anyone familiar with Tascam 464?

[dai h.]

hi, bought a junker Tascam 464 4-track Portastudio--crappy, grungy, dusty and grimy condition (bit odd Japan-only model with an onboard BBE sonic maximizer instead of the XLR inputs on the export model AFAIK). It was really cheap (about the equiv. of 10 bucks) so I purchased it thinking the worst case scenario would be some backup knobs, pots, and opamps for my 488mkII.

I Tried plugging a gtr. into a mixer channel and it seems to work but, a motor (?--sounds like) is bad and making a lot of annoying noise. I've been trying to figure out how to disable it (I don't care if the tape deck section works) and as far as that I've been successful (unplugged one of the connectors going to what looks like a PCB to control the motors), but after a while I lost the LCD display. Variacing down the AC voltage (around 60VAC--line is 100VAC) brings it back and it seems to be stable and working (running it maybe 45min. or so). So it seems like I've lightened the load too much disconnecting the motor and whatever else on that line causing the voltage to rise too high to the LCD monitor.

Anyone know of a better way to disable without getting the LCD problem? Tried searching the forum and old archives but nada. Probably a longshot but I guess there's nothing to lose in asking. Thanks.

[HardRockHenry]

Maybe you should plug the wire back in ? As far as the Tascam's , I've heard mixed reviews.

[dai h.]

right but then that brings the noise from the tape deck section back. It seems a bit of a shame to just cannibalize it so I wonder how much it would take to fix it. Seems pretty solid, well made inside. Probably pretty nice when it was new.

[Enzo]

The display runs on +5vDC. No connection to the motor circuits. I'd bet either the display is bad, or the +5 supply is running unregulated. Unless you unplugged the entire motor control board, which is where the 5v regulator lives.

The motor has four wires, and should connect to the board by a 4 pin connector, just unplug that. We are talking the capstan motor, which runs all the time. Ther are two more motors on the transport. Reel motor and cam motor. They share another 4 pin connector, adn if they are noise, unplug them as well.

None of this should have ANY effect on the display. Unplug or dewire the motors themselves, not thier control board.

[Paleo Pete]

I don't know anything about the 464, but my 414 makes noise too if I run the tape. I don't normally use it except for the occasional practice track if I want to remember something long enough to work it into something better. Tape noise is not an issue, just getting it on tape so it's not totally lost.

To record with it I run the monitor signal straight into the computer running Audacity, no tape noise, it's never even turned on. That means multitracking is by software rather than on tape, and they have to be set in synch to be usable since the average sound card can't "multitask" - play and record simultaneously.

I'm curious though, your post sounds as if it makes tape motor noise whether actually taping or not...it seems if you have it wired right, it should still send a monitor signal to an external amp when the tape is not running at all. I don't even have to start mine and pause it, just turn the machine on and set the right buttons as if I were going to record on tape, then just not start the tape and send the monitor signal to the computer.

I downloaded the manual for the 414, it has the proper output noted to use as a monitor, routed to a separate amp, and it works when the tape is not running. I'm not familiar with the 464, but it seems it should have a similar capability.

EDIT:

I think Enzo might have just explained it while I was typing, the motor runs all the time. Mine doesn't, or if it does it's real quiet...

[dai h.]

thanks Enzo and Pete.

(Not sure really but) could you damage something by letting it run with the noise affecting connector unplugged? For now, I decided just to put it back the way it was and in that state the display comes back (as well as the noise).

The motor has four wires, and should connect to the board by a 4 pin connector, just unplug that. We are talking the capstan motor, which runs all the time. Ther are two more motors on the transport. Reel motor and cam motor. They share another 4 pin connector, adn if they are noise, unplug them as well.

I tried unplugging and plugging back some of the connectors in the vicinity and narrowed it down to one (something in the middle IIRC; rightmost or on the PCB one over to the left) and that directly affected the noisy motor, but the display wouldn't stay on.

Pete, I bought this as basically "junk" (broken) so it isn't a healthy unit. The tape deck section didn't(and doesn't) work. The noise is hard to describe exactly but maybe it's a gear("Rrrrrr" with a bit of intermittency)? The speed knob affects it as well as the HIGH/LOW (normal/x2) tape speed switch (the noise rises in pitch at normal speed--which is a bit counterintuitive but that's what happens). I also do know that at least with my (working) 488mkII, I get a bit of motor noise if a cassette is present inside the unit but stops when you take it out.

edit: oops sry got the TAPE SPEED switch description backwards (goes faster on "HIGH" rather than "NORM").

tried turning it on again, and (so far as the ones I could confirm) the function buttons connected to the switch seem to work ("RECORD FUNCTION" buttons and BBE on/off indicator).

hmm... well just now the noise went dead then the display. Then tried turning the AC voltage down, which brought the display and noise back but if I raise the AC towards line level (from about 80VAC) they both go dead.

[Enzo]

ANything you unplug will not harm anything else. There is no equivalent to operating a tube amp without a speaker.

Dai, lift the transport out. Look at the capstan motor. Follow the wires from it to the circuitboard right there. Pull THAT connector. SHould be a white connector, four pin, P2. In fact, the transport has three four-pin plugs. That one, then the other two motors are on P4, which is red. And also the black one, P3 which carries the position sensors. You can unplug them all. They are along one end of the small board.

On the mechanicsm control board, the three pin black P5 is raw power TO the board, and the 11 pin ribbon sends +5 to the circuits, including the display. Do NOT unplug those.

If you lift the transport out, you should be able to just disconnect any cable trailing from it. Even the head cables. They might add some hum, but only if you select TAPE on a channel, andf I don't see why you'd do that using it as a mixer. ir just unplug the transport cables and leave the heads connected.

[dai h.]

hey Enzo, sorry for the slow reponse

tried firing it up again and unplugged the white P2 connector and I get nothing from the motor, but the display keeps going dead. It stayed on for a while powering gradually up to line voltage (100VAC) but after a while went dead. Then, lowered it to somewhere around 60VAC then came back on. Tried working up slowly and it goes dead around past 75VAC. I think I'm just going to put the screws back on and put it away/move it out of the way for a rainy day just in case I need an opamp or fader or something to cannibalize. Thanks for the help!

edit: just to add, I've kept it on for a while at around 65VAC and the display stays on but increasing AC to around 77VAC makes it disappear

[Enzo]

Then you have more issues than just the motor.

[dai h.]

yes, maybe I damaged something during the initial plugging/un-plugging of connectors

[jrfrond]

Please allow me to post a page from our website:

http://www.dbmproaudio.com/ps.html

[dai h.]

yes, you are totally correct but I didn't really care too much about trying to repair it. It's like I mentioned above, some of the parts are common among the series (out of which I own a 488mkII) so for example the NJM4565SD opamp (S suffix =single in-line package, extra D suffix = low noise version) you can't just buy off the shelf(I'm guessing Tascam ordered a bunch in mass quantity from New Japan Radio corp. for their product), so it can make more sense to cannibalize a broken unit. (It was sold cheap as a defective unit.) It might make sense if I knew how to repair cassette decks and had the necessary equipment, but I don't so I think it's just best to use it for spare parts.

[Enzo]

The power supply should be easy enough to fix. I don't think you hurt anything by disconnecting anything. it just failed, that's all. These circuits are not handling any power, being unterminated will be no more stressful than leaving the battery out of your walkman will stress it.

dai, there are other low noise op amps that would also work. You are not limited to that one. 4565 is older these days anyway, look for maybe a 4580. Or leave the 45xx family and try a 2068 or something.

John, I think it depend upon your market. I can say that here in my market, the average repair for an old Tascam casette multitracker is not nearly that high. I don't doubt that in NYNY it costs a lot more. I am always leery of "average repair cost" being applied to individual repairs. A couple of head replacement, realign, and calibrate jobs will seriously skew the average in any shop. CERtainly a new power jack, or the common failed pass transistor in the power supply won't cost that much. Not here anyway. I had a regular customer bringing his big Fostex 16 track for service. Had to replace the head on it once. That was 15-20 years ago, but it still cost him over $1000 back then. Another time he had a bad input jack, and another re[pair was something dumb like a noisy control or something basic. Average repair cost for the three would then be maybe $350-375. But that amount doesn't remotely resemble any of those repair invoices. SO I avoid "averages" when discussing repairs. I will estimate specific repairs, but that is different.

That said, I don't disagree with the message. With the performance of even the cheapest hard disc recorders these days, I am surprised people still use the cassette things. WHy throw money after it. Which I realize dai is not doing.

The only connection I would make between the motor thing and the displaty problem is that in trying to track down the motor solution, you likely compromised a connection elsewhere in the circuit.

[dai h.]

thanks enzo. I thought I could pull it off since I've disconnected the tape deck portion successfully on an old Porta 2 but I guess not.

As far as the opamps, the old Porta 2 used NJM2068SD if memory serves while the 488mkII has the 4565. I know from trying to plug opamps in and out that many times other ones can be subbed but with the 488mkII (which had about 2 bad when I got it used) I got apparent oscillation when I subbed NJM5532S'(lost signal), however I figured out how to deal with that (attaching 100 ohm Rs directly in series with the outputs--seems like a useful "trick" to help stabilize opamps in parametric EQs). A couple were bad (so they *needed* to be replaced) but I didn't really notice any difference (improvement) in sound so IMO not really worth doing, esp. since 5532s tax the power supply more. Also some other goofy tweaking cap/resistor subs with parts I had like Black gates, tantalum, metal film Rs but again nothing really noticeable in the result.

[drewl]

Just got one of these in for repair.

It's running really fast and has no speed control, either high or low speed or the pitch wheel.
it just keeps screaming along.
Even stuff I recorded on a 4 track at high speed is fast.

Anyone have a schem or link to the motor control circuit?