The Tascam 238 rocks.

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repeat
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Tascam 238 maintenance

Post by repeat » Tue Nov 20, 2012 8:21 am

First post here, hi everyone... Maybe not really a 238 specific question but, since I just got one of these in nearly perfect shape and I'd like to keep it that way, I thought I'd ask here (plus it's not discussed on this thread yet)

In people's experience, just how essential is it to demagnetize the heads, and how often? Is it more of an issue with reel-to-reels, or should a regular degaussing routine be observed with a cassette machine as well? (Yes, I'm new to analog tape) I'm finding wildly differing opinions on various message boards, and also a bit worried as the operation seems to be slightly risky, especially with less than ideal tools.

I'm in Europe and I haven't really found a good Euro alternative to the oft-touted Han-D-Mag - some people recommend this thing but I really don't like the look of it, looks very clumsy plus it has both of the things people keep warning about (no rubber shielding, on/off switch). I fear there's more risk of fucking up the deck with that thing than with just regular head cleaning every session and forgetting about the demag. Any opinions?

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Post by The Scum » Tue Nov 20, 2012 9:40 am

My opinion is that demagging is overrated, and is often a scapegoat when something else is wrong. Magnetism is invisible and most people only have a vague notion of what it really is, so it seems somewhat magical.

That said, if the tape path is magnetized, that's a problem, and it needs to be fixed.

If you have a magnetization problem, the deck will erase the high end off tape that's passing through it. This happens noticeably faster than the gradual HF decay that you get from just running the tape...it falls off in a number of passes, rather than over days or weeks.

You're right in thinking it carries some risk, too. Done incorrectly, you can magenetize things far worse than they do by themselves.

RB Annis sell a kit with a demagger and a magnetometer, so you can measure for a field before you start to demag. Address the problem, not just the symptoms.

There's a pretty good youtube video of Fletcher doing the demag dance that would be worth watching if you're curious. Fletcher and Scott Dorsey have a more primary information than your average internet guy.
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repeat
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Post by repeat » Tue Nov 20, 2012 1:39 pm

Thanks, that's good to know - especially the symptoms of magnetization so I'll know to react if that starts happening. I'll definitely be cleaning the heads and tape path between sessions, so maybe there's no need for the daily magnetic rituals... The magnetometer sounds like a handy tool to have around in any case

Another thing I remember reading somewhere was rewinding a new tape back and forth a couple of times to shake off any loose oxide particles, then cleaning the tape path before starting to record - would anyone recommend that? It kind of makes sense, but sounds like all that rewinding might wear out the transport quicker than necessary...

I'm sorry about these dumb newbie questions but I'm really set on getting the best out of this deck so I don't want to mess it up right off the bat!

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Post by banana brains » Fri Feb 28, 2014 6:59 pm

Bought a 238S about one year ago. Had the capstan speed issue. Took it to a guy, guy had it for almost a year. Finally finished it. He tried recapping it. Didn't work. He said a few components were out of spec. Can't remember what he called them. (resisters maybe?) Problem solved.

He aligned it too. Looking forward to picking it up. Now I have to get a mixer.

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SMT CAP VALUES

Post by boriscrispin » Thu Mar 06, 2014 2:35 am

Image

Hey guys
old thread here but, guess what - a lousy ebayer pretended that the 238 (not 238s) he was selling me worked. But of course, it's making the jet engine noise and playing like a chipmunk

I'd like to know, is this a jpeg of the correct cap values for the 238?
I can't help but noticed the name of the image suggests its the tascam 122....

http://i24.photobucket.com/albums/c48/s ... iagram.jpg

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Post by shedshrine » Thu Mar 06, 2014 8:15 am

8 track cassette capstan motor tascam 238 syncaset

"The 238 and other 8 track and high quality stereo tape decks, the 688 and 122 MkII and III, used a direct drive capstan motor for precise speed control and reduced speed variation or wow and flutter (w/f). The circuit that controls this motor fails in certain ways causing lack of speed control and in our case the capstan motor wizzing away at a crazy speed, not the 9.5 cm/sec that it should do."

---------------------------------------------------------

http://www.gearslutz.com/board/low-end- ... motor.html

see Riffster58's post at bottom of thread for Tascam 238 capstan motor install bulletin pdf attachment
Last edited by shedshrine on Thu Mar 06, 2014 8:28 am, edited 1 time in total.

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boriscrispin
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Post by boriscrispin » Thu Mar 06, 2014 8:21 am

Hoorah!
I can't wait til this thing works.....

Has anyone ever had the desire or inclination to balanced the inputs? Surely that'd be nice/possible?

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boriscrispin
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Post by boriscrispin » Fri Mar 21, 2014 10:39 am

Darn it....so replaced the possible problem CAPS and it the jet-noise went and it appeared to playing normally,now five minutes in and it's playing a little too fast,
not crazily like before........any one have any ideas?

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Post by honkyjonk » Sat Mar 22, 2014 8:27 am

That does look exactly like my tascam 122mKIII capstan board. I know because I just replaced all those caps. It's quite likely that Tascam used the same motor and board for the 238 though.

Somebody on ebay had idler tires for cheap, of all kinds of tascam cassette machines. Here's a good thread about maintenance to a 122mKIII http://www.tapeheads.net/showthread.php?t=28736

getting at that idler tire in there is a bit of a bitch. Just be careful and go slow. Since there's no belts to replace (assuming this is similar to the 122) the other maintenance things to do is grease the gears and oil the capstan motor. See that post for more info.

You could try cleaning and exercising the variable speed switch too.
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boriscrispin
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Post by boriscrispin » Mon Mar 24, 2014 6:00 am

Ah well the 238 is a direct drive machine...!

The problem with mine being that it seems to take a long time for the machine to get to a level speed, for the first while its slow, then it speeds up over (quite a long) time and I have no idea if it eventually levels out to being the correct 9.5cm/s.....anyone else had this kind of issue?

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Post by vvv » Mon Mar 24, 2014 9:56 am

boriscrispin wrote:Ah well the 238 is a direct drive machine...!
Mebbe I'm misunderstanding you, but I'm sure my 238 was a belt drive. I can't recall ever seeing a direct drive multi-track cassette tape machine, if by "direct drive" you mean the motor is or is geared to the capstan (as in direct-drive turntable vs. belt drive.)
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boriscrispin
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Post by boriscrispin » Mon Mar 24, 2014 10:02 am

I assure you, it is direct-drive!

"The 238 capstan is a precision direct-drive design controlled
by an FG servo system that guarantees
unvarying speed and torque stability at the
238's 9.5 cm/second (3-3/4 ips)tape speed"

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Post by vvv » Mon Mar 24, 2014 11:51 am

Damn! :oops:

I remember I hadda replace a belt on it, mebbe it was just for the counter ...

Been a few years and a lotta martoonies, sorry!
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Post by Orpheus » Tue May 20, 2014 11:03 am

boriscrispin wrote:Hoorah!
I can't wait til this thing works.....

Has anyone ever had the desire or inclination to balanced the inputs? Surely that'd be nice/possible?
You would likely have to do that externally. I cant see a way to cram the circuitry inside the chassis.

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Post by standup » Tue Jun 17, 2014 7:40 pm

boriscrispin wrote:Hoorah!
I can't wait til this thing works.....

Has anyone ever had the desire or inclination to balanced the inputs? Surely that'd be nice/possible?
I've got a Fostex 8 channel RCA to XLR balanced/unbalanced converter box. Look for something like that, can't recall the model number and it's not here right now. External boxes for balancing equipment like this were easy to find in the 80's/90/s.

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