1967 Teac A-4010S Reel to Reel Restoration

[@mjg263]

Very interesting, I’ve worked on a number of these decks over the years and I’ve never run across one with that little playback amp in the mechanical section. They made so many variations on this deck while keeping the same 4010S model number so I guess one really has to go by the amplifier model number.

[@mguess]

I think this is a fairly early version of the A-4010S. The playback head amp allows you to use the upper part of the tape deck for playback only without the lower record amp connected. I think the unit was actually sold as a playback only deck without the record amp. I eventually discovered the source of the intermittent noise in the playback amp. It turned out to be a bad resistor. Here is a link to the video where I fixed it. kzbin.info/www/bejne/m53FdYVujLaBmNk

[@invictusbp1prop143]

Damn I wish KZbin were around back when my pops threw his Teac exactly like that one away because he couldn't keep it running anymore. I would have held onto it for sure if is known he as getting rid of it. So many memories of when I was little hearing that thing kick on on Sunday mornings while mom cleaned the house singing along with the Beatles blaring thru the big wood cabinet speakers with wooden grilles on the fronts. Those things were LOUD for back then. I Still smell lemon Pledge when I see one of these things... Still remember specific reels he used that he'd recorded off of the armed forces radio when we lived over seas after he came back from Vietnam. Oh btw, im pretty sure every original owner of those units was. a smoker back on the day. Lol!

[@mguess]

Thanks for sharing your memories of the old Teac. Very descriptive, I could almost see it playing at your childhood home. If you want to relive your childhood and are up for a restoration project, there are still many of those old Teac open reel machines for sale on ebay.

[@The8TrackChap]

That's late '60s and the early revision with PNP germanium transistors. Later revisions don't have the same transistors or the playback amplifier inside the deck. The two upper micro switches behind the faceplate are also gone on later ones, as well as the patch cables in the rear.

[@wesmoore1682]

It appears to have a mechanical relay to switch heads for the reverse direction. If the relay is noisey, that could also be part of the problem. Rapidly switching direction might help.

[@mguess]

Thanks for the comments. I did eventually find the cause of the intermittent noise. It turned out to be a bad resistor in the head amp circuit. Here is a link to the repair video. kzbin.info/www/bejne/m53FdYVujLaBmNk

[@MICHIGANROCKSANDROLL]

i have worked on a few Teacs. You have the left side threaded wrong. There is also a allen key on the reel tables buried behind to set reel table height.

[@MICHIGANROCKSANDROLL]

Just got to your discovery of the Allen key.

[@MICHIGANROCKSANDROLL]

Never understand how all the youtube repair people do not try the weakest link first. Clean and demagnetize, Clean switched and pots. Then dig deeper. I think that's a bad transistor that white noise. I got that from 12voltvideo.

[@mguess]

@@MICHIGANROCKSANDROLL I originally thought it was a noisy transistor. After replacing all the transistors and capacitors on the head preamp the noise temporarily went away but eventually returned. I eventually found a resistor in the driver transistor emitter circuit that was breaking down when it got warm. I replaced the resistor and now the noise problem is permanently fixed. Here is a link to that video. kzbin.info/www/bejne/m53FdYVujLaBmNk I also fixed the fast tape latching problem. Here is a link to that video. kzbin.info/www/bejne/mXatp2Wubt-BidU

[@MICHIGANROCKSANDROLL]

@@mguess Permanent? No such thing.

[@MICHIGANROCKSANDROLL]

@@mguess Pretty good video. May have to watch more.

[@juanbanzai]

I watched your video at a perfect time as I started restoring a 4010S that I inherited from a family member. Mine had many of the same issues yours did including the noisy output. Unfortunately, your video was a CLIFFHANGER when it came to the replacement of the transistors. Would you mind telling me if the NTE102 were a directly replacement for the 2SB486 on the preamp board, and if so, how did the unit sound after you made the replacement? I wish you’d do a part 2 to your video!

[@mguess]

Sorry for the cliffhanger. I ended up replacing all the transistors on the preamp board with NTE equivalents. All the replacement transistors worked well and sounded good. Unfortunately I never completely eliminated the noise problem. It is very intermittent now so hard to troubleshoot. I also never fixed the fast tape motion latch issue. You are correct, I need to do a "Part 2". Maybe I'll start working on that since there's not much on the bench right now. Let me know if you find your noise problem and what fixes it.

[@juanbanzai]

@@mguess I sure will. And thanks so much for getting back to me. If I may ask, did you replace the 2SB486 transistors or the 2SB189… or both. I always thought the 486s were the output transistors.

[@mguess]

I replaced both. The 2SB189 is the output transistor.

[@SDsailor7]

​@@mguessSo you replaced the 2SB189 output transistors withe the NTE102A? Thank you

[@DonBonin]

Thank you for sharing your work! I am on the path right now with a unit I'm trying to fix for a friend. Your schematic looks quite clean and readable - would you be willing to post it here? The PDF's I've found are badly compressed and some part values are compressed into blurry blobs of pixels... Thanks!

[@mguess]

If you want to give me your email address, I'll forward you the scans of the schematics from my copy of the original manual that came with the tape recorder.

[@DonBonin]

@@mguess thank you, that would be extremely helpful! [e-mail]

[@SDsailor7]

@@mguess I like that the boards are removable much easier to work on them. Good job on the rtr. Cheers

[@SDsailor7]

​@@mguessHow did you remove the amplifier board from the chassy? I have one screw at the bottom right side is covered by the plastic backing that goes around the cable inputs and power cable? I need to replace the capacitors on mine. Thank you

[@jamiebravo6550]

Hi, i recently acquired a teac a4010s (ar40s). Previous owner kept it in a closet for decades. It does not have the 2 silver screws on top of the cabinet like yours, do you know what year it was made? i Change both belts, lube and deoxit. Every lights and meters working. Sounds really good. Do i need to replace the capacitors? its working and sound great thanks.

[@mguess]

Mine is from 1967. I wouldn't change the capacitors if it's working ok.

[@jamiebravo6550]

@@mguess thank you sir! Playing old christmas carols

[@SDsailor7]

​@@mguessOn my 4010s I have to turn the line level and the playback level all the way to 3 o'clock to raise the volume to a listenable level so I think the playback amplifier board needs recapping.

[@SDsailor7]

​@@mguessI wish you would have showed how to remove the amplifier board from the chassy. I need to do the same.

[@SDsailor7]

​@@mguessSounds like the transistors are shot on the amplifier board due to the noise it's making.

[@langston1aladdin]

where did you get your repair Manuel? I have a copy of it that I got off the internet, but your looks like an original and is larger and easier to read. - Sorry, I read a bit further down and saw the same question. Whould it be possible for you to email to me also? Thanks.

[@mguess]

I'd be happy to send you what I have. Just send me your email address.

[@SDsailor7]

I removed the reel table to install the counter belt, it was not hard.

[@mguess]

Thanks for the input. I probably should have done that also rather than struggling to push the belt around the reel table.

[@SDsailor7]

@@mguess I noticed that you had the belt on the front of the flywheel (smaller section of the flywheel) and on Jordan Pier video he had it on the back (the larger section of the flywwheel) did yours operate correctly at the proper speed? also where did you put the other end? on the smaller section or the larger?(the small pulley). Thank you