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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 10th Oct 2023, 11:52 am   #1
EF80TVVALVE
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Default EMI TR52/2D Tape Recorder

Hi Everyone

As I posted in a wanted thread, I have been tasked with repairing this EMI tape recorder. It was found buried with a huge amount of various cine, audio, video and other electrical equipment in a garage and the first photos show the condition in which it found it's way to me in. I've spent many hours cleaning the unit and a tin of brasso and some cloth has improved the paint finish greatly.

I'm now moving onto the mechanical and electrical components of the unit, I did bring it up slowly over some time and there seems to be some life from the monitor speaker but I've been unable to play any tape as of yet. Upon inspection this unit looks to be ex-RAF and was in use until 1977 at least.

The first problem I have to solve is the rubber drive coupler that is mounted between the motor shaft and flywheel. That is to say that this unit has no direct metal to metal drive from the motor and all movement is transferred by this rubber suspension. As can be seen it has split and the rubber is degrading very badly. I have read on one site about an owner using inner tube rubber to build a new one so I will probably go down the same route. There's nothing particularly special about it's construction so I'll just need to be sure that it turns true to avoid any uneven rotation. Has anybody on the forum undertaken such a job before?

Other than that the rest is in good order and I'd imagine restoration will be straightforward, this isn't a machine I've worked on before and I'm quite impressed by the build quality, I hope the final results are just as good!
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Old 25th Jan 2024, 11:40 pm   #2
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Default Re: EMI TR52/2D Tape Recorder

I've spent some time on overcoming the problem with the decaying coupling rubber for the motor drive. After taking the two pieces of rubber apart I found that the condition wasn't too bad and the tearing were just small isolated spots of dryness combined with force from the motor which had caused the damage.

I did consider re-creating the two rubber discs and making a new rubber coupler from scratch but after some deliberation I decided to buy a good size sheet of tyre repair rubber and (after making good the original rubber pieces) used this as an extra layer over the originals to support and strengthen them.

At the moment I'm still very slowly adhering the two rubber pieces together but so far it all looks like it should work very well once finished. Once all of that is done I can start stripping and cleaning up the tape deck, giving it a good grease too as its quite seized.

I'm still after a cover for the heads and the carry case too if anybody comes across any, it would be nice to get it all complete again.
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Old 27th Jan 2024, 7:34 am   #3
barrymagrec
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Default Re: EMI TR52/2D Tape Recorder

The bellows coupling acts as a low pass mechanical filter to reduce motor flutter being transmitted to the capstan, so try and make sure your repair doesn`t make the coupling too stiff.

I have a vague memory that the D variant had different equalisation for instrumentation use but I may be wrong about that.
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Old 27th Jan 2024, 11:01 am   #4
EF80TVVALVE
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Default Re: EMI TR52/2D Tape Recorder

I did take the transfer of flutter into consideration when choosing a suitable material, the over-layered rubber I have chosen is very thin and hopefully hasn't added too much firmness to the part. Once it's all back together I'm quite happy to dismantle and start again should that be necessary. I plan to take it into work once finished as we have suitable equipment there to measure flutter but fingers crossed this repair will be sufficient.
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Old 7th Feb 2024, 5:23 pm   #5
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Default Re: EMI TR52/2D Tape Recorder

Well the TR52 is all back together. It's taken quite a lot of work to get it to actually play anything. The capstan was quite well seized so some stripping and cleaning of the mechanism was undertaken though only enough to get it working. Once I'm happy with it then I'll undertake a more thorough clean and service of the deck.

The tape recorder now works very well and safe to say that my repair to the coupler looks to be a success judging from, so far, only a listen. I found some previous recorded 15ips and 7.5ips tapes and played them, the playback was superb. I need to source a test tape with suitable frequency recordings so that I can critically measure the wow and flutter, I don't expect it to be identical to the given EMI data, I doubt many even left the factory that good but it would be nice to know how close it is and how well my repair of the drive coupling is.
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Old 7th Feb 2024, 5:45 pm   #6
Ted Kendall
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Default Re: EMI TR52/2D Tape Recorder

The coupler was a bit of an Achilles' heel on this transport - the TR51, which used the same deck, was rendered by some engineers as the "TR fifty-waaaaahn" in imitation of the sheep-like flutter which could develop with wear. Still, if it's going right, good on you.
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Old 7th Feb 2024, 6:41 pm   #7
barrymagrec
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Default Re: EMI TR52/2D Tape Recorder

I suspect the coupling was of fairly variable quality at different times,it`s not a particularly clever design in the first place.

Having said that flutter was never a problem on my (Dad`s) TR50 when I was playing with it back in the mid sixties, although since it was a 3.75 / 7.5ips model I almost always ran it at 7.5 ips where the higher motor speed would have helped. It was also fitted with a new coupling at that time due to the original having perished in poor storage conditions.

Congratulations on making it work.

The original machine, if it was for audio rather than data would have used the old CCIR 100us characteristic at 7.5ips so you would need to allow for a slight top boost when playing a modern 70us test tape. The 35us characteristic at 15ips is the same for both standards.
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Old 8th Feb 2024, 10:49 am   #8
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Default Re: EMI TR52/2D Tape Recorder

Yes it makes you wonder how many of these machines are in use with a coupler driving the mechanism by barely a thread! I did search far and wide to find anything online of somebody rebuilding one but I didn't come up with anything. It will be interesting to see how well it runs in actual figures though but as I said previously, I don't expect it to be as good as EMI states especially after 60 years.

I still hope to complete it by finding a carry case and head cover. I know a lot of these machines have been broken up for the modules so fingers crossed some spares will turn up at some point. I'm just glad that I've managed to save one as I think it a shame that such a well designed and built machine is often gutted out for the sake of its amplifiers, mind you that can be said for many of these items nowadays.
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Old 8th Feb 2024, 11:27 am   #9
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Default Re: EMI TR52/2D Tape Recorder

I think I have some head covers but they are from a TR50 and a TR51 so I`m not sure the cutouts at the back are the same, also they are green and yours looks to be ministry grey / blue, which indicates it was actually an RE 301 and had an aluminium case.
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Old 8th Feb 2024, 12:42 pm   #10
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Default Re: EMI TR52/2D Tape Recorder

The RE301 was the heaviest tape recorder I ever encountered!

I believe the 'backwards' running takeup spool was supposed to reduce flutter, but Studer etc didn't seem to have a problem...
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Old 8th Feb 2024, 12:49 pm   #11
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Default Re: EMI TR52/2D Tape Recorder

One from a TR51 may indeed fit, it has the appropriate holes for the cue and also the track selector which, in the case of the TR51 is the speed selector, other than the wording being different there they look virtually identical.

Perhaps the photos of my machine are a trick of the light, mine is a pale green colour and is marked as a TR52/2D on the little plastic plate.
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Old 8th Feb 2024, 12:50 pm   #12
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Default Re: EMI TR52/2D Tape Recorder

WD40, the TR52 I have weighs an absolute ton, they are back breaking machines. I think I read somewhere online that they're around 35kg, there is a lot of solid, thick metal in the build of them so it doesn't surprise me.
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Old 8th Feb 2024, 1:17 pm   #13
barrymagrec
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Default Re: EMI TR52/2D Tape Recorder

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Originally Posted by wd40addict View Post
The RE301 was the heaviest tape recorder I ever encountered!

I believe the 'backwards' running takeup spool was supposed to reduce flutter, but Studer etc didn't seem to have a problem...
There were no rigid standards for A / B wind back in the very early fifties when the deck was designed, the original EMI BTR1 was B wind (oxide out) the BTR2 of 1953 was A wind.

Print through was a problem in the early days and it was suggested that storing the tape oxide out would reduce this, possibly because of the pre print would be less than the post print (or something like that)

In my opinion the B wind take up spool was a mechanical convenience, it eliminated the need for an extra idler for the take up drive and there was no downside with the TR50 and original HMV versions being full track only.

When 1/2 track versions of the TR51 and HMV machines were offered they added the Chrome roller to aid twisting the tape so the reel could be turned over, pointless in my opinion as you lost the 8 1/4 inch spool facility and I used to twist the tape straight off the pinch roller with no problems after I fitted a 1/2 track head to the TR50.

I can see no reason for the wind direction to affect flutter in any way.
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Old 8th Feb 2024, 1:19 pm   #14
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Default Re: EMI TR52/2D Tape Recorder

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Originally Posted by EF80TVVALVE View Post
One from a TR51 may indeed fit, it has the appropriate holes for the cue and also the track selector which, in the case of the TR51 is the speed selector, other than the wording being different there they look virtually identical.

Perhaps the photos of my machine are a trick of the light, mine is a pale green colour and is marked as a TR52/2D on the little plastic plate.
I1ll have a look in my loft and see if I have a cover that you could use.
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Old 8th Feb 2024, 1:55 pm   #15
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Default Re: EMI TR52/2D Tape Recorder

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In my opinion the B wind take up spool was a mechanical convenience, it eliminated the need for an extra idler for the take up drive and there was no downside with the TR50 and original HMV versions being full track only.
That was my suspicion too. Sometimes design compromises are justified as features. Hammond Organ was also pretty good at this.
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Old 8th Feb 2024, 2:53 pm   #16
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Default Re: EMI TR52/2D Tape Recorder

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There were no rigid standards for A / B wind back in the very early fifties when the deck was designed, the original EMI BTR1 was B wind (oxide out) the BTR2 of 1953 was A wind.
The original Ampex 200 was oxide out; about a year after it was introduced a 201 adaptor kit was produced, with new amplifiers equalised for the new NAB standard instead of the arbitrary curves previously used, and a new headblock for A-wind.

There was also an early Philips domestic machine which had a clockwise feed spool and an anti-clockwise take-up spool.
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Old 9th Feb 2024, 12:21 pm   #17
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Default Re: EMI TR52/2D Tape Recorder

Thanks Barry, that would be a great help if you come across one! Did the TR50 and TR51 use the same type of rubber coupler? I'm very much new to these EMI machines really, I didn't even know of their existence until this TR52 came my way, the only ones I'd ever seen were the smaller portables used for field work (L2) and, of course, their large studio types.
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Old 9th Feb 2024, 3:54 pm   #18
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Default Re: EMI TR52/2D Tape Recorder

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There was also an early Philips domestic machine which had a clockwise feed spool and an anti-clockwise take-up spool.
I have a (non-working) Philips EL3540 / 3545 which uses that configuration.
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Old 9th Feb 2024, 7:45 pm   #19
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Default Re: EMI TR52/2D Tape Recorder

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Originally Posted by EF80TVVALVE View Post
Thanks Barry, that would be a great help if you come across one! Did the TR50 and TR51 use the same type of rubber coupler? I'm very much new to these EMI machines really, I didn't even know of their existence until this TR52 came my way, the only ones I'd ever seen were the smaller portables used for field work (L2) and, of course, their large studio types.
This deck was used by EMI for over a decade - it first appeared in the Emicorda and the 3031 tape players which launched with the mono pre-recorded tapes in 1954. It appeared the following year in the enormous 3034, a pair of coffins for playing Stereosonic tapes and LPs.
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Old 11th Feb 2024, 1:02 pm   #20
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Default Re: EMI TR52/2D Tape Recorder

Yes, I believe it was first used in the TR50 in 1952 and subsequently in the TR51, TR52 and RE301 on the professional side and as you say a raft of consumer models. I think the capstan coupling was the same throughout but the motor on the consumer machines was different, as they were single speed.

I have had a look in my loft and found a TR51 head cover pair, unfortunately the main cover is quite battered though it could possibly be improved, I think the cut outs are correct but obviously the lettering is wrong. I also have a TR50 main cover in much better condition but it has no cut out for the cueing arm.

Other fascinating things I had forgotten about include a serviceable belt and a NOS coupling which looks to be perfect despite being 71 years old. I`m pleased about this as when I last looked the belt on my HMV3031 was badly perished and the coupling is not likely to be much good either.

Also many other odds and ends including a complete unused headblock for a TR50 and a replay / record switch assembly for the amplifier.

And should you want a capstan / flywheel assembly for a MIDAS flight recorder replay system.......
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