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DIY TEAC auto reverse foil alternatives

Adinol

Adinol

Member
I just performed a belt change and lube of my old TEAC A-4010S.

I never got to use the auto reverse feature so I looked on eBay for the foil and found nothing.

Then I Googled "DIY TEAC auto reverse foil alternatives" and also found nothing, not even on this forum.

Does anyone know of any DIY auto reverse foil alternatives?

Thanks...
 
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When I got an 8-track player, I soon learned that one of the things I had to become adept at was repairing the cartridges. 8 tracks use a foil splice to trigger the player to switch to playing the next of the four stereo programs after it finishes playing one of them. With very old, worn cartridges those splices have often come apart. I bought a roll of 2" wide foil tape from the heating department of the hardware store. I cut little tape splice pieces from this material that work just fine. I expect the same material would work for reversing R2R tapes.
 
All I can say about the HVAC tape is that I didn't have adhesive ooze during application and that the splices I made were not sticky. When I first learned to splice 1/4" R2R tape in the 1960s or 70s, I remember that the splicing tape I bought at electronics stores often made sticky splices no matter how careful I was. I'm not sure that the HVAC tape I used is much thicker than the kinds of splicing tape I have seen and used, though it might be. When I found that it seemed to make good splices, what I have actually worried the most about was whether the bending involved with traveling through the tape path would cause it to break, since it was intended for use in which it would be stuck on something that would not be flexing.
 
illinoisteve said:
All I can say about the HVAC tape is that I didn't have adhesive ooze during application and that the splices I made were not sticky...
Click to expand...

I guess it also boils down to the inevitable fact that there are many types of tape. Some tapes meant for electronics might be bad and some HVAC tapes might be suitable for this application, even if they were never intended to be used as such. The HVAC tape that I happen to have around the house is very thick and obviously not suitable, but that doesn't mean there can't be another brand that might be OK to use.
 
Adinol said:
How long should the sensing foil be? 2" seems quite long and I was thinking more along the lines of 3/4". But what's the standard?
Click to expand...

I think this depends on the characteristics of the auto-reversing system. In most cases the aluminum auto-reverse tape is used to connect two contact points which triggers the auto-reverse system to change direction. The distance between these two contact points determines the minimum length of auto-reverse tape that can be used and allow the system to operate properly. On my Teac X-1000R this distance is approximately 3/4” and I usually use a 1” length of auto-reverse tape to provide some safety margin.
 
8-track carts run at 3 3/4 ips, so 1" of tape gives just under a 1/4 second "pulse" for activation.
Broadcast carts and mainstream open reel pre-recorded music tapes are at 7.5 ips, so your "pulse" duration will be half that of 8-track. 15 ips follows suit. I've not seen a 30 ips auto-reverse machine... So, how long the sensing foil needs to be depends on how responsive the individual deck's circuitry is. When in doubt, do what the manual says as your first attempt.

On edit, after reading above simul-post: I don't have an auto reverse machine; didn't realize contacts were that far apart. I guess I was thinking they're about 1/4" or less apart. Machine must 'lock out' triggering after first hit, otherwise deck would sit there and reverse itself into dust. Or, it goes into reverse play so fast that it happens while sensing tape is still in full contact, so logic resets when contacts are no longer bridged.

All this is why I like accurate autolocators...

Chip
 
Chip - I’m not sure how other auto-reverse decks operate but on the Teac X-1000R and also on the Pioneer RT-909 the auto-reverse tape only switches from forward play to reverse play, not from reverse to forward play. The switch from reverse play to forward play occurs when the tape counter reaches zero (assuming continuous play mode is selected). This avoids the problem of repetitive reversals that you mentioned.

The comment you made about the duration of the signal that triggers auto-reverse being different based on tape speed is certainly correct which is another reason why I indicated that the length of auto-reverse tape required for proper operation depends on the characteristics of the auto-reversing system.
 
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The Hvac tape I used does seem thick, until you peal the paper backing off of it, which accounts for most of the thickness.
 
illinoisteve said:
The Hvac tape I used does seem thick, until you peal the paper backing off of it, which accounts for most of the thickness.
Click to expand...

To be perfectly honest, I don't even know what the thickness of the proper sensing foil is as I've never seen it. My HVAC foil (without it's backing) feels thicker than the audio tape. Or perhaps it just feels that way as it is a stiffer material. I also think that it's likely that the layer of glue on HVAC foils is probably thicker than the glue layer on audio foils, which is probably the main reason why the glue could ooze. I went to my basement and looked at pipes that were wrapped about 10 years ago. I can't see any oozing there. Arguably, I'm looking at extreme circumstances with a lot of thermal expansion, unlike anything that audio tapes should ever be subject to. So, if there's no oozing after 10 years will there be any after 50 years? I think it is more unlikely we'll see oozing after the glue has already been drying for 10 years.

The other questions is, will a HVAC hack (no pun intended) stand the test of time?

Well, let's take a step back. Did the approved sensing foils stand the test of time? From what I'm learning, it seems that a lot of 8-track tapes need to be repaired. So, it seems they did not stand the test of time.

I personally don't like spending $20 for something that could cost me .20c. I'm sure that all audio sensing foils are not equal and neither are all HVAC foils. But there is the possibility that there are some HVAC foils that work just fine, that do not ooze and that might even surpass some of the official audio foils with regards to the test of time. illinoisteve says that his HVAC hack did stand the test of time.

I'm sure some of the audio foils are simply overpriced and it really depends on the project, if it makes sense to pay the price. I'm not sure if I would risk doing the HVAC hack on an expensive collector's reel (but perhaps I wouldn't even risk using the real foil on such reel) but in my particular case I am just trying to put a sensing foil on some cheap reels that my 7-year old kid is using. That said, and since I haven't ordered the real foil yet, I think I'll just go with the same hack that illinoisteve says served him well for years. I'm sure the tapes will not be ruined.

Thanks...
 
I've been using the real metal furnace tape for years. I see that now Menards has this in two thicknesses, the thinner stuff is probably the best for this. No problems with the Teac deck or on 8 track tapes. When I put this on a reel tape I also put a small strip on the plastic reel to remind me that the tape will reverse. Note that there is also plastic tape that looks like metal, obviously it won't work.
 
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