Tascam 246 melted rubber help

J

Jimmy Sandals

New member
First, I'd like to thank Dr. ZEE and everyone else who has posted/provide information on 244/246 repair, it has all been a huge help in this!

I purchased a 246 recently that needed belts, tires and a pinch roller. I'm not particularly adept at this stuff, but with the materials online I figured I could give it a go. The belts and tires had turned into the dreaded melted goop, I got the belt bits out and am currently cleaning the idler wheels (that stuff is so hard to get off!) to get them ready for the replacement "tires" (washers).

The problem I am having with the melted rubber is on the motor pulley, it is covered all the way around with goopy melted rubber! It is also on contact points behind and in front of the pulley, and I am getting concerned about smearing it in even more places. Besides sticking with it and being careful, does anyone have a good way to get this stuff off besides qtips and alcohol? Any help would be great. Thanks!
 
Well, went ahead and pushed on through with alcohol, bits of paper towel, wipes, and qtips... for the most part, I think I was successful, minus a tiny smudge of goop I can see on the plastic behind the motor (part of the whole idler tire assembly). One more try tomorrow and I think I will be good. Also, the goop stained the tan "guide" wheel below where the tire assembly goes, as well as the plastic idler rims themselves... that stuff is awful! I'm still trying to clean everything but MAN -- what a mess!

Again, really want to thank the forum for guidance on all of this, I NEVER would have tried to do this on my own if that information wasn't available... As a furloughed government worker in this shutdown, at least I have some time on my hands to get this done!
Also, huge shout out to Tascam. They currently have everything on hand except for the tires, love how they continue to support their products without a blink -- oh by the way, I live in Hawaii and had my belts and pinch roller here within a few days of ordering. Awesome!
 
Also, question -- this metal sheet was screwed in over the mixer boards, does anyone know what the white/rust-colored (on edges) deposits are... is that just aluminum corrosion, or should I be more concerned? Also, are these sheets typical? I haven't seen any examples with these screwed in over the boards...
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Thanks!
 
Dude the pinch roller on my 244 turned to goo also (my fault, I must have accidentally got some alcohol on it) and I can't for the life of me seem to figure out how to get to it! Now it's just a glorified mixer...

Wish I could help, but keep on trucking, you'll make it!
 
Greetings!

Congrats on working through the goo.

For tough and/or messy jobs I'll use t-shirt scraps and iso alcohol to remove disintegrated rubber, and I also use 100% cotton makeup remover pads in lieu of or in addition to cotton swabs.

Those metal sheets don't look factory. I'll have to look in my 246 service manual to see. They are there for shielding and as long as they are properly grounded to the chassis ground, they are not likely hurting anything. As for the corrosion I can't tell for sure but unless there are other components corroding or possibly leaking onto and creating those spots, I suspect it is just surface oxidation from exposure to the environment. You know anything about the historical use and/or storage environment for this unit? I've seen that kind of corrosion on other vintage equipment just from the long-term exposure to normal environments an I don't think it is anything about which to be concerned.
 
Hey Hammerstone, look up some of the threads that Dr. ZEE has posted, it is a wealth of info for the 244 and will definitely help you out, there is a link in the threads to his website as well. I have been using it extensively on this project! Tascam had pinch rollers in stock, received one the week before last for this project and will be replacing it after I get the tires replaced (more on that below).

Sweetbeats -- found some makeup swabs, they work great and will be putting my old tshirts to use now too. I don't know much about the unit, the seller was doing so for a friend who had already left the island; got the impression it stayed in a (likely nonairconditioned) basement. Pics on Craigslist show it being used with a Firepod and a Duet, so hopefully the previous owner did right by it. Still, I too haven't seen anything with the metal sheet (2 screws into the chassis) and probably won't put it back on when (if?) I he everything replaced...

On that note, been having a bit of difficulty with the rubber washer tire replacements... I found some locally with what I thought were the same specs as suggested but GEEZ -- got blistered thumbs trying to "delicately" work the rubber into those tire rims with tweezers and small screwdriver! Any suggestions on a better way? Almost seems like the washers are too tall, too much rubber to actually fit inside. I dunno, if the idler tire assembly wasn't on backorder with Tascam i'd probably opt for the complete replacement route at this point (and if I don't, should get another washer as I think I may have slightly nicked an edge trying to wedge it into the rim).

Super frustrating, but definitely a great learning experience! Thanks again to all for the wealth of info on this forum.
 
sweetbeats said:
Greetings!

Congrats on working through the goo.

For tough and/or messy jobs I'll use t-shirt scraps and iso alcohol to remove disintegrated rubber, and I also use 100% cotton makeup remover pads in lieu of or in addition to cotton swabs.

Those metal sheets don't look factory. I'll have to look in my 246 service manual to see. They are there for shielding and as long as they are properly grounded to the chassis ground, they are not likely hurting anything. As for the corrosion I can't tell for sure but unless there are other components corroding or possibly leaking onto and creating those spots, I suspect it is just surface oxidation from exposure to the environment. You know anything about the historical use and/or storage environment for this unit? I've seen that kind of corrosion on other vintage equipment just from the long-term exposure to normal environments an I don't think it is anything about which to be concerned.
Click to expand...

Just FYI, my 246 has the same metal sheet, so I'm guessing they are factory?
 
Abcd

A) the RFI shield over the audio section is factory stock. It looks to be mylar sheets with a metallic foil implanted.

B) the marks on the RFI shield look like minor spill damage.

C) the way to get to the pinch roller on the 244 is to open up the bottom and completely remove the mechanism from the chassis & flip it over. Sorry, I don't know any shortcuts. I have one used 244 where someone just chipped the plastic cover in that certain place, under the cover plate, for easy front access.

D) I've had trouble finding the exact sized tires. I've been going with something a bit smaller that will stretch (that's PRBline tires). It's a tough and imperfect fit. The tire sits like a diamond cut belt when it's done, but it works! I couldn't get it in any further without risking damaging the wheels. I've found it easiest to completely remove the original clutch assembly from the chassis & motor to manipulate the tires onto the idler wheels. Definitely don't lose the microscopic sized C-clip that holds the clutch to the motor! (Unfortunately, that requires a pretty full teardown!) I've also been scanning the web for a better equivalent tire than the ones I've been using for a while. I've not gone plumbing o-ring shopping yet. There may be something in a round o-ring style that works, vs. the original square cut "tire". I've read the Dr Zee 244 pictorial, and it's a good reference, but I'd had to go in deep into a 244 long before this turorial went up.

PS: Tires and belts have become old school tech & therefore are harder to find. I believe Tascam had a custom sized idler tire for some of their products, back in the day. I've carefully measured the original Tascam 246 idler tire and haven't found anything equivalent in PRBline's documentation. However, the capstan and control belts are a much easier fit with PRBline belts, with PRB being the company that apparently owned the belt market back then. (PM me for the sizes).

:spank::eek:;)
 

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I've done this fix twice on the 246 over the years. Once with new idler tires from Tascam and once with faucet washers. Both ways worked well, but yes it can be a stretch getting the washers on. Careful not to mar or break the plastic with the screwdriver.
 
Thanks for the info on the RFI shield! I'll attempt to clean/restore it before putting it back on once I get the tires and pinch roller replaced.

I just called Tascam parts dept. again, new tires are still on back order so I may as well push ahead with the washers again. Took as best care not to chip or bend the rims, visually they still look ok (aside from the smeared in discoloration from the old black goo I couldn't get off) but the washer took a bit of a beating trying to massage it in.

A Reel Person -- when you say it sits like a diamond cut belt, do you mean at an angle all the way around evenly? I was curious about the possibility of leaving the tire on securely but sloped to one side (how it naturally wanted to sit when I first started fitting the washers). I just could not get it to sit evenly on/in the hub!
 
...

For the undersized tires I was using I wasn't able to fit it entirely back into the channel on the idler. I settled for leaving the tire rotated with one corner down, so it sits on the idler like a square belt. I made sure it was absolutely even all around and on both tires. I was wary of breaking the idler, so I didn't mess with it further or try to force it. If you break the idler clutch assy itself you'd be pretty much out of luck to repair it.

I had thought from some years previously that I could fit this tire entirely on both sides of the idler. It could be that I could make it fit properly if I took another stab at it, but I just wanted to get it replaced and move on.

It would be best overall to get a properly sized tire so that it would aid ease of installation and fit better, but you use what's available in a pinch. An O-ring would probably be as good a solution as sweating the tire size or going with flat rubber washers.
 
Haha... well I just double checked the dimensions on the washer, and the walls on these washers are 5/32in "tall" and 1/8in "wide", definitely not square at all and not the dimensions compared to those from Dr ZEE's tutorial. Oops. :) think I will go to the local hardware store tomorrow and look for some suitable o-rings.
 
Back up and running

A Reel Person -- I got a box of various O-rings and found some that worked out... kind of a this one's too big, this one's too small, etc... trial and error until I found one that worked. Not quite as much rubber sticking out as I'd hoped, but the thicker O-rings prevented the bottom wheel from fitting in to place. Tested the contact before putting the whole assy back together and it appeared to be suitable.

The pinch roller was much easier to replace than I had envisioned, thanks to the many warnings in different threads to make sure you know the position of the spring before you disassemble. I had a full replacement part from Tascam and after a few fumbles was able to get the spring where I wanted it and slid it on the shaft -- piece of cake! Even the C-clamp was less frustrating than I thought it would be, probably because the idler washer stressed me out plenty earlier... :)

Had a spare tape lying around and tested the transport functions, all seemed to go well save for a minor "swing" to the counter which I can live with. Cleaned up the shielding as best I could and buttoned her back up and now she is running great. Thanks again to everyone, hopefully all the electronics are working correctly -- haven't had a chance to fully op-test all the circuits, but did pop a tape from my 424MkIII in there just to test the VUs and at least channels 1-4 meters were functional, will crack the manual to learn the routing for the 246 to check the pgm VUs and start recording. Mahalo! :thumbs up:
 
That's awesome!

246 Tape Counter: is a wheel type magnet rotating on the top side of the tape mechanism with a hall effect transistor riding as close to the rotating magnet as possible without touching. Check this area that the transistor is properly placed & not touching or binding.

:spank::eek:;)
 

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Thanks Dave for the insight! The "swing" time in the counter isn't too bad and can work around it... Next time I have her opened up for whatever reason I will add that to the list to check out (although hopefully not any time in the near future! :) ).

She's all back together and aside from a few scratchy connections on the phones selector switches that I will attend to later, all of the innards seem to function properly and the 246 sounds great! Thanks again for all the help in this thread as well as the multiple other ones on here, great wealth of information.
 
I want to do this rebuild too. I'm glad to see this post because it's current and not 6 years old like a lot of them. One thing I've also considered is just buying a used but newer 4 track machine that is functional so I can finish transferring my old tapes to my computer. You mentioned that you popped in a tape recorded with the 424 MkIII and the VU's were all working fine. I was hoping you would respond as to whether the tapes actually playback fine on the 2 machines, that they are compatible for playback on all tracks. It's hard to find out if tapes recorded on one machine will line up (be compatible) with a different model 4 track recorder.
By the way check out Dynamic Technology Group for parts for these recorders by Tascam. I have one more Q. The C clamp size, do you know it or how to measure it? Just in case I lose it or it's damaged Dynamic sells them cheap but in various sizes. Thanks
 
C. Anthony said:
It's hard to find out if tapes recorded on one machine will line up (be compatible) with a different model 4 track recorder.
Click to expand...

All Tascam 4-track on cassette with dbx are compatible with each other. So are all the 8-track on cassette models. So for example, a 488 will playback a tape from a 238, just as a 424 will playback a tape from a 244 or 246. The only ones that are a bit problematic are tapes made on the original 144, which used Dolby B. In that case you can switch dbx off and get a decent transfer with no NR at all, albeit a bit noisier than desired.
 
C-ring

I had a point where either I "lost" the C-ring from the idler assembly, or it wasn't there to begin with, when I disassembled the previous 244. I looked for hours for it, shook the open unit upside down, etc. Nada. The worst case scenario would be to lodge it somewhere into the circuit assemblies, but I looked at some photos I'd made previously and I didn't see any distinct evidence that it was there to begin with, at all. Strange, but I wasted several hours looking for it.

I called Tascam Parts, and as luck would have it, they have the C-ring (E-ring) available! It's the same size on the idler as on the pinch roller assembly, all for $0.14/ea., but shipping will cost you. I ordered 6, which should cover any more mishaps for the time being. I asked for the part number, but not the size. Having gotten a few spares, I thought I might try to source some from the local Home Depot, as yet TBD.

A few days later I opened up a 424mkIII for another reason & discovered a totally redesigned tape mech, with no idler roller/clutch at all. FF/RW on this unit is another belt & gear driven assembly. OT/FYI.

:spank::eek:;)
 
Good to know about the C-rings, I cannot stress how careful I was to not let that thing fly away when I was replacing the tires. All went well, but next time I ever have to put in an order with TASCAM I will definitely throw a number of them in the cart for good measure.

I haven't had to take the 424MkIII apart yet, but did see some instructions on here from a while back. Are those other belts as "easily" replaceable as the 244/246 belts out of curiosity?
 
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