Tascam Porta One

[Brad1]

Anyone have a PDF service manual for my old Porta One? I use it for my "couchside idea" recorder, with my old Harmony (with Dean Markley PU) plugged into it. "Hmmm...that's an interesting chord progression...hit power switch, hit 'record'."

Then, I'll monitor that track, and try to work out and record a lead part....before I go through the trouble of setting up all that computer stuff.

The thing seems like maybe the motor is either getting weak, or not getting enough juice. It'll go FF or Rew, but when I hit Play or Rec, the heads go in, and it stops. The main belt seems OK, and I've even torn the transport completely apart and cleaned and lubed the gears, etc. When it sticks, I can turn the big idler, and it'll finish going through its mechanical function to start playing. it's almost like it just doesn't have enough 'oomph' left to get it past it's gear change.

Wondering if a service manual would have voltage check points/adjustments for the transport? I suppose the motor could just be getting weak. I even tried setting the pitch control to full fast to see if a faster speed would spin the mechanism all the way around, but maybe it just doesn't have enough torque?

I'd hate to trash it, it's so handy and I have a couple dozen brand new Maxell tapes left. Otherwise, it still sounds fine, for my purposes. If I was employed, I'd just say heck with and buy a new $200 digital sketchpad.

Anyway, sure would be handy to fix, and I'd be grateful to anyone who has a service manual to send. I have a bunch of snippets on a bunch of tapes that I refer to, and can create a bunch more as I continue to learn more to improve my creativity and get me out my old rut during these idle times.

Thanks,

Brad1

[g1]

That gear was a very common problem in those units. It would wear to a point that the motor couldn't make the heads engage anymore. If it were a motor problem you should have some speed issues.

[Enzo]

Look at the motor spindle closely. WHen it stalls, is the motor shaft still spinning?

The first three things I'd suspect would be rubber, rubber, rubber. Belt may look OK, but does it still have enough grip? Or can it slip? Pulling the head assembly up is the hardest thing that motor is asked to do.

Also, sometimes a bit of grit gets in the gears, and jams them up. Giving the flywheel a turn pushes past the tiny obstruction.

I doubt you have an electrical problem.

[Brad1]

Look at the motor spindle closely. WHen it stalls, is the motor shaft still spinning?

The first three things I'd suspect would be rubber, rubber, rubber. Belt may look OK, but does it still have enough grip? Or can it slip? Pulling the head assembly up is the hardest thing that motor is asked to do.

Also, sometimes a bit of grit gets in the gears, and jams them up. Giving the flywheel a turn pushes past the tiny obstruction.

I doubt you have an electrical problem.

The motor stops turning, and the belt is not slipping. The gears APPEAR to be in good shape. Actually, it seems the larger gear (to the left) is getting a bind right at the end of its travel to click on. It binds whether that little lever is engaged, or not. With just a little nudge on the big idler wheel, it pops past and starts running. I cleaned all the gears, and slopped a little white lithium grease on them, trying to get it into the sliding areas.

With unit off: (Sorry about the fuzzy pics from the sucky camera)


After "Play" is pushed, it gets "sticky" right here:


So, I guess I'll dig around under there to see why it's getting tight. I was just wondering if it's supposed to be that tight, and the motor always just bulled it past, which is why I wondered about the motor getting weak.

Thanks,

Brad1

[g1]

Also make sure it's not the slider plate of the head assy. that's binding.

[Enzo]

Then we start to syspect the motor. Usually the motor is strong enough to slip the belt when the mech stalls. Verify the motor voltage is not collapsing - probably it is OK.

Get a drop of very light machine oil on the motor bushings, might free it up some. Keep oil off the belt and pulleys.

And if nothing helps, I'd be thinking new motor.

Places like MCM used to sell motors, but probably no longer. I have a dead Porta One here, that the motor should be good on. I won;t be repairing the machine, so...

[Brad1]

As usual, Enzo is probably right, and it's probably the simplest thing.

Though the belt didn't appear to be slipping, and the motor stopped when the gears hit the "tight spot", I guess it's possible that it wasn't observable that the belt may indeed have slipped just a tiny bit on either the capstan, the idler, or both...just enough to not pull it completely through its change, but still gripping enough to stop the motor.

Why do I think so? I put relatively tight 1/8" wide rubber band on there...and it takes it right on through. Of course, the rubber band stretched just enough to narrow its width that it doesn't ride properly in the capstan groove's curved surface, but I think it shows that the motor has plenty of power, and it's probably the belt is worn just enough to fool me.

The irritating thing is that the belt WAS the first thing I suspected. As usual, I may have overanalyzed it.

Tascam has those belts for about $5.50 plus shipping, so I think I'll just order one. Actually, their parts are not that unreasonable, and I'm surprised they still have them for that old of a unit. The service manual would be $12.00, and the motor is about $22.00.

As always, thanks Enzo. Oh...and the motor did seem to run a bit more smoothly by squirting a bit of oil into the shaft. If nothing else, it's cleaned up and should work a while longer. Guess if I get it running, I should take all those old tapes of various stages of multitracked songs, ideas, and band recordings and run through them to dump anything interesting into my computer before I have no way to access any of it, huh?

Brad1

Update: As an experiment, out of curiosity, I had some of this stuff lying around:

http://www.plastidip.com/home_solutions/Plasti_Dip

"Hmmm..?" I wondered. Yep, I sprayed a liberal coating on the old belt, and let it dry. Reinstalled the belt, and works like new. I was worried about it flaking off, but it seems fine. Will use this as a short term fix until the new belt arrives.

Just an accidentally found tip that may be useful, for ya'all.

Brad1

[Pablobrad]

I have the manual

Hi Brad1, I have the manual as a PDF if you'd like it emailed?
pablox43@hotmail.com

[Brad1]

Update: (Stumbled onto this, again, and just in case anyone else has one of these old dinosaurs to try to save):

There's a Control PCB Assembly in there that has a transistor (Q1) on it that activates and holds the running state. Mine was "open" when measured, so it was bad. Replaced that, and C1, C2, C3, C4, R3 and R4 (which are all connected directly), and it works fine. (Just replaced all the other stuff because they were cheap, Mouser had them, and why not put new parts in there? Less than $10, shipping included).

Mouser part #s:
Q1: 863-2SD1207S-AE $0.72
R3: 588-OD152JE 1/4watt 1.5K 5% Carbon Comp $0.42
R4: 588-OD333JE 1/4watt 33K 5% Carbon Comp $0.42
C1: 647-UVZ1C101MDD (Nichicon) Aluminum Electrolytic Capacitors 16V,100uF $0.18
C2,C3: 647-UHM1C471MPD (Nichicon) Aluminum Electrolytic Capacitors 16V,470uF 20% $0.44 (x2= $0.88)
Total $2.62 + ~ $5.00 S/H, "Economy" shipped. (Actually, this is what it WOULD be, if I hadn't ordered about 80 other small items...still about $5.00 S/H).

The board is attached to the transport, and the entire transport must be removed to get to the underside of the board. It's the small board behind the transport. Not difficult to do, just need long, skinny Phillips screwdriver to get to some of the transport screws, and it will lift out. (Make sure no tape is in there). What I figured happened was that some of the caps/resistors drifted out of tolerance and got weak over time. The "Play" function sends a fairly strong surge through there to get the thing moving, and I probably didn't help things running a lot of 90 min tapes thru it, which puts even more drag to get started.

Signs that it's getting weak? Takes a while longer to start, when "Play" is pushed. I figure it finally just took out the transistor.

Anyway, got all my old tapes transferred, and it now sits by the couch...ready to push the "On" button, and hit "Record".

Brad1

[Enzo]

I have a dead Porta 1 sitting here. I know it needs some work, but I also know I will never do it. No market for it. I think we removed one of the controls on the mixer and maybe a link in the transport to get another unit running. SO it is a parts unit now.

[Brad1]

Yeah, I just wanted to get all my old tapes transferred to the computer, and it died right in the middle of that, a while back. Otherwise, I wouldn't have bothered. Plus, I have a bunch of still-wrapped brand-new tapes that would go to waste if I didn't fix it.

Figured I'd just use them for quick recording of ideas when I'm sitting around noodling, and finding different chord progressions while going through "The Guitar Player's Songwriting Bible", which presents chords a different way. It's kind of basic, but interesting. Instead of just listing the chords according to their alphabetical name and maj, min, etc., they start with, say, A major, and then list a bunch of chords under that can work well with that one, including "common follow-up chords", "inversions", "non-diatonic", "no-thirds", "tonic pedal", "9ths", "7ths", etc. Kinda throws different ideas for what else to try, instead of just going for what you know. Find a related chord to the first one, turn to the second chord's page, and find a third (possibly unusual and not-thought-about) one. Been finding some nice, unusual sounds using that little book.

Anyway, that's why I fixed that old thing. Plus...just to see if I could. Possibly, other folks have/had the same dilemma. Since I now have all the tapes transferred, I wouldn't bother, again.

Brad1

[dai h.]

I have a dead Porta 1 sitting here. I know it needs some work, but I also know I will never do it. No market for it.

looking at the some of the recording oriented forums, I would say there is. Probably, someone will buy a working one if you put it on ebay.

[Enzo]

Possibly, there are people buying all manner of odd things. But at $60 an hour, how much time should I put into something I'd have to track down parts for in order to sell it for $20-50? A quick look on ebay and someone is ASKING a lot for one, don;t know if he'll gat it. I saw on the side someone selling the rubberized knobs for $10 each. At that rate I could part it out and sell the knobs, there's $250 if they sell.

I am not picking on the unit, it is a very flexible and useful machine, if dated, and the last thing I want to do is criticize someone's gear. I only meant that MY unit is WAY down my list of projects.

[dai h.]

sure, I suppose it might not be worth it. Might be able to get more if the unit is something that was refurbished by a professional.

I am not picking on the unit, it is a very flexible and useful machine, if dated, and the last thing I want to do is criticize someone's gear. I only meant that MY unit is WAY down my list of projects.

personally the notion that they are special seems a bit romantic and more and more on the impractical side as time goes on (tape does sound a bit different but I tend to think it's mainly about songs, performances, recording technique, arrangements, etc. more than the gear--not that gear doesn't matter at all). However, I guess it all depends on the person, maybe the style of music and so on.

[Bucko]

I know this thread is super dead, but...I have a Porta-One that's needs help. I fixed the loose spring issue with glue, thanks to all the advise I found online. Unfortunately, the Flywheel belt is so loose it falls off. Does anyone have extra belts I could buy?