tascam 688 - disassembly and (hopefully) repair)

Hi, hopefully you're still around.. i'm having a hard time getting the arm rest off from unit. it happened to me years ago with another same unit model and i ended up braking section of arm rest. I'm not sure about 5 screws you mentioned. I have loosened them up but still not releasing arm rest. I greatly appreciate your advise.

Thanks,

Gus
 
I realize that this is an old thread...but, the info here is fantastic..I have on of these units to repair for somebody...I believe it is belt issues...Hopefully I can find one.....
 
Hey, Heatmizer: I don't know if you are still following this. I had a 688 in my closet since 2002, and pulled it out last week, and through my googling on repairs, I found your thread, and I want to thank you for your photos and post. It helped me tremendously and saved me a major repair. I found some belts on Ebay, and followed your post. My belt not only had broken, but apparently twisted around the plastic rotor on the capstan motor, and it all melted to a tarry goop on the capstan motor and rotor. After about 3-4 hours of careful cleaning, I got all parts like new, even the capstan motor. I was extra careful cleaning the goop off the motor, and the center axle itself. I was afraid it had gotten inside. Use sewing maching oil, it is so quiet now. Belt, flywheel, motor all work great now. I also found another thread about changing out the battery so I did that, too. Not easy, and I had to repair a ground wire I broke off, but it all seems to be working fine now, thanks to your and the other thread. Thanks again, and also to Ely. I am a "silver fox" as they say, but not to old to learn new tricks, and I can get back to recording like I used to. The repair place I was going to take it to had a min. $100 charge just to look at it, non-refundable. This post saved me easily $3-400 in charges. M
 
mich19498 said:
Hey, Heatmizer: I don't know if you are still following this. I had a 688 in my closet since 2002, and pulled it out last week, and through my googling on repairs, I found your thread, and I want to thank you for your photos and post. It helped me tremendously and saved me a major repair. I found some belts on Ebay, and followed your post. My belt not only had broken, but apparently twisted around the plastic rotor on the capstan motor, and it all melted to a tarry goop on the capstan motor and rotor. After about 3-4 hours of careful cleaning, I got all parts like new, even the capstan motor. I was extra careful cleaning the goop off the motor, and the center axle itself. I was afraid it had gotten inside. Use sewing maching oil, it is so quiet now. Belt, flywheel, motor all work great now. I also found another thread about changing out the battery so I did that, too. Not easy, and I had to repair a ground wire I broke off, but it all seems to be working fine now, thanks to your and the other thread. Thanks again, and also to Ely. I am a "silver fox" as they say, but not to old to learn new tricks, and I can get back to recording like I used to. The repair place I was going to take it to had a min. $100 charge just to look at it, non-refundable. This post saved me easily $3-400 in charges. M
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I also have one of these to repair for a friend....I have also used these pics in order to repair it...But I still have another problem.....The motor runs very fast and the variable speed control does not slow it down....I have searched the net for schematics but couldn't find any....Does anybody here on this forum have schematics or some idea of what the problem would be??
Cheers
 
688 motor runs faster than typical cassette.

bsco said:
I also have one of these to repair for a friend....I have also used these pics in order to repair it...But I still have another problem.....The motor runs very fast and the variable speed control does not slow it down....I have searched the net for schematics but couldn't find any....Does anybody here on this forum have schematics or some idea of what the problem would be??
Cheers
Click to expand...

The capstan motor always runs, and it runs faster than a typical cassette deck. For example, I am using some TDK High Bias cassettes to record, and they are SM 20 which means 20 min total, or, 10 min on one side. But the Tascam runs about 2x faster, so I only get about 5 min of recording time, which is fine for what I am doing now.

I keep it on the fixed speed. Be sure to use a good sewing machine oil, but don't drown it. ALso look for the other rewind motor, and any small gears that might benefit from a small drop of oil, but don't be messy. Also, the two little screws fastening the tape drive to the plastic cover are very important, they keep it aligned with the plastic cover. I used both Tascam tape head remover+que tips for cleaning the capstan motor, and also Windex (suggested by someone here) and it really cleaned off the gummy tar off of the plastic rotor, flywheel. Oh, don't lose the tiny plastic washer if you take off the flywheel. Mine is running great. Good luck!
 
mich19498 said:
The capstan motor always runs, and it runs faster than a typical cassette deck. For example, I am using some TDK High Bias cassettes to record, and they are SM 20 which means 20 min total, or, 10 min on one side. But the Tascam runs about 2x faster, so I only get about 5 min of recording time, which is fine for what I am doing now.

I keep it on the fixed speed. Be sure to use a good sewing machine oil, but don't drown it. ALso look for the other rewind motor, and any small gears that might benefit from a small drop of oil, but don't be messy. Also, the two little screws fastening the tape drive to the plastic cover are very important, they keep it aligned with the plastic cover. I used both Tascam tape head remover+que tips for cleaning the capstan motor, and also Windex (suggested by someone here) and it really cleaned off the gummy tar off of the plastic rotor, flywheel. Oh, don't lose the tiny plastic washer if you take off the flywheel. Mine is running great. Good luck!
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Thanks for the reply.....I do realize that these multi track decks run much faster than normal cassette decks.....my issue is that the variable speed control doesn't do anything....and in order to have any chance of figuring out what is going on here a schematic would be very helpful.....I have searched the net and so far came up empty......I was hoping that somebody here on this forum might have one.....or have had the same problem.......I have replaced the belt and have cleaned up everything.....so I think it is an electronic problem......If anybody out there has a schematic for this unit please let me know......
Cheers
 
bsco said:
Thanks for the reply.....I do realize that these multi track decks run much faster than normal cassette decks.....my issue is that the variable speed control doesn't do anything....and in order to have any chance of figuring out what is going on here a schematic would be very helpful.....I have searched the net and so far came up empty......I was hoping that somebody here on this forum might have one.....or have had the same problem.......I have replaced the belt and have cleaned up everything.....so I think it is an electronic problem......If anybody out there has a schematic for this unit please let me know......
Cheers
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At the risk of being insulting(which I do NOT mean to be), did you select Variable speed with the switch, as opposed to Fixed?
M
 
Awesome thread! I'm guessing there's not much chance of an update given the lapse of time? Thanks all the same for posting as much as you did. Its all very helpful.
 
robertrichards said:
Awesome thread! I'm guessing there's not much chance of an update given the lapse of time? Thanks all the same for posting as much as you did. Its all very helpful.
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Hi there.....I had to replace the motor in the unit I had....it was running at max speed with no control....and it was a problem with the motor......
 
Thanks for the update mate, I have X2 238's and a midiizer and thinking about buying a 688 that is available to lock with one of the 238's (keep x1 238 as spare). Do you still use yours? Whats your opinion of the 688?
 
robertrichards said:
Thanks for the update mate, I have X2 238's and a midiizer and thinking about buying a 688 that is available to lock with one of the 238's (keep x1 238 as spare). Do you still use yours? Whats your opinion of the 688?
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I had to repair this for a friend of a friend......I did find it very complicated to use for the amount of time that I was playing around with it...The owner has had it for quite a while and he said the same thing....I guess it is like everything else...once you figure everything out and use it on a regular basis, the more comfortable you will be with it..get yourself a copy of the owner's manual and study it......personally I prefer an 8 track reel to reel..... but i have used cassette multi-tracks as well and have gotten amazing sounds out of them....the trick is to keep them squeaky clean....Hope this helps.....
Cheers,
Bernie
 
From what I can tell the 688 is mechanically the same as the 238 except for the 688 is driven by a belt where the 238 is direct drive, other than that the 688 seems to have taken the 8 track quality specs from the 238, some of the midiizer functions regarding midi and shoved it all into the portastudio format, which is awesome as long as it delivers. All the research I have done on the 688 is positive, there seems to be no production problems in the machine at all other than normal wear and tear. I don't have a question just thinking out-loud. Could be a handy little addition to my little home studio/edit suite setup.
 
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Hello there! I've scored pretty beaten up 688. Replaced belt. Track 4 doesn't respond to mute/ always on (annoying). I have problems with fader 7-8. It works only in tiny spot at unity gain, and it gets worse. Last week I coudn't even get to record anything to track 7-8 because of this fader. I've managed to get my head around cryptic routing system, so basically I can record quick. Even managed to slave hw midi sequencer to tape AS WELL AS Reaper (though audio tracjs seem to glitch).
What is a model/make/dimensions of master faders? Does deoxit/kotakt 60 cures my woes? Is it dirt, or is it dead carbon track
 
There are more qualified people here than me to answer those questions but Ill give it a go and hope others will jump in if I give wrong info. The fader sounds like it is dirty, if this is the case you could certainly try the spray cleaners but personally I wouldn't. Typically these cleaners remove gunk on the immediate contact which then gets shoved at either end of the fader...this isn't desirable especially on a recording console. In your shoes I would spring to get the fader replaced and get the tech to give it a good going over while he is at it. There should be a replacement fader that would fit it...may not be an OEM part though. Whilst these decks are well built and designed really well it is important to realise they are also 20 plus years old and possibly been laying in attics or garages for years before being sold off. So, its going to cost you some dosh but get it professionally sorted...and you'll have a great machine. Have fun mate :)
 
Updated! Tried kontakt 60, and it worked!
On the downside, i've discovered, that track 4 somehow spills into 1-3 tracks. It somehow getting worse. The whole routing for track 4 is not working (mute/line/mic/tape) - its just everything at the same time.
I guess there is some type of logic chip, controlling the gates for each track. And 4th went awol. Or electrilytic caps have dryed out.
Looking for sevice manual
 
ojd said:
Updated! Tried kontakt 60, and it worked!
On the downside, i've discovered, that track 4 somehow spills into 1-3 tracks. It somehow getting worse. The whole routing for track 4 is not working (mute/line/mic/tape) - its just everything at the same time.
I guess there is some type of logic chip, controlling the gates for each track. And 4th went awol. Or electrilytic caps have dryed out.
Looking for sevice manual
Click to expand...
You did say the cleaner fixed the problem with the fader...right??? Are the're any switches in the channel 4 strip?? (I don't own one of these machines) but you might want to spray any switches located in the strip....that could be part of your problem...If this thing has been in storage for awhile, you might be running into a few more of these sudden issues.......also, if the strip is removable, meaning that the strips plug into a motherboard or a connector board for example, then you could also have a contact problem there as well.....contact cleaner can also work here.......just use a good quality one.....don't use WD40......hope this helps somewhat......
 
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