Tascam 34 flywheel noise/capstan motor noise + tracks not working

[artr]

I inspected the wiring from the heads, and found the reason for track 4 being gone on the SYNC head...
that little bugger must have broken off when I had the assembly out. I soldered it back on, and now all tracks are working on the SYNC/record head! Records and plays on all tracks. But still no track 1 on the playback head.

Well just make sure you look at the heads under good light and with magnification if necessary. Put up a pic of the heads if you can.

Somebody else more familiar with the 30 series will need to chime in, but I know other period models of Tascam machines had muting relays mounted external to the amp cards, like on the motherboard. If those go bad that can cause signal issues, but that wouldn’t be specific to individual tracks on the heads, the relays cut the signal to the outputs when powering up to avoid the thump at the outputs.

When you say no repro on 1, does that mean no signal from the sync or repro heads? And you are using a known hood recording with signal on all 4 tracks?

Sorry, it was a bit unclear - I meant no signal on track 1 on the playback/repro head specifically. And yes, I´m using a recording with all 4 tracks recorded. I cleaned the heads as well as I could with isopropyl:
and yea, still no track 1 on the repro head. There´s a bit of a blemish on the upper right corner of it, I don´t know whether it´s a scratch or some gunk, but I couldn´t get it off. It seems like it´s not in the tape path though. Would you say this is clean enough?
I´ve read that the solder joints can be bad on these machines, and that resoldering the connections on the motherboard could be a solution to a problem like this. I´m ok with a soldering iron, so I could do this - but is the motherboard the PCB that the amp cards are plugged into, or the big PCB board that´s positioned vertically on the back of the machine?

 

[sweetbeats]

A motherboard is a PCB to which other boards or peripherals are connected/plugged in, so the motherboard is the one into which the amp cards plug in.

If it was me I’d take my test tape, reproduce the 1kHz tone and probe with my scope to the first point off track 1 of the repro head I could access to check to see if the tone is coming off the head. I don’t have a model 34 service manual so I can’t give any specific advice where that point is.

Can you shine some light on the face of the repro head and post another pic of just the repro head with light on it, positioning your camera to avoid reflections as much as possible? I’m trying to see the coil gap.

By the way nice job resolving the sync head issue. Thumbs up.

 

[RRuskin]

Should you not be able to fix the repro head problem, you still have a viable working machine. The repro head is there primarily for ease of alignment. Once done, all work is supposed to done off the record/sync head. Its playback response is the same as the the repro head.

 

[artr]

A motherboard is a PCB to which other boards or peripherals are connected/plugged in, so the motherboard is the one into which the amp cards plug in.

If it was me I’d take my test tape, reproduce the 1kHz tone and probe with my scope to the first point off track 1 of the repro head I could access to check to see if the tone is coming off the head. I don’t have a model 34 service manual so I can’t give any specific advice where that point is.

Can you shine some light on the face of the repro head and post another pic of just the repro head with light on it, positioning your camera to avoid reflections as much as possible? I’m trying to see the coil gap.

By the way nice job resolving the sync head issue. Thumbs up.

Thanks sweetbeats! I don´t have a scope yet, but I was thinking what else I could do that follows that logic - the wiring from the head goes into the motherboard (thanks for clearing it up btw) with a little plastic connector thing for each track, that you can take off. So I swapped track 1 and 2 on the motherboard, so track 1 on the head was going through the track 2 electronics - and it was playing what I had recorded on track 1 on the tape just fine. So the head is all good! And we´ve also ruled out the amp cards, so I guess that leaves the motherboard?

Should you not be able to fix the repro head problem, you still have a viable working machine. The repro head is there primarily for ease of alignment. Once done, all work is supposed to done off the record/sync head. Its playback response is the same as the the repro head.

Ah I see, I thought that the sync head was somehow worse for playback. That´s good to know though - I already started recording stuff, and it does sound good coming off the sync head. I would love to fix the repro head though. Is there any difference at all between the heads then, like could you swap them? Not that I would for this problem, just curious

 

[RRuskin]

Ah I see, I thought that the sync head was somehow worse for playback. That´s good to know though - I already started recording stuff, and it does sound good coming off the sync head. I would love to fix the repro head though. Is there any difference at all between the heads then, like could you swap them? Not that I would for this problem, just curious

I was told by a TASCAM tech that the repro heads on all of their multitrack machines made after the 70 series were in fact, R/P heads that didn't meet spec on the record side of things. With this info, I wouldn't swap heads unless it was the only way to get a machine up and & running again.

 

[sweetbeats]

I was told by a TASCAM tech that the repro heads on all of their multitrack machines made after the 70 series were in fact, R/P heads that didn't meet spec on the record side of things. With this info, I wouldn't swap heads unless it was the only way to get a machine up and & running again.

That’s super interesting. Makes sense though if it’s true. You know the same sort of thing happens with higher spec capacitors for instance. For instance the parts that are within 5% tolerance are sold as 5%…10% sold as 10%, etc. Same part, they just get measured and sorted.

 

[sweetbeats]

Thanks sweetbeats! I don´t have a scope yet, but I was thinking what else I could do that follows that logic - the wiring from the head goes into the motherboard (thanks for clearing it up btw) with a little plastic connector thing for each track, that you can take off. So I swapped track 1 and 2 on the motherboard, so track 1 on the head was going through the track 2 electronics - and it was playing what I had recorded on track 1 on the tape just fine. So the head is all good! And we´ve also ruled out the amp cards, so I guess that leaves the motherboard?

Ah I see, I thought that the sync head was somehow worse for playback. That´s good to know though - I already started recording stuff, and it does sound good coming off the sync head. I would love to fix the repro head though. Is there any difference at all between the heads then, like could you swap them? Not that I would for this problem, just curious

Good thinking on the connection swap. So you really need to have a set of schematics at this point and identify what is between the amp card and the head connector and start tracing it out. I’d help if I had the schematics but I don’t. I’m sure there are similarities with the 32 and the 38, for which I have service manuals, but I’m sure there are plenty of differences too and I can’t afford to go on a fishing expedition time-wise.

Used to be record/sync heads had a different reproduce spec than the repro heads on a three-head machine. The head performance is a product of many things including the coil gap, and in the ideal world that gap is different between the recording process and the reproduce process, but head technology improved to the point one size fit all and that’s when we saw the advent of sync heads with the same reproduce specs as the repro head, because they were the same part…better manufacturing tolerances, thinner laminations, etc. The 70 series machines were old school with different gaps between the record and reproduce heads, but with the 80-8 that changed…same specs, same head. Not sure about the 90-16. The 85-16 though had the same heads for record and reproduce and everything thereafter.

 

[RRuskin]

Used to be record/sync heads had a different reproduce spec than the repro heads on a three-head machine. The head performance is a product of many things including the coil gap, and in the ideal world that gap is different between the recording process and the reproduce process, but head technology improved to the point one size fit all and that’s when we saw the advent of sync heads with the same reproduce specs as the repro head, because they were the same part…better manufacturing tolerances, thinner laminations, etc. The 70 series machines were old school with different gaps between the record and reproduce heads, but with the 80-8 that changed…same specs, same head. Not sure about the 90-16. The 85-16 though had the same heads for record and reproduce and everything thereafter.

The 90-16 repro and R/P heads were identical with regard to playback specs.

 

[artr]

Thanks so much for the great replies and help guys! I appreciate it a lot. I think I´ll take a break for a week or so, and just enjoy recording using the SYNC head for playback, I´ve had the thing for 3 weeks and hardly recorded anything. Then I´ll touch up the soldering on the motherboard, as it seems to be a common problem on these, and it also seems to be likely after excluding the head and amp cards. If that doesn´t help, I´ll follow your advice sweetbeats, and get a proper manual and trace it. I have downloaded a couple of different ones, and they all seem to be either incomplete or blurry. I have one with the schematics, but you can hardly tell what it says. Any recommendations on where to get a good quality PDF manual?

 

[sweetbeats]

I would start my contacting Tascam Parts and asking if they have a service manual. They might have a high quality reprint, and likely cheaper than online. If not there is check servicemanuals.net

Yours is the “34” and not the “34B”, correct?

 

[artr]

I would start my contacting Tascam Parts and asking if they have a service manual. They might have a high quality reprint, and likely cheaper than online. If not there is check servicemanuals.net

Yours is the “34” and not the “34B”, correct?

Just sent them a mail. Yes correct!

 

[TheSynthDev]

It sounds like you might have a problem with the flywheel or capstan motor. I would recommend taking it to a technician to have it looked at.

--
Jason Hook. I enjoy remixing old songs using Audacity together with UnMixIt for vocal removal or isolation

 

[artr]

It sounds like you might have a problem with the flywheel or capstan motor. I would recommend taking it to a technician to have it looked at.

--
Jason Hook. I enjoy remixing old songs using Audacity together with UnMixIt for vocal removal or isolation

Jason if you´re referring to the first post, I fixed the flywheel, at least it´s not knocking anymore

 

[sweetbeats]

Just sent them a mail. Yes correct!

I really would recommend calling. It may take some time before you get a response to the email. If at all. At least that’s the way things were for a long time…not sure if it remains that way. I *always* call.

 

[artr]

I really would recommend calling. It may take some time before you get a response to the email. If at all. At least that’s the way things were for a long time…not sure if it remains that way. I *always* call.

Thing is, there is no Tascam here in Denmark, so I´d have to call them in Germany or France. Which I could, but it´s pretty expensive. So I´ll wait for a few days, if I don´t get an answer, I´ll call. Thanks for the heads up!

 

[sweetbeats]

I had no way to know where you were in the world.