Tascam 388 & 238

[radiokake]

I have two problems :

a 238 with a highspeed running capstan motor, i plug it in, and it runs faster & faster. I have read that it 99% is fixable by changing some components on the motor board? Any tips?

a 388 with a slow rewind, someone said it was possible to adjut the breaks, or change the belt. Anyone know any service tech in Norway that could help me with this two machines?

Greetings from A.M.

 

[technoplayer]

The slow rewind on the 388 might be a simple servo adjustment. On either side of the headstack is a movable roller that works as part of the tape tensioning system. These are servo linked and work to control the reel motor speed in all modes. Try this: with the 388 in rewind, GENTLY push the left hand tensioner down (toward the control panel, not down like vertical). Also try the right hand tensioner the same way. If the tape speeds up, then there is an adjustment you can make to re-position the tension arm and thus regulate the rewind speed. Rather then explain the adjustment now, try this diagnostic first then I can fo into more detail.

 

[radiokake]

Thanks, I will check this out. -a.m.

 

[shedshrine]

I have a 238 with a highspeed running capstan motor, . I have read that it 99% is fixable by changing some components on the motor board? Any tips?

Below, same basic Tascam motor from the MK deck series, same issue..

http://thesquarewaveparade.com/tascam122.html

"there is a common problem with the tascam 122mkii (and other mk's) , after a certain age the motors start running really frigging fast, to the point of being completely useless. anyone that has ever had this issue has more then likely contacted tascam and received a replay saying that a motor replacement will cost over $80. ridiculous, but some people have done it several times because this is a really nice deck. others have just pitched them out or sold them cheap ($10 off of craigslist a long time ago) that think they can figure out what’s wrong with them. i've searched and asked but never found a single person that could tell me what's actually wrong with these things. clearly the motor is not toast or if would not work at all or it would work erratically or something. so a while later and several leaps forward in electronics knowledge i understood that the motor is actually controlled by pulse width modulation, ahhh... there is an oscillator that tells it how fast to go, and nearly ever oscillator i know of is dependant on a capacitor to determine its range. well some old caps fail after about 20 years of constant use, give or take, and most fail closed, meaning their capacitance will diminish to the point of them becoming the equivalent of a jumper (often causing problems shorting the rails to ground in the power section of older gear too). when the caps capacitance begins to decrease in value it will force the pitch / rate to increase causing the motor to speed up. soooo.... if you replace the timing cap (or caps in this case) it will theoretically restore the motors speed control to the factory rate and kill the chipmunks living in your wonderful and at one point incredibly expensive tape deck. "







more on the 238 and its issues..

http://messageboard.tapeop.com/viewtopic.php?t=42311&start=45

 

[technoplayer]

Shedshine:
Good info!!!
I have inquired in the past about a speed issue on my Tascam 112 cassette deck, and never gotten any info. It runs maybe 10% fast, but if I turn on the Varispeed, it spools up like crazy. Is this possibly the same sort of circuitry issue??

 

[shedshrine]

I built myself a dual pre Hamptone once, but my electronics skills are pretty neanderthal poke n' prod. (sweetbeats is my idol) But having read that article several times, if you have the tools and technique to rebuild your deck's motor, odds are good you'd probably fix your speed issue right up..

"when the caps capacitance begins to decrease in value it will force the pitch / rate to increase causing the motor to speed up. soooo.... if you replace the timing cap (or caps in this case) it will theoretically restore the motors speed control to the factory rate"

 

[sweetbeats]

Positive rep to you, shed, for putting that info up on the Tascam cassette servo board. That is potentially incredibly helpful for many.

And thanks for the nice word, but just to be clear my electronics skills are kind of like my typing skills. I still hunt 'n' peck, but I can do it really fast, and many times now can do it without looking at the keyboard but I never learned the proper fingers to use. So, skilled (just by virtue of experience and lots of mistakes), but still just poke 'n' prod.

Nice gear has fallen prey to my hammer mechanic approach (evm1024's Tascam 58 is probably the pinnacle example...nearly worthless pile of parts after my poking and prodding and now ready for the races in his hands), and many a kind soul hath pulled out their hair to teach/help me...I talk a good talk.

 

[technoplayer]

Now all I need is a schematic on the 112 .......not the MK models, just a plain ol' 112.

Anyone??

 

[radiokake]

Hi again,

so i tested this, and by holding the left roller down (towards the panel) it speeds up! Thats great, nothings broken (and the new belt i ordered from ebay can rest)

So - adjustment procedure, is it complex?

-a.m.

 

[radiokake]

adjustments on the 388

The slow rewind on the 388 might be a simple servo adjustment. On either side of the headstack is a movable roller that works as part of the tape tensioning system. These are servo linked and work to control the reel motor speed in all modes. Try this: with the 388 in rewind, GENTLY push the left hand tensioner down (toward the control panel, not down like vertical). Also try the right hand tensioner the same way. If the tape speeds up, then there is an adjustment you can make to re-position the tension arm and thus regulate the rewind speed. Rather then explain the adjustment now, try this diagnostic first then I can fo into more detail.

(original message)

 

[Erockrazor]

Thanks for your reply in my other post. This too for me has helped me out. (what technoplayer wrote)

If you own the manual, it goes into detail on page 1-9 but I'm still not positive the exact adjustment to be made. I'll fill you in with any findings.

 

[technoplayer]

Sorry I dont have access to my manual right now. I did cover this is a previous thread, so you could find it with a sarch on the forum. I will try to get back with you soon on this adjustment

 

[Erockrazor]

Copied from my post in another thread. Hope it helps!




Okay, so I was able to fix the problem.

For me the process went as follows:

Reel Servo Tension Roller Adjustment

The following process CAN help/cure playback, fast forward, and rewind issues on your Tascam 388. A simple adjustment to the Reel Servo "knobs" can adjust how your tape machine does these functions.

Step 1: First, power on your 388. Take off top cover of 388, behind the VU meters and above the in's and out's. Do it gently as to not harm your pride and joy.

Step 2: After cover removal, find the section of about 8 "knobs". They are above the tape window in a vertical orientation. They don't look exactly like "knobs" but that's why I'm putting quotations around it. If anyone can inform me the technical name for it, please do!

Step 3: Press play on your tape recorder.

Step 4: While tape is in motion, find the "knobs" named R 112 and R 212. These are the adjusters for the Tension Rollers.

A Reel Person's suggested Tension Roller orientation.

"The centers of the tension rollers should be even with an imaginary line that's drawn and extends from the BOTTOM EDGE of the capstan and idler rollers."

For me, my tension rollers worked best a little lower than A Reel Person's suggestion.

Step 5: Watch the adjustments made to your rollers. Try playback fast forward and rewind. Work until you find an adjustment where everything is working well.

Step 6: Feel great about yourself because; no, it's not a dead motor, no, it's not the end of your 388, and yes, you just fixed your most prized recording possession.

The beauty of this DIY fix up, is that you can't really screw up your 388 in the process if you just stick to the aforementioned process. It's all mechanical and you can fiddle until it works up to your standard. Another positive thing, is that none of this altered my play/record speed and that's the most important thing on this board!

Now go record something!!!!!!

 

[technoplayer]

Erock....Thanks for chiming in.
Here are a few snapshots from the manual which may help locate the necessary trim pots (thats what they are .called).

R112 adjusts the left hand tension arm.
R212 adjusts the right hand tension arm.

Before you adjust ANYTHING>>>>>> if you can
1) use a PLASTIC flat blade scewdriver or cover a metal one with tape. This will minimize you chances of shorting something out if your hand slips. Remember you are working on equipment with power applied!!!
2) Note the position of each pot BEFORE you make any adjustment.
3) adjust SLOWLY and in small increments. No need to crank the adjustment like you are screwing it in. A very small turn ought to do it.

 

[radiokake]

Allright! Thanks a lot!
I will try to make these adjustments. (And it's a great thing that almost nothing can get fuxxed in the process) Brilliant! -a.m.

 

[radiokake]

Thanks a lot to all the people who help me out (shedshrine, technoplayer, sweetbeats +++) 388 up and running, cleaned and adjusted. A very smooth machine, nice and easy to get a good sound on bass, casio mt65, ukulele, vocals (drums a bit harder to get down right,but i'll get it soon) great sound, good preamps. One can fall completley in love when looking at this machine. So.. - ready to do the session for Yoyoyo Acapulco's next album up in the Norwegian mountainside during week 29.

-a.m.