Teac A4010S parts list

[hermitcrab]

I picked up another Teac R2R on the cheap, and after getting into it I see why ... another mouse hotel , chassis had nests and urine rust all over it ... cleaned it out and lubed it so the mechanics work as they should , currently working on the amp as only the right channel works , the left is dead , my thought was the head might be bad as I can inject a signal into the center of both volume controls and I get signal from both speakers... but I ruled out the head as this is a reverse playing deck which uses another head for the reverse play , and that one is also dead on the same channel so that is on going... but the issue I have is someone cut the record light bulbs out of it so I have no idea what it takes ... I have been told on other forums that the 4010 uses filament bulbs and the 4010s should use neon bulbs... and I cant check the supply to them as the record relay is not engaging , so that might be another issue , but HiFi engine manual has no parts list ... anyone on the forum have a parts list for this machine?
Thanks

[William]

Check you PM's, Elton.

Bill

[hermitcrab]

Thanks for looking Bill... I think I found an issue, this unit has a headphone amplifier and I lost the signal on the left channel there ... I got a 1/4" stereo jack somewhere ....just got to find it.

[TC Chris]

No tech info here, but much interest, as I've got an A4010S that's in the vast queue of someday projects. My victory on the Heath console will allow me to move on to other neglected orphans. I've also got an A1200U that hasn't been in service for 30 years, since I moved. So please share info on your project as it proceeds.

I have distinct memory from 1969. I was in Atlanta, being trained as a VISTA volunteer. The training center was in an old building downtown. At the end of the day, we'd all head out to grab a bus to the poor areas where we were housed with "sub-marginal poverty families." It was an eye-opener for Chris. But what I recall was getting out one day in October, when it was getting dark early, and walking to a Morrison Cafeteria (southerners will know about that) for dinner before busing "home" for the night. I passed a hi-fi shop with an A1200U in the window, and stood there gazing longingly at it. There's no special reason that this image stuck in my memory, but it did. Years later I found a used one.

Chris Campbell

[danrclem]

I remember when I was young and when RTR decks were big. I'd look at the ads and drool. Especially the ones with the big reels. They just looked so awesome. I have one deck that is fully functional and I can't remember the last time I used it. I'd like to have some good pre-recorded tapes just to see how good it would sound.

[William]

What brand is the deck you are referring to, Danny?

Bill

[hermitcrab]

obviously someone has been in here before seeing the lights were cut out... note the rust on the chassis ... even the knobs on the front were rusted on the shafts... might need to print some new ones , the 2 wires hanging out from the meter was the light bulb, they must be internally wired inside the meter, but even while the set is on , I cant find any voltage going to the back of the meters... only getting mV on my VOM... this one is a basket case .

[danrclem]

What brand is the deck you are referring to, Danny?

Bill

It's a Pioneer RT-909. I also have a Teac X-10R that I bought for the nab hub adapters. It's been awhile but if I remember right it played slow. I didn't give much more for it than the nab hub adapters would have cost and it came with a Teac cleaning/demagnetizing kit and several tapes. I also have a Roberts tube unit and another unit out in the garage. I'm thinking it is an Akai.

[William]

Wow, Danny, the RT909's were high end and are worth a lot of money now. They can take up to 10 reels. The Pioneer 707 decks are really excellent decks and are in high demand when you can find one. You are very lucky to have that 909.

Bill

[hermitcrab]

well I got confirmation that the rec lights are neon bulbs driven off the rec oscillator... but still no part number to cross to to replace them ... I am back to thinking the head is bad, the heads are tied together for FWD and REVERSE play and the left is dead both directions , I cleaned the relays and they were stuck , now I get a hiss on both channels when I press rec .... but if it turns out to be the head it will sit on the shelf until I can come across one

[William]

How did you determine that the bulbs are neon?

Bill

[TC Chris]

Neon bulbs usually have two electrodes and no filament.

Chi Campbell

[William]

But in Elton's case the bulbs were missing and he had no schematic so he would not know that. I looked at the sort of schematic that I have for my Teac A4010SL and the bulb showed to have a filament. Maybe in a schematic the bulbs look generic. I do not have a parts list to confirm anything.

Bill

[hermitcrab]

How did you determine that the bulbs are neon?

Bill

A member on audio karma said depending on the serial number as they made many changes during the years on the model ....any SN in the high 50's is going to be neon and this set the serial# is in the 90's and he sent me a schematic showing neon bulbs , I also have two different schematics for the same machine , even some of the caps in sections are different values on each schematic ... crazy... but no parts list to be had yet....

[hermitcrab]

Neon bulbs usually have two electrodes and no filament.

Chi Campbell

Chris you are correct, it shows neon symbols for the bulbs on the latest schematic I got... I have downloaded 3 different schematics so far , all slightly different, the early ones do show a filament symbol for the REC lights, the set I sold Bill A4010LS is the latest model , but his shows filaments again...

[William]

Maybe it was just the case of what was handy as they went down the assemble line. It is really odd that there is no parts list available.

Bill

[hermitcrab]

I really was thinking the head is open, if I check the plug from the heads that plugs into the board , the left shows open... the right reads about 250 ohms , but the way the machine is wired , when you reverse the playback and use the reverse head , it bypasses the left forward head so the left should play in reverse play , but it still does not and it is not open..the head switching is controlled by a relay, so I guess I will try cleaning the relay first before attacking the cable running to the board, which I might add is stiff and is not very flexible from age , I have been bending it every which way , I could have broke a wire internally?...it is a stupid setup , there is no access to the back of the heads without taking the whole assembly apart which is the last thing I want to do ... it would mean messing up the alignment on all 4 heads ...

[hermitcrab]

well the good news is the head is not open , I actually jumped the speaker to one of the preamp stages and I hear sound ,whew.... I found a manual for my serial # and it is great quality , but still a tad too small for me... so to enlarge the print... all these PDF sites want you to pay for that service...being the cheapskate I am , my workaround is enlarge the screen as much as possible, then take a picture of it then send it to the printer ...(see pic) I have found a few caps open , and now I am concentrating on the meter section as that is the final stage before the line output yet both meters are dead ... except on record , then they will swing ... nothing on the line out

[William]

It sounds like you are having fun and I am glad it is you and not me. R To R's are way above my pay grade, too many small things attached to printed circuit boards. Good luck, I hope you get it playing.

Bill