Tascam Portastudio 464

[Monkey Allen]

I bought this a month and a half ago or so and have only just had time to give it a thorough workout. Everything works, all metering seems accurate, the transport runs well...except these things:

a) Track 1 records but playback volume oscillates between normal volume and lower volume. It kind of pumps, well not really pumps...more like the volume wavers between normal volume then it will go down for a while then back up then back down then up. That kind of thing.

b) Track 4 won't record. Not sure about this. I did get a tiny little weak signal. But you have to crank everything on track four including all eq just to hear the faintest trace of what was recorded. I'm pretty sure I'm arming it properly.

c) The headphone jack slot is very temperamental. The headphone jack has to be plugged in just so or one side (the right side maybe, can't recall exactly) will cut out.

Tracks 2 and 3 seem perfect. They record perfectly and playback perfectly.

If you know anything or have any tips, let me know. I guess it is getting harder and harder to find discussions online these days that pertain to the specific issues with your machine.

Thanks a lot

 

[Slouching Raymond]

The pumping sounds like a power supply problem. Not enough power to go around.

 

[sweetbeats]

The pumping sounds like a power supply problem. Not enough power to go around.

Could be, but in my experience edge track issue like that on a 4 to 8 track cassette multitrack machine usually tie back to a bad pinch roller. For whatever reason I’m finding consistency across multiple makes of cassette machines where the pinch roller still seems serviceable to the naked eye and to the touch (not tacky or gooey, not hardened or slick), but if you actually remove the roller and measure as best you can with a dial caliper the diameter of the roller from one side to the next it is slightly smaller at one side, and you can even see this if you look at it under the right conditions (good light, white background…) The slightly smaller diameter end will cause the tape to wrap slightly less on the capstan which will draw the tape to one side of the tape path…now, it’s a cassette, and there are guides, so the tape can only go so far and then it wants to walk back…then draw to the side again…it’s all very slight but it’s enough to cause tape-to-head contact issues for at least one edge track. Is the pinch roller new on your 464? If not I highly recommend you get a quality replacement. I’m not incentivized to say this in any way…just a super happy customer…but I highly recommend getting a new roller from Athan Corp. I’ve used their rollers on three cassette machines…Tascam 238 and 122-B, and on an Audio Technica AT-RMX64. I also have one ready to put on a 244 at some point. The 238 had typical edge track issues I just thought were part and parcel to the format…Athan roller went in…edge track issues gone…first time I’ve had that success on any of the half a dozen or so 8-track cassette machines I’ve owned and worked on. Anyway, consider that for your track 1 issue.

For track 4 I suspect a bad relay, but you’d really have to suss that out…verify the record amp is working…verify it’s not a problem with the head…does it play back on track 4? Record on track one and flip the tape and play back. If it’s fine on track 4 with the tape flipped it’s not the head or head wiring or playback amp. You’ve thoroughly and properly cleaned the head right? The tiniest particle of debris or buildup can vastly diminish or outright prevent signal. So there are some ideas.

Your headphone jack issue…start by reflowing the solder joints for the jack if it’s board mounted. I think it is in that machine and the PCBs are all phenolic type (lower quality and more easily damaged), so decades of plugging and unplugging may have compromised the solder joints but you can reflow and refresh usually. If the damage is greater than that and traces are damaged you can bridge those and solder the bridge in. Sometimes though it’s the jack itself and in that case you just need to get a new jack.

 

[Monkey Allen]

Could be, but in my experience edge track issue like that on a 4 to 8 track cassette multitrack machine usually tie back to a bad pinch roller. For whatever reason I’m finding consistency across multiple makes of cassette machines where the pinch roller still seems serviceable to the naked eye and to the touch (not tacky or gooey, not hardened or slick), but if you actually remove the roller and measure as best you can with a dial caliper the diameter of the roller from one side to the next it is slightly smaller at one side, and you can even see this if you look at it under the right conditions (good light, white background…) The slightly smaller diameter end will cause the tape to wrap slightly less on the capstan which will draw the tape to one side of the tape path…now, it’s a cassette, and there are guides, so the tape can only go so far and then it wants to walk back…then draw to the side again…it’s all very slight but it’s enough to cause tape-to-head contact issues for at least one edge track. Is the pinch roller new on your 464? If not I highly recommend you get a quality replacement. I’m not incentivized to say this in any way…just a super happy customer…but I highly recommend getting a new roller from Athan Corp. I’ve used their rollers on three cassette machines…Tascam 238 and 122-B, and on an Audio Technica AT-RMX64. I also have one ready to put on a 244 at some point. The 238 had typical edge track issues I just thought were part and parcel to the format…Athan roller went in…edge track issues gone…first time I’ve had that success on any of the half a dozen or so 8-track cassette machines I’ve owned and worked on. Anyway, consider that for your track 1 issue.

For track 4 I suspect a bad relay, but you’d really have to suss that out…verify the record amp is working…verify it’s not a problem with the head…does it play back on track 4? Record on track one and flip the tape and play back. If it’s fine on track 4 with the tape flipped it’s not the head or head wiring or playback amp. You’ve thoroughly and properly cleaned the head right? The tiniest particle of debris or buildup can vastly diminish or outright prevent signal. So there are some ideas.

Your headphone jack issue…start by reflowing the solder joints for the jack if it’s board mounted. I think it is in that machine and the PCBs are all phenolic type (lower quality and more easily damaged), so decades of plugging and unplugging may have compromised the solder joints but you can reflow and refresh usually. If the damage is greater than that and traces are damaged you can bridge those and solder the bridge in. Sometimes though it’s the jack itself and in that case you just need to get a new jack.

Ok, very helpful, thanks lot for all those details. I should give a little more info...

The unit was described as fully serviced and fully functioning. When I asked the seller for more info, he said that it had been serviced 2 years ago and that it had sat completely unused since then. So that would be 2022 roughly. He also said he checked out all the functions before shipping to me and all was good. I take that with a grain of salt though really. Testing all the functions requires a bit of leg work. If anything, he might have just tested some playback and maybe a track 1 record. If that.

Underneath the unit there's a sticker for an audio repair/ service company specializing in vintage/ old gear which indicates it had been looked at to some extent. It's impossible to know what was or was not done. Anyway...I searched the repair company and they look like they haven't been active since about 2020. So that probably means the unit was serviced not 2 years ago...but probably 4 years ago. What happened to it since then is anyone's guess. Of course there's always the chance that it was serviced by the repair company on the sticker 4 years ago...AND by someone else 2 years ago. You just don't know.

None of this surprises me about such a unit. They are so old and so many of them get sold as "fully serviced" when in fact they have issues. I still kick myself for selling my mint condition and 1 owner (me) 414 mkii 2 years ago. But that's another story.

Anyway, back to the 464. So what I mentioned above fleshes out some hazy details...but here's some other stuff:

I'm almost certain that when I first did some tests (6 weeks ago) , track 1 and 2 were ok. I fed source from my DAW into those 2 tracks and they both recorded and played back fine. As for track 4...I am pretty sure it plays stuff back. It just does not seem to record. But going back to track 1...6 weeks ago I'm sure it was fine. And even in the last couple of weeks I'm sure I've been doing tests and recording onto that track no probs. Today though, I wanted to actually start a song for real so I used one of those all in one cassette headcleaner/ demagnetizing tapes that you need to drop some of the cleaning solution in. Right...so before starting the session this morning I used the headcleaner/ demag cassette...only it's a real mess trying to drop the cleaning solution through the slot in the cassette housing...so I got probably too much solution in there. Then I tried to shake the solution out and wipe it off etc. I also ran the cleaning cassette 3 times. The instructions say 1 time is all you need. So, not sure if my 3 times did more harm in some way than good.

So I go to feed signal in from my DAW...a mono drum track to track 1 in the 464 and bass guitar to track 2. The track 2 bass is good but track 1 drums is like I describe...waving, oscillating volume. I figure maybe I got too much cleaning solution on the heads or something. I clean them with a Q tip thing gently. I rewind and record again. This time the track 1 problem is still there but maybe not as bad. I repeat the process and record again..,again there is some small improvement it seems...but the problem is still there. I try it one more time, cleaning the heads, rewinding and recording again. It's not as bad as the first time but the issue is still there.

So I pack up and come here. So that's where I'm at. That's as detailed and accurate as I can describe I guess. I'm sure track 1 was performing fine before. Not sure if the cleaning cassette played a roll. Not sure if the actual tape I'm using is bad (although I doubt it). Track 4 remains bad. I have a feeling when I first got the 464 I tried to test track 4 recording and it didn't work. At that time I just put it down to rushing and not having everything set right and that I'd look into it later when I had more time.

So track 4...no record.
Track 1...pretty sure it was good...right up until I used the cassette cleaner/ demag thing today.
Headphone jack...problematic.

Unfortunately I have no skills inside these things.

Anyway, if anything I said jogs some ideas or whatever, let me know. I appreciate it. If I take it (which I probably will) to someone to repair, it'd be good to have a detailed analysis and list of possible causes to give to the repair dudes.

Thanks

 

[sweetbeats]

I really appreciate your transparency. Sometimes, when I’ve done something I wonder in my gut if it caused my problem, it’s hard to publicly say “I did that”. But it is ultimately helpful and there’s certainly no judgment here.

Step 1: place that cassette cleaning/demagnetizing cartridge in the nearest waste bin. I’m serious. Get rid of it. Yes the tape path should be cleaned with cleaning swaps and proper cleaning solution, and demagnetized using a proper wand-type degaussing tool. The cartridge cleaner/demag devices do a poor job cleaning, and may actually create more issues…and they don’t degauss well at all. If the pinch roller is suspect, that issue could be exacerbated by the cleaning tape because cleaning solution can go where it shouldn’t go, including on the pinch roller. Get a really good light and a magnifying glass or jeweler’s loupe and look at the rec/play head closely. Use some good cleaning swabs and 91% or better isopropyl alcohol or pure denatured alcohol…or a quality dedicated product…make sure the head is spotless. Try the flip-the-tape test and report back. Inspect the pinch roller…any visible deformities? Clean the pinch roller with water or if it seems soiled you can use glass cleaner. Whether the unit was “serviced” 4 years or 2 years ago is really irrelevant. I rarely see serviced units where the seller has actually gone to the trouble of replacing the pinch roller and reel table drive rubber, because you typically have to completely remove and partially disassemble the transport to do it, and many are not comfortable with that. And there is not one cassette machine from the 80s or 90s at this point that doesn’t need that done. Period. I always replace ALL the rubber on any machine I service and flip. So look in there and do what you can, but don’t use that cleaning tape anymore. Again, no judgment. If using it exacerbated the problem, it’s not that you killed it…just maybe brought something underlying to the surface you would encounter eventually anyway. At least that’s my opinion.

In what part of the world are you located?

What kind of tape are you using?

The 464 is a cool machine…a prequel to the 424mkII. Is yours the one with the onboard BBE Sonic Maximizer circuit or the XLR mic input jacks? There are a couple versions of the 464.

 

[Monkey Allen]

I really appreciate your transparency. Sometimes, when I’ve done something I wonder in my gut if it caused my problem, it’s hard to publicly say “I did that”. But it is ultimately helpful and there’s certainly no judgment here.

Step 1: place that cassette cleaning/demagnetizing cartridge in the nearest waste bin. I’m serious. Get rid of it. Yes the tape path should be cleaned with cleaning swaps and proper cleaning solution, and demagnetized using a proper wand-type degaussing tool. The cartridge cleaner/demag devices do a poor job cleaning, and may actually create more issues…and they don’t degauss well at all. If the pinch roller is suspect, that issue could be exacerbated by the cleaning tape because cleaning solution can go where it shouldn’t go, including on the pinch roller. Get a really good light and a magnifying glass or jeweler’s loupe and look at the rec/play head closely. Use some good cleaning swabs and 91% or better isopropyl alcohol or pure denatured alcohol…or a quality dedicated product…make sure the head is spotless. Try the flip-the-tape test and report back. Inspect the pinch roller…any visible deformities? Clean the pinch roller with water or if it seems soiled you can use glass cleaner. Whether the unit was “serviced” 4 years or 2 years ago is really irrelevant. I rarely see serviced units where the seller has actually gone to the trouble of replacing the pinch roller and reel table drive rubber, because you typically have to completely remove and partially disassemble the transport to do it, and many are not comfortable with that. And there is not one cassette machine from the 80s or 90s at this point that doesn’t need that done. Period. I always replace ALL the rubber on any machine I service and flip. So look in there and do what you can, but don’t use that cleaning tape anymore. Again, no judgment. If using it exacerbated the problem, it’s not that you killed it…just maybe brought something underlying to the surface you would encounter eventually anyway. At least that’s my opinion.

In what part of the world are you located?

What kind of tape are you using?

The 464 is a cool machine…a prequel to the 424mkII. Is yours the one with the onboard BBE Sonic Maximizer circuit or the XLR mic input jacks? There are a couple versions of the 464.

Hey thanks. No worries at all with me being transparent. No probs at all to tell it all like it is. And I don't mind being told I did the wrong thing. All good. I'll have to get the right cleaning solution and all that and get in there and have a closer look. I did get a good light on the situation and magnifying glass and the heads looked decent to my inexperienced eyes. But yes, will have to get in closer. Not sure if I eye-balled the pinch roller as such. Yes it looks to be a very involved job to take these apart and do the necessary work. I can take lawnmowers apart and all that, work on carburettors but electronic/ tape devices like these...I'm very, very limited.

I'm in Australia. I'm using a new Studio Master 799 C60 High Bias Type 2 cassette and my 464 is the Japanese version with the BBE Sonic Maximiser. Sure is a good machine...when in full working order. I'll run more tests once I have the right cleaning stuff and will look into a demag thing. Thanks again for your advice. I see a trip to the repair shop in my future and the parting of large sums. Finding repair guys is one thing...finding repair guys who know what they are doing is another.

 

[Monkey Allen]

Ok some good news, some old news and some different news. Here's what's what right now.

This part is crazy...previously track 4 wasn't recording (seemingly) or playing back for me. This is 6 weeks, 4 weeks ago. Bare in mind that I've only had the time to test this 464 out here and there, when I can. So back then with track 4 I researched and came to find out that if you had the rear "Sync" button engaged/ on, you'd not get playback from track 4. So I switched the Synch button to off and all good, track 4 working. Yesterday when I was doing tests and getting nothing from track 4 I did not realize that at some point I must have accidentally engaged Sync again. I turned it off just now and the track 4 stuff I recorded yesterday was there playing back. So, my bad, as the kids say. Track 4 is ok.

But...here's the deal now...Track 1 & Track 4 exhibit this fluttery, wavy, warbly, oscillating volume issue like I described before. I notice now that track 4 has it as well as track 1. These are the outside tracks I assume. When I say volume issue...as far as I know it could be some kind of frequency warble where a certain frequency range comes and goes. This could be perceived I guess as volume oscillation. I find it interesting that the outside tracks 1 & 4 have this behaviour.

I really want to say that this warbly, oscillating issue was not evident before I used all this solution in the cassette cleaning tape...which I ran 3 times in a row. It could be that the solution and the cassette cleaning tape exacerbated some kind of issue like Sweetbeats said. I am not sure. I am very sure the issue wasn't present before I used the cassette cleaner and solution.

I guess I should add that Track 2 & 3 playback solid, no issues. Nice clean playback.

I'm attaching some images. Very hard to get a camera in there as the cassette door blocks a lot of access to getting in there and eyeballing the heads, pinchwheel etc.

EDIT (4 or 5 days since original post right above): Just listening to some old tapes I did ages ago on my 414 and the playback on the 464 is solid on all tracks. There's no weird track 1 & 4 sound issue at all. So this makes me think that the issues I heard on track 1 and 4 came about because they were baked into the recording I did immediately after running the all-in-one cassette cleaner with liquid solution and demagnetize combo thing. My theory is that I squirted too much liquid cleaner into the slot on the cleaning cassette. I then ran the cleaning cassette not once, the advised amount of times, but 3 times in a row (you know...to make it more clean!). Immediately after that I started doing my recording to tracks 1 and 2. Right after the recording I noticed that track 1 had that weird coming and going volume thing as described. I'm thinking that maybe there was excess liquid solution and as the tape ran through the pinch roller and all that the excess liquid was forced to the edges of the tape and interfered with the recording quality of the side tracks...while the middle 2 tracks stayed good. Just a theory. The natural next step in troubleshooting would be to record some stuff again. I can send tones or whatever out of my DAW to all 4 tracks and see how the recording goes. I'm hoping everything will be ok now that some time has passed and whatever excess solution has dispersed. I'll do that when I get the next bit of free time. I've got some proper cleaning stuff now and have one of those demag wands inbound. For now though, it's good that with playback all tracks are solid and playing back no worries. I think that's a good sign. I will continue the research.