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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 15th May 2021, 3:35 pm   #1
Robashard
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Default EMI RE321 VU meter

I’ve been given a working EMI RE321 portable tape machine that records well, plays back low on itself but fine on another machine, and is in good cosmetic condition. However, its VU meter glass has gone, and I initially the thought the needle was broken. On closer inspection the needle was bent over double.

I have managed to unfold it but we had noticed that it also stopped half way across the scale and that’s still the case, but at the moment I can’t see what’s stopping it I notice that the top spring, pictured, seems mis-shaped, and it won’t pull the needle back, but this could be because it’s sticking. All terribly fiddly!

The details of the meter are on the scale plate. Does anyone have a movement like this that they’d sell me? Does anyone repair them (before I do any more damage!)?
Is anyone familiar with this machine? There doesn’t seem to be a playback volume pot, which seems a little strange. I’ve obtained a circuit diagram and can’t see one on there.
Interesting machine. Full video of it coming to life for the first time since 1972 on Facebook Ooen Reel Tape Machines group
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Old 15th May 2021, 5:13 pm   #2
barrymagrec
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Default Re: EMI RE321 VU meter

The meter on these machines was 50uA and very fragile, particularly with age. It is the same as on the earlier valve model L2.

The speaker amplifier was only a pair of OC72s so they probably didn`t think it would go loud enough to need a volume control but I think there is a preset beside the battery box.

I have the instruction manual for this machine which I could probably scan for you if you only have the circuit.
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Old 16th May 2021, 7:00 pm   #3
Robashard
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Default Re: EMI RE321 VU meter

That’s very kind Barry. I did find a manual on eBay, but in the US, and he wouldn’t ship! However, a friend over there has bought it. It’s not arrived at his yet, but he will send it on, and scan any other crucial bits.
But if that doesn’t work out, can I give you a shout?
Rob
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Old 16th May 2021, 7:12 pm   #4
Robashard
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Default Re: EMI RE321 VU meter

Funnily enough, I only noticed that preset pot in the battery compartment the other day. However, for the life of me, I can’t see it on the circuit diagram on the top block, which is the replay section, and so, coupled with the fact that it’s a preset without a knob, I’d wondered if it was the Bias pot.
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Old 17th May 2021, 6:50 am   #5
barrymagrec
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Default Re: EMI RE321 VU meter

Quote:
Originally Posted by Robashard View Post
Funnily enough, I only noticed that preset pot in the battery compartment the other day. However, for the life of me, I can’t see it on the circuit diagram on the top block, which is the replay section, and so, coupled with the fact that it’s a preset without a knob, I’d wondered if it was the Bias pot.
It is on the circuit but it`s on the interconnection diagram which you may not yet have (In the manual it`s on the reverse of the amplifier drawing). It`s not very obvious even there.

I don`t have personal experience of working on the RE321 but slight knowledge of the L2.
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Old 18th May 2021, 9:10 pm   #6
Stevie342000
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Default Re: EMI RE321 VU meter

You will find the schematic in here RD4 left hand side: http://www.bbceng.info/ti/tis-post-1949.htm

I think it is full and it was originally a BBC design - there should be schematics and manuals if you do a search as I have the same machine. They sell on eBay (can never remember if this is one of the forums I can mention the name or not) or have done recently for a few £100 I got mine a few years back for £1.50, it cost me a day trip to Richmond to pick it up from Manchester. It was summer and I walked through Richmond Park from something or other Common on the District Line....it was a long walk and a lovely day.
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Old 19th May 2021, 1:06 pm   #7
barrymagrec
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Default Re: EMI RE321 VU meter

That is a fascinating set of information - the documentation on early Leevers Rich machines is more detailed than I ever saw at the factory.

I had heard that the RE321 was a BBC design but could never understand why - EMI had the expertise to transistorise the L2 themselves if they had wished. I also heard they were noisy compared with the valve machine, a check of the specification suggests that it was very carefully written.
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Old 19th May 2021, 2:40 pm   #8
knobtwiddler
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Default Re: EMI RE321 VU meter

At an AES lecture a few yrs back, I heard a funny story pertaining to a 'EMI' portable cutting lathe used by the BBC. A well-known historian was perplexed, as he never realised EMI had made such a machine. He tracked down its owner, who'd used it during WW2, whilst at the Beeb.

On seeing said machine, it became immediately apparent that the lathe was not designed or made by EMI... It was actually a Neumann, that had been rebranded as 'EMI' during the war -)
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