RegisterRegister
Log in to check your private messagesLog in to check your private messages
Log inLog in
FAQ  -  SEARCH  -  MEMBERS  -  FAVORITES  -  PROFILE
Tascam 238 Needs Alignment - Any Good Techs/Service Centers?

 
Post new topic   Reply to topic   printer-friendly view    Tape Op Message Board Forum Index -> Gear Talk
View previous topic :: View next topic  
Author Message
0wl
studio intern


Joined: 14 Jan 2016
Posts: 29
Location: Detroit, MI (Okay, I live in the Suburbs)

PostPosted: Tue Feb 21, 2017 8:47 pm    Post subject: Tascam 238 Needs Alignment - Any Good Techs/Service Centers? Reply with quote

I've got a Tascam 238 8-track cassette recorder that was outfitted with a new TEAC motor/capstan assembly a few years ago. It sounds great and seems to work smoothly, but of course with 8 tracks crammed on such a narrow medium, there seem to be some head alignment problems.

For instance, I'll record stereo to tracks 4 and 5. During recording, the 238s meters indicate that both tracks are equally loud (the meters top out at roughly the same spot). But then when I play the tracks back, one of them will be much louder than the other, and the meter will also be much higher.

Is this in fact a head alignment problem?

If so, does anybody know of a good tech or service location that could align the heads to my particular model of cassette? I live in Michigan but am willing to ship it out if there's a good tech elsewhere in the US. I've been on the Tascam website and called a few authorized service locations, but many of them either seem unfamiliar with the machine, are extremely expensive and/or unprofessional, or have 3+ months of backup.

I'm beginning to rely more and more on this machine (to the point where I'm considering investing in a second one to use a backup), so It'd be nice to find a decent tech who has some experience with similar units. Ideally if I end up buying a second 238 I'd like to send both to the same reputable person who can identically align them so tapes will play properly across both machines.

Thanks in advance!
Back to top
View user's profile Send private message
floid
re-cappin' neve


Joined: 03 Jan 2006
Posts: 736
Location: in exile

PostPosted: Tue Feb 21, 2017 10:52 pm    Post subject: Re: Tascam 238 Needs Alignment - Any Good Techs/Service Centers? Reply with quote

First,
Do you clean the headstack and transport on a regular basis? Dirty heads can cause these type effects.
How do the heads look? Worn heads can do the same.
Does this happen with a brand new cassette? What length cassette do you use? Stretched/ curled tape from overuse or thin stock (90min and up, usually) is another likely suspect.
Have you confirmed level in/out per track? As in, recording a test tone at a certain meter level and comparing this to the playback level. Are you getting less level out than you put in? On all tracks or just some? Is the difference consistent?
What happens when you record test tones and then flip the tape: does the problem follow the changed track order (a record issue) or remain on the same channel (a playback issue)?
Barring dirty/worn heads or bad tape, I would suspect a problem in the record and playback circuits before the heads themselves. I never tried anything like this on my 238 when I had it, but have discovered my Teac and Tascam open face machines aren't that difficult to work on. Sometimes the solution is as simple as pulling a card, hitting it with some canned air, and reseating it. Or you might find the service manual and see if there is a basic calibration you can do involving something like "playback level trimpot adjust." Just be sure you make minor adjustments at a time and know how far you've gone from the initial settings so you can return to them if need be.
_________________
Village Idiot.
Back to top
View user's profile Send private message
jimjazzdad
ass engineer


Joined: 19 Jan 2012
Posts: 49
Location: Halifax, NS, Canada

PostPosted: Wed Feb 22, 2017 12:35 pm    Post subject: Re: Tascam 238 Needs Alignment - Any Good Techs/Service Centers? Reply with quote

I'm a R2R guy, not cassette, but everything Floid says is good advice. Try heading over to the Tapeheads site - lots of techs and knowledgeable folks there.
_________________
Jim Legere
Halifax, NS
Canada
Back to top
View user's profile Send private message
0wl
studio intern


Joined: 14 Jan 2016
Posts: 29
Location: Detroit, MI (Okay, I live in the Suburbs)

PostPosted: Thu Feb 23, 2017 4:39 am    Post subject: Re: Tascam 238 Needs Alignment - Any Good Techs/Service Centers? Reply with quote

I appreciate all the good advice, floid. I did record my voice on all 8 tracks and played them all back when I first bought the machine, but haven't done anything too scientific since then. But to eliminate a few potential issues you suggested:

I clean the heads and pinch roller thoroughly w/ q-tips and rubbing alcohol before and after every recording session. I'm not entirely sure what worn heads look like, but to me these look shiny and new. And I always use new or new-ish Maxell XLII 60 minute cassettes, so old or stretched tape is probably out as well.

When I get a chance I'll be sure to record a test tone (would a drone from a keyboard work?) on all the tracks and try to get a more accurate diagnostic of the problem, as per your latter suggestions (flipping the tape, etc).

I'll report back with everything I find and then think about how to proceed.

And jim, I appreciate the tapeheads suggestion too. I might just copy the OP from this thread and see if I can get some help over there.

Thanks again all!
Back to top
View user's profile Send private message
0wl
studio intern


Joined: 14 Jan 2016
Posts: 29
Location: Detroit, MI (Okay, I live in the Suburbs)

PostPosted: Fri Feb 24, 2017 12:50 am    Post subject: Re: Tascam 238 Needs Alignment - Any Good Techs/Service Centers? Reply with quote

I went ahead and recorded a basic tone from a synthesizer, on all 8 tracks, one by one. Each time during recording I made sure the meter topped out at the +3db mark. Upon playback, here are the results:

Track 1: +3db (proper)
Track 2: -3db (low)
Track 3: -3db (low)
Track 4: -3db (low)
Track 5: +5db (high)
Track 6: -3b (low)
Track 7: -1db (low)
Track 8: -7db (very low)

Actual volume levels (according to my ear) do in fact correspond with the meter values. For instance Track 5 was noticeably louder and Track 8 was noticeably quieter, even without looking at the meters.

And I'm not totally sure if I'm understanding you right when you say to flip the tape, but I tried flipping it over to Side B and there is no sound at all. I listened all the way through the tape and there's nothing.
Back to top
View user's profile Send private message
floid
re-cappin' neve


Joined: 03 Jan 2006
Posts: 736
Location: in exile

PostPosted: Fri Feb 24, 2017 11:50 am    Post subject: Re: Tascam 238 Needs Alignment - Any Good Techs/Service Centers? Reply with quote

Hmm, perhaps i'm misremembering which cassette deck I did backwards noodling on. No reverse playback must be to do with the offset heads and track spacing.
Looking at page 5 of the owner's manual, it should be possible make a crude test tape by recording tones at a known level on a standard deck and use this to check playback on channels 1,2,7,8. But it would take a proper tape from Gennlab or similar to confirm and adjust playback on all channels. The playback section needs to be done before calibrating the record section.
_________________
Village Idiot.
Back to top
View user's profile Send private message
A.David.MacKinnon
mixes from purgatory


Joined: 07 May 2003
Posts: 2909
Location: Toronto

PostPosted: Fri Feb 24, 2017 1:56 pm    Post subject: Re: Tascam 238 Needs Alignment - Any Good Techs/Service Centers? Reply with quote

The playback readings would lead me to suspect that the head or heads are out of alignment. Is there heavy cross talk between channels on playback? if you stripe a tone on 1 does it also show up on 2 when you hit play? If that's ok try striping tone on 8 and looking for bleed on 7. That would indicate that the head(s) aren't properly in line. If that's ok then it's probably just a calibration issue. It's well worth getting a real tone tape and learning to calibrate the machine. There are some great youtube tutorials out there for reel to reel. The process is the same for cassette with a few minor alterations.

One last thing never ever, ever, ever, ever use alcohol on the roller or any other rubber parts. It'll dry them out. Alcohol for metal, soap and water for rubber.
_________________
Dave

http://adavidmackinnon.blogspot.com
http://adavidmackinnon.bandcamp.com
Back to top
View user's profile Send private message Visit poster's website
floid
re-cappin' neve


Joined: 03 Jan 2006
Posts: 736
Location: in exile

PostPosted: Fri Feb 24, 2017 4:35 pm    Post subject: Re: Tascam 238 Needs Alignment - Any Good Techs/Service Centers? Reply with quote

This is a "3 head" format only b/c it uses one dual purpose head for tracks 1-4 and another for 5-8. The tracks from each head are interleaved on tape. In addition to checking for crosstalk between heads (track 2 shows up on 5 or 6, for example), you could record an identitical simultaneous tone to tracks 1-4. Check output levels. Then record silence to tracks 5-8. Check output levels again. Repeat with reverse track orders. If signal decreases in either instance, the erase head might be misaligned with one or both heads.
_________________
Village Idiot.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic   printer-friendly view    Tape Op Message Board Forum Index -> Gear Talk All times are GMT - 4 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum