Teac A-4070g worth repairing?

moonstation2

New Member
I've had this Teac 4070 for maybe 15 years now. A month or so ago I hooked it up to a mixer (incorrectly) to record something and I ended up with a pop and some smoke and a blown fuse.

I took it to an electronics guy to get repaired and he got it running again but the tape speed function is shot. It's stuck on low speed so I can't play pre-recorded tapes and plenty of my own tapes. If I can get a new speed selector switch then I can have this unit running again.

My question is should I try to find a switch and repair this? Or is the 4070 worth it? Should I abandon this unit and get a different model reel to reel?
 
I like the idea of redundancy when it comes to vintage gear. These decks are old and they need repair from time to time. So I would be inclined to find another machine. I would probably keep the 4070 for repair when I could find the part. Working machines are a little easier to sell, but even non-working are sought after by people on the Bay, at the right price.
 
I guess that's a good idea, I can get another machine, then keep searching for the part on ebay until one pops up.

I guess my question was more along the lines of whether or not this unit is a good candidate for upkeep, or am I throwing money at a bad/outdated/breakdown prone reel to reel when I should just go out and purchase "x" reel to reel that would be worth fixing when it breaks.

I don't know very much about this particular model and haven't been able to discover much by searching.
 
The 4070 is a pretty complicated and trouble prone model as TEAC open reel decks go. It's a great tape deck when it's all sorted out and working properly but repair and upkeep on that particular model can be a real challenge due to its complicated nature. If all you need is a good basic 7" machine without bi-directional record and all the other bells and whistles I'd keep an eye out for a good old TEAC A-2300S or SX. They usually need some basic pinch roller linkage repair and other minor stuff but they are very straightforward to repair and quite reliable. I'd keep the 4070 but I don't think I'd sink a bunch of money into it.
 
When my 4070 needed a part I waited for someone to part one out on eBay. He didn't list the part I needed, so I asked him if he had it. I remember paying him $9 for it.

It's a great machine when you get it running right. The only problem I've had since I went through it is when it fell over and cracked the dust cover in an earthquake.

It is more complicated and harder to work on than the SX series I'm used to, but I got through it.
 
I've had this Teac 4070 for maybe 15 years now. A month or so ago I hooked it up to a mixer (incorrectly) to record something and I ended up with a pop and some smoke and a blown fuse.

I took it to an electronics guy to get repaired and he got it running again but the tape speed function is shot. It's stuck on low speed so I can't play pre-recorded tapes and plenty of my own tapes. If I can get a new speed selector switch then I can have this unit running again.

My question is should I try to find a switch and repair this? Or is the 4070 worth it? Should I abandon this unit and get a different model reel to reel?
I came across your post about the speed problem with your deck. I too have a 4070, and years ago the belt needed replacing, which was done, but when I got it back the speed ran a touch too FAST, repair shop said there was nothing they could do about that (guess they didn't know what they were talking about) so I put it away. Recently thought about trying to get it back running again and I see your post about the "speed selector" switch. I was told there was some diode or something that emitted a signal to keep the speed correct. SO did you ever get yours repaired. Thanks,
Mike
 
There isn’t anything that isn’t repairable, you just need to find a tech who really understands TEAC R2R’s and has the experience to undertake the work. Ask Sam Palermo on here for his advise publicly or if you prefer, he accepts PM’s.
 
Greetings from RojoLand!

The touch-too-fast speed could be caused by the belt being on the 50 Hz pulleys, if you're in a 60-Hz country like USA or Canada. The capstan motor and flywheel each have two pulley surfaces. For 60 Hz, the belt should be on the smaller motor pulley.

My understanding is that being stuck on one speed can be caused by shorted snubber caps in some models. Not sure on this A-4070 — it appears to have the newer capacitor-and-resistor snubbers (shown on the schematic like this: —< >— instead of the usual capacitor —| |— ). Is your machine a plain A-4070 or later A-4070G?

Take care,

J. E. Knox "The Victor Freak"
 
There isn’t anything that isn’t repairable, you just need to find a tech who really understands TEAC R2R’s and has the experience to undertake the work. Ask Sam Palermo on here for his advise publicly or if you prefer, he accepts PM’s.
Thanks for the info
 
Greetings from RojoLand!

The touch-too-fast speed could be caused by the belt being on the 50 Hz pulleys, if you're in a 60-Hz country like USA or Canada. The capstan motor and flywheel each have two pulley surfaces. For 60 Hz, the belt should be on the smaller motor pulley.

My understanding is that being stuck on one speed can be caused by shorted snubber caps in some models. Not sure on this A-4070 — it appears to have the newer capacitor-and-resistor snubbers (shown on the schematic like this: —< >— instead of the usual capacitor —| |— ). Is your machine a plain A-4070 or later A-4070G?

Take care,

J. E. Knox "The Victor Freak"
Its the "G" and I would have to open it up to check those pulleys. The belt was replaced by a supposedly good outfit
 
The TEAC A-4070 has, on the back of it, a switch (sometimes a lever that pushes/pulls the switch) that changes the 'bias' to either 50 or 60 hz. Changing that hz bias changes the tape speed slightly and can audibly be heard during playback cause the tape will speed up or slow down slightly while switching. If that lever or switch is not there it has been incorrectly covered up by some previous user and can be seen inside the box . The inside can be reached by simply removing 2 screws and sliding the insides forward. And yes that bias switch causes the capstan belt to mechanically move over to a different size pulley as was stated in a previous post. It is a fantastic sounding unit. After hearing playback from a good recorded reel you will marvel at the quality sound it outputs.
A new belt can be had for about 15$ on Ebay. That belt can be put on by removing 4 screws from the back of the inside frame, scooting the large softball size wheel forward a half inch, putting on the belt, replacing the screws which will put the wheel back in place (now with the new belt on it). Unit is definitely worth saving and the belt change is a breeze.
 
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