Tascam 464 and 488 head base pressure spring / plate - how do you get this part out?

[cjacek]

Hi all,
Attached are a couple of photos. Do you by any chance know how to remove this long metal silver pressure spring (or pressure plate) in the middle of the photo? It needs to be removed in order for me to remove the head base assembly. I tried to slide it all the way down, hoping the larger hole above would let me pop it out but it won't go. Thanks in advance for your help.

 

[sweetbeats]

Hey, Daniel! IIRC…and I wish I had one here to verify…but you should be able to slide that spring plate *upward* away from the head base assembly so the forked end can clear the lower pin, and then you’ll be able to slide it back down toward the head base to clear the top pin through opening in the top of the plate. It’s one way or the other. I remember struggling a bit the last time I had to remove one of those. Regardless I recall it was close clearance, and I had to flex the spring plate to effectively reduce the length to get it to clear. Hope that helps!

 

[cjacek]

Hey Cory, now how did I *sense* that you were going to respond? Thanks my friend. Do you by any chance recall the tool you used, like whether it was needle nose pliers or screwdriver and how you tried to coax that plate out?

 

[cjacek]

Cory, no worries, I was able to get it out. After giving it another closer look and trying a few things, including using needle nose pliers to just pull it out from the top, I stopped and just put a small flat head screwdriver in that larger opening above (the above pin), through that hole, horizontally, from the top, where the flat head was sitting on top of that pin and I just pulled up and, wow, that spring plate flew up so unexpectedly, that it kind of gave me a little scare.

 

[cjacek]

...but, the way I did it, the spring plate needed to be pulled down (toward the heads) in order for the pin to almost clear the larger hole above. I then used the screwdriver method as per above. I then had to obsessively examine the play/rec head to make sure the spring plate didn't nick it while exploding upward, as I heard some metal to metal sound. I should have known and should have held it in place using my other finger. But I'll just leave that for the next person reading this, having the same issue.

 

[cjacek]

In process of disassembling of the cassette mechanism to clean it good, as the former owner (who gave me the 464 cheap) had used some kind of spray lubricant to generously and blindly spray the reel tables and area, with the hope it would fix it. Oil all over the place. All it needs is a good clean, removal of the plastic gears (which are gummed up - hopefully not cracked), cleaning those and re-lubricating and putting on a new capstan belt. Going slow, this will take a while. Then it's to the mixer section and casing, similar story, very dirty condition. This might be an "a la Cory" treatment or thereabout.

 

[sweetbeats]

I think I used hemostats, Daniel…and the key was sliding it in whatever direction got me closest to the plate clearing one of the pins, and then using the tool in the middle of the plate (maybe I used a spudger?) to bow it up and help provide the last little bit of clearance. I was thinking the action was to slide it up and away from the head base first, but you have it in front of you and would know better which direction gets you closest to having clearance…

Terrible idea blindly spraying line anywhere near any tape transport. Good luck. Yeah the reel tables have to come off, everything cleaned, and new lubricant conservatively applied to the spindles.

The head base motion assembly (the gears) are more prone to cracking I think in the later gen transports, like the 134, 238 and 122 mkIII. Typically what I’ve found with something like the 424/464 is the gears just need to be removed and, like the reel tables, everything cleaned…conservative application of new lubricant to the spindles, good to go.

Keep me/us here posted and definitely reach out! Hope you are well. The 464 is a cool model.

 

[cjacek]

Thanks again Cory, sure appreciated. I will update again, tho maybe not as frequently as I'd like to (but I will). The 464, from what I can see thus far, although simplified in design, is still a pretty impressive 4-track. The access to remove the cassette compartment, for example, is very simple compared to earlier models. That cassette mechanism is pretty hefty too, 3 motors, large heavy flywheel, just one capstan belt. I'm not sure if going to plastic gears was a good idea (for the head-block mechanism), making it more difficult if one cracks (vs belt driven) but it's still a nicely compact and sophisticated design. That they managed to cram every imaginable feature into it, is double impressive. Anyway, be well my friend.

 

[sweetbeats]

Yeah there’s nothing wrong with the 424/464 transport at all…similar to the 488, 644 and 688 too. That’s the thing…there are a LOT of them out there. So it’s not a challenge to find spares if absolutely necessary. And while the gears raise an eyebrow, I do like it better than a belt. And the only reason we question the gears IMO is because of the failures, and that’s only because of aged grease. That’s not a design flaw, that’s a preventative maintenance flaw on the end user if left unaddressed. Otherwise the gears even being plastic have the potential to last a long, long time.

I still think my favorite Tascam cassette transport is the original 122…this is more from an aesthetic standpoint, but it looks more like a miniature open reel transport…the capstan flywheel is truly huge…the biggest of all of them. And all of the mechanism actuation is by solenoids…like the same size you might find in use for the brakes on an open reel Tascam multitrack. As far as cassette transports go, it’s a beast.

My favorite cassette multitrack transport is the Audio Technica AT-RMX64, which was made by Sanyo. I like it because of the direct-drive capstan servo motor assembly, like the Tascam 122mkIII and 238, but minus the surface-mount electrolytic caps that cause the failures with those assemblies…everything is through-hole on the AT-RMX64 transport…and the head-base motion mechanism…the best I’ve handled because instead of a belt or toothed gears it uses a worm-gear drive and camshaft with followers that actuate switches for the feedback to the control system…less moving parts, more compact and reliable…but like I said the 424/464 transport is a good design and with proper maintenance can be in service for a long, long time. It’s an effective design.

 

[cjacek]

Fascinating, as Spock would say. Yeah, absolutely Cory, it's a preventative maintenance flaw rather than a design flaw. Same with some VCR's and even high end Sony Walkman's, which use small plastic gears, the grease ages, hardens, then people try to use the machines, the motor does its best to move the plastic gears hardened with grease and the teeth or the gear cracks.

 

[cjacek]

Hey Cory (and everyone who might be reading ). Just a small update and a quick question. So I almost totally disassembled the cassette mechanism, cleaning it thoroughly. The fine oil like substance that I mentioned earlier the previous owner sprayed in there, pretty much got into every crevice and I had to clean it all out. Still in the process. Will have to remove some of the back too (including the small PCB) to check for oil residue there. Anyway, my question pertains to the area pictured, the circular PCB. Is there supposed to be some grease there, on all of that brown and gold surface of that PCB? Please see photo.

 

[sweetbeats]

Hey, Daniel…IIRC I’ve always encountered some lubricant there…non-conductive I assume . I think in my experience it’s not been dry or hardened and I redistribute it to re-cover the contact tracks and call it good.

 

[cjacek]

Thanks Cory, I'll just probably leave it alone then. I'm glad I asked 'cause my first thought was to clean it. About the plastic gears, do you think it's necessary to clean the old grease off and re-grease even if these move freely and the grease has not hardened? I'll be checking each for this issue. Although that hair and pieces of debris do bother me a bit...

 

[sweetbeats]

I think I generally take the assembly apart and clean off the old grease regardless…not the teeth, but the spindles themselves and the gear bores and apply new grease…maybe add a little to the gear teeth, but if the grease seems to be in good shape and things are moving freely I think it can be left alone. It’s question of how long will it stay that way, and whether or not you’ll be back in there at some point in the future. And because I don’t know answers to that question I refresh things when I’m in there because I can’t get comfortable with the unknown. But think maybe there was one time I was working on a transport like that and was surprised the grease seemed “like new” and everything was working well, so I did leave it alone.

 

[cjacek]

Thanks Cory, much appreciated. Do you recommend (when needed) also cleaning the actual holes where the spindles go?

 

[cjacek]

Sorry, never mind, you said "gear bores" = the holes where the spindles go. Sorry.

 

[sweetbeats]

Yeah, yeah that’s what I mean there. Yeah I do and they can be a pain to clean because they are small diameter. If the grease is hardened often it can be knocked loose with a toothbrush and fully removed with compressed air. That’s been good enough. Sometimes I can twist a thin piece of rag cloth small enough to shove that in there to wipe as well. The latter would be the thing to do if the grease is not dried up.

 

[cjacek]

Thanks Cory, much appreciated . So a little update (with photos), going further with the disassembly: That plastic "C-Gear" (seems to be a very common issue on the 464 and 488) was totally seized up and basically crumbled upon removal (photo). That gear was prematurely aged and yellowed badly (I wonder what is so common about this particular gear - maybe TEAC subcontracted an outside company to make this part, which was made from substandard materials?). The other gears absolutely fine. Still I managed to clean these, along with the spindles. Funny thing, that spindle where the yellowed bad gear was, has gone tarnished or something, it's mostly black, the slippery chrome has mostly gone. I cleaned it well but it's still like that. I'm thinking it still should work fine once I grease it and put on a new replacement gear. It's not like it's a super critical element. Unless you'd recommend something? Another potentially awesome thing I found (rather surprising) but for some reason didn't register mentally before, when I was taking one of the photos, is the seeming option for the 464 to take Type 1 and Type 2 tapes, by way of the tape type auto selector (see photo) upper outer left and right, those things sticking out, typically only found on audio only decks. I also noted (when taking photos of the tarnished spindle) "Cr O2" labelled on the back of the PCB board (behind the auto tape selector), which I found odd, unless it also enabled Type 1 selection. I don't recall these being standard on the typical portastudio. So unless these are just "dummy" auto tape type selectors, which don't do anything, then this is awesome.

 

[sweetbeats]

I’d have to look at the whole gear assembly, but it’s possible the “gear C” experiences greater load, or lesser, so it was made out of different plastic, which unintentionally and unknowingly breaks down faster than the others…becomes brittle…something like that. It must just be a different plastic and likely by design. Or another possibility is, similar to what you are saying, if they didn’t make the gears in-house and outsourced them, which is not uncommon at all, the set of gears in your 464 may have come from different manufacturers OR different production runs and the formulation changed…this is highly possible because Teac may have ordered amounts for stock based on price-break quantities and then stock is depleted at different times for the different gears…so the gear set could be made up of gears manufactured at widely varying times and even from different manufacturers, and only time tells us of the ramifications. I think this is also why an old tape machine can have rubber components that are a mix of dried out, turned to goo, and still supple; different sources, different times for the parts all assembled on one machine.

I’ve encountered that tarnishing before on the gear spindle and IIRC I just made sure all the old grease and any other foreign material was cleaned off, polished it up as best I could with a piece of broken-in fine scotch-brite pad, and put it back together. I agree if it’s actually lost its plating, that is a really, really minor difference in the diameter of the spindle and I think that’s of no consequence here…clean it up, new grease, off we go.

Regarding tape type: I’m pretty certain, and my certainty is reinforced by the manual set, the 464, like other machines in the 400 series, is intended to use Cr02 tape only. Cassette machines that are designed for multiple tape types have manual or automatic switching that drives different bias levels and record EQ settings. The 464 doesn’t have any of that circuitry. According to the schematics the two switches are for 1. sensing a cassette is loaded and 2. record safety. That transport and/or the switch PCB may have been used in multiple different machines including Teac or Tascam consumer-format decks designed for multiple tape types. I could totally be wrong…I know there were a couple different versions of the 464 including one with an onboard BBE Sonic Maximizer circuit, and my manual set only covers what I think is the more common version.

 

[cjacek]

Thank you Cory, much appreciated, thanks for your time. I will update again with a longer post and maybe some photos too.