 B and if its only the belt it should be in working order.

 

[SkywaveTDR]

OK, The 34B like many 30 series make use of the damping cylinder tension arm mechanism. These are often time these days frozen up. They need to be taken off taken apart and the old grease removed with denatured then once cleaned then I put damping grease into the cylinder to make them do what they are meant to do. Then your tension arms will work right after that.
In changing the belt this also allows one to take the flywheel off the capstan shaft and pull the shaft to oil the capstan bearing with AMSoil synthetic oil that I use that gives far greater results than what was used in the past. This is the correct maintenance of the deck although many people ignore these things and end up with high wow and flutter as well as having the speed in a place that is incorrect. Changing the belt and Lubrication means setting the speed correctly with speed tape and frequency counter or wow and flutter meter. The Motherboards on these models have a history of bad feed-through solder pins. Often times the solder joints have to be resoldered either from the card side or top. I am only reporting what I come across not anything else.

 

[elguapo511]

I opened the 34b. Everything is moving nicely.

I don’t have the amsoil so just left it all intact.

I did remove and clean the flywheel and the other part.

The belt was old and stretched. But still intact.

So a solid cleaning and mild de oxit was all I did.

It is moving and sounding as I think it should.

Next steps are calibrating. I have no tools are measuring tapes to do so.... so I’m on the way to learn all of that. Seems like my decks are mechanically functioning

 

[SkywaveTDR]

Yes, Alignment tapes are needed to do the job as well as a AC millivolt meter and a frequency counter or wow and flutter meter. The basic tools.