Problems with Tascam Teac 38 tape machine. - UK Vintage Radio Repair and Restoration Discussion Forum

thosetapes · 15th Dec 2008, 6:34 pm

I have a Tascam Teac 38 and I have some problems with recording and playback.

Some of the tracks will record but play back really muffled, quietly and under a layer of noise.Ii got a demagnetizer and it cleared up most, but I still have problems with 3 tracks.

The meters show signals. I believe my dB levels are good. Any suggestions? I'm awaiting a couple of new snakes, but so far it doesn't seem to be cables.

julie_m · 15th Dec 2008, 7:31 pm

The symptoms you describe sound like classic dirty record / playback heads.

Have you cleaned the heads with a suitable solvent -- methylated spirits or isopropanol ?

It may take several goes to get them clean.

Nickthedentist · 15th Dec 2008, 7:36 pm

Quote:

Originally Posted by ajs_derby

The symptoms you describe sound like classic dirty record / playback heads.

...possibly because your tapes are shedding oxide (search for "sticky shed" on the forum)

thosetapes · 22nd Jan 2009, 5:02 am

Sorry for taking a bit to get back on here.

I have cleaned the lot with IPA and I have demagnetized.

I actually got new snakes and a new mixer since I was away from the internet. Playing what I've recorded sounds better through reproduce output (also will play back a couple channels that sync function won't play back. What does that mean?).

The noise cleared up, but now just the first track won't playback, but shows in the meter when recording. If it was alignment would it be the same for other tracks?

I am investigating getting meters, scopes, alignment tape, etc. Should I rush into all that equipment with the problem I have? Maybe its the VU meter pot? even though I have had problems, I love it. Truly is a craft.

arjoll · 22nd Jan 2009, 10:26 am

Clean the heads again. Also clean all the switches - I use CRC CO to clean then CRC 2.26 to lubricate but these are AU/NZ products. Other users will be able to recommend alternatives.

I've only got the 32 service manual but haven't checked it. If no one has access to the 38 service manual I'll have a look (its probably very similar, just four times as many channels), but suspect that if you have playback in repro but nothing in sync then it will almost certainly be switching. If sync is there but muffled then you're cleaning heads again.

thosetapes · 23rd Jan 2009, 4:44 am

So... clean the circuitry of the switches? ok, I have the manual, and so far I have yet to find anything about it. I've been digging everywhere. I've got to find someone local who knows more about it.

I'll let you know how I make out... thanks for the help!!!!

techladuk · 29th Jan 2009, 7:53 am

If you've cleaned the heads and it's not fixed the problem? Sounds possibly like REC or REPRO heads misalignment or wear, or tape tension too low.

Are the tracks that are affected at the outside edge of the tape? ie tracks 1-3 faulty 2-8 ok or tracks 8-6 faulty and 5-1 ok? If so its probably uneven wear of the head face, causing gap widening or failure, on either or both heads that's causing the problem.

I used to do a lot of Pro Audio maintenance and servicing in the 80's. Used to see quite a few lower cost/semipro 1/2" 1/4" multitrack machines that had that uneven head wear problems, especially if they had been hammered in a demo studio with no maintenance staff!

The REC/SYNC head and REPRO heads have to be aligned accurately both individually and to each other. If the head "Zenith" (that's the tilt of the head vertically, front to back as you look directly at the head face) is not adjusted so the head face is exactly in the same vertical plane as the tape wants to travel one end of the head will wear faster than the other. Not usually a problem with new heads but as the face wears down each track core may have a different depth some less than others causing random tracks to fail due to gap widening.

In a machine that has heads that are nearly beyond repair, sometimes it's possible to correct for uneven wear by increasing the tape tension to compensate by forcing the tape tight against the heads, but doing so will increase the wear rate and hasten total head failure!

If the heads are suffering uneven wear pattens some times a relap can help rescue but only if they are not too far gone already.

post some pics of the heads if you can, problems with wear can be obvious if you know what to look for

TIP: When buying a tape machine - ALWAYS examine the heads or ask for a good close-up picture if you can't actually see the machine before buying. Heads are expensive to replace and sometimes impossible to get!

15th Dec 2008, 6:34 pm	#1
thosetapes Retired Dormant Member Join Date: Dec 2008 Location: boston, massachusetts usa Posts: 3	Problems with Tascam Teac 38 tape machine. I have a Tascam Teac 38 and I have some problems with recording and playback. Some of the tracks will record but play back really muffled, quietly and under a layer of noise.Ii got a demagnetizer and it cleared up most, but I still have problems with 3 tracks. The meters show signals. I believe my dB levels are good. Any suggestions? I'm awaiting a couple of new snakes, but so far it doesn't seem to be cables. Last edited by Brian R Pateman; 15th Dec 2008 at 6:37 pm. Reason: FSK problem fixed.

15th Dec 2008, 7:31 pm	#2
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Problems with Tascam Teac 38 tape machine. The symptoms you describe sound like classic dirty record / playback heads. Have you cleaned the heads with a suitable solvent -- methylated spirits or isopropanol ? It may take several goes to get them clean. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

22nd Jan 2009, 5:02 am	#4
thosetapes Retired Dormant Member Join Date: Dec 2008 Location: boston, massachusetts usa Posts: 3	Re: Problems with Tascam Teac 38 tape machine. Sorry for taking a bit to get back on here. I have cleaned the lot with IPA and I have demagnetized. I actually got new snakes and a new mixer since I was away from the internet. Playing what I've recorded sounds better through reproduce output (also will play back a couple channels that sync function won't play back. What does that mean?). The noise cleared up, but now just the first track won't playback, but shows in the meter when recording. If it was alignment would it be the same for other tracks? I am investigating getting meters, scopes, alignment tape, etc. Should I rush into all that equipment with the problem I have? Maybe its the VU meter pot? even though I have had problems, I love it. Truly is a craft. Last edited by Darren-UK; 22nd Jan 2009 at 10:11 am. Reason: FSK problem fixed.

22nd Jan 2009, 10:26 am	#5
arjoll Dekatron Join Date: May 2006 Location: Invercargill, New Zealand Posts: 3,458	Re: Problems with Tascam Teac 38 tape machine. Clean the heads again. Also clean all the switches - I use CRC CO to clean then CRC 2.26 to lubricate but these are AU/NZ products. Other users will be able to recommend alternatives. I've only got the 32 service manual but haven't checked it. If no one has access to the 38 service manual I'll have a look (its probably very similar, just four times as many channels), but suspect that if you have playback in repro but nothing in sync then it will almost certainly be switching. If sync is there but muffled then you're cleaning heads again.

23rd Jan 2009, 4:44 am	#6
thosetapes Retired Dormant Member Join Date: Dec 2008 Location: boston, massachusetts usa Posts: 3	Re: Problems with Tascam Teac 38 tape machine. So... clean the circuitry of the switches? ok, I have the manual, and so far I have yet to find anything about it. I've been digging everywhere. I've got to find someone local who knows more about it. I'll let you know how I make out... thanks for the help!!!! Last edited by Darren-UK; 23rd Jan 2009 at 9:55 am. Reason: FSK problem fixed.

29th Jan 2009, 7:53 am	#7
techladuk Retired Dormant Member Join Date: Aug 2008 Location: Liverpool UK Posts: 2	Re: Problems with Tascam Teac 38 tape machine. If you've cleaned the heads and it's not fixed the problem? Sounds possibly like REC or REPRO heads misalignment or wear, or tape tension too low. Are the tracks that are affected at the outside edge of the tape? ie tracks 1-3 faulty 2-8 ok or tracks 8-6 faulty and 5-1 ok? If so its probably uneven wear of the head face, causing gap widening or failure, on either or both heads that's causing the problem. I used to do a lot of Pro Audio maintenance and servicing in the 80's. Used to see quite a few lower cost/semipro 1/2" 1/4" multitrack machines that had that uneven head wear problems, especially if they had been hammered in a demo studio with no maintenance staff! The REC/SYNC head and REPRO heads have to be aligned accurately both individually and to each other. If the head "Zenith" (that's the tilt of the head vertically, front to back as you look directly at the head face) is not adjusted so the head face is exactly in the same vertical plane as the tape wants to travel one end of the head will wear faster than the other. Not usually a problem with new heads but as the face wears down each track core may have a different depth some less than others causing random tracks to fail due to gap widening. In a machine that has heads that are nearly beyond repair, sometimes it's possible to correct for uneven wear by increasing the tape tension to compensate by forcing the tape tight against the heads, but doing so will increase the wear rate and hasten total head failure! If the heads are suffering uneven wear pattens some times a relap can help rescue but only if they are not too far gone already. post some pics of the heads if you can, problems with wear can be obvious if you know what to look for TIP: When buying a tape machine - ALWAYS examine the heads or ask for a good close-up picture if you can't actually see the machine before buying. Heads are expensive to replace and sometimes impossible to get!