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Old 27th Nov 2007, 5:10 pm   #1
RobinBirch
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Default PCR Type differences

Hi,
Some further PCR questions. I have a PCR. I believe that it is a PCR 1 as it has a speaker built into it.

The audio stage is a 6V6 and there are several screened cables taped to one side as though they went to top caps that are no longer present. There is no evidence of circuit changes below the chassis and the ends of the cables are taped over professionally, as though they were done at manufacture.

Looking at the EMER that I have a copy of the PCR had an EL32 for the last valve stage and an inbuilt speaker whilst the PCR 1 had a 6V6 and, I assume, an in built speaker.

Is it possible that I have a set that was at least partly built to work with either valve setup or has someone been in and mucked about, even though they have done a very professional job of it.

CHeers

Robin
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Old 27th Nov 2007, 7:40 pm   #2
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Arrow Re: PCR Type differences

My researches came up with this lot . . .

Four variants of the PCR are known to exist: PCR, PCR1, PCR2 & PCR3. They have most features in common. It was designed to receive A.M. broadcast stations, so a BFO was not fitted.
This receiver first became available to the general public about 1961.

Summary.

Common Features:
Standard single-conversion superhet with 1 RF stage & 2 IF stages.
6 Octal valves; O/P stage = 6V6
Originally designed for an external PSU. (It was a very common modification for one to be fitted internally).
A 12-v. dc-input vibrator-type PSU was manufactured for these receivers.

PCR:
Tuning range: 850 - 2,000 metres; 200 - 550 metres; 6 - 18 MHz.
Contains an internal speaker.

PCR1:
Tuning range: 860 - 2,080 metres; 190 - 570 metres; 5.6 - 18 MHz.
Contains an internal speaker.

PCR2:
Tuning range: 850 - 2,000 metres; 200 - 550 metres; 6 - 23 MHz.
Does not contain an internal speaker.

PCR3:
Tuning range: 200 - 550 metres; 2.5 - 7 MHz; 7 - 23 MHz.
Does not contain an internal speaker.

The EL32 is not as per 'original spec.', but this - and the other items you mention - may well be a re-work by REME.

Hope that helps.

Al / Skywave.
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Old 27th Nov 2007, 8:36 pm   #3
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Default Re: PCR Type differences

To quote from "Wireless For The Warrior Volume 3":-

"The AF output valve is a VT52 in the PCR (PCR1) and a 6V6G in all later versions. A Philips or Mullard made valve type EL32 will be often found in lieu of the VT52 in the PCR (PCR1)"

A picture of a PCR-1 with a VT52/EL32 appears in the same book.

I scanned the pages of the book relating to the PCR for a forum member some time ago and will email them to anyone who wants them.
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Old 27th Nov 2007, 8:57 pm   #4
dave walsh
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Default Re: PCR Type differences

I've got two [in the North]. one will be a PCR by this definition. The other I've never really looked at very closely but I bought it at an Oldham Rally some years ago simply because not only was it in it's own case [rarely seen] but also it had attached the seperate PSU referred to [in a seperate case]. I'd definetely never seen one with a PSU before and I 've never seen a type numbering to take account of the addition or absence of this unit. I wrote to the bring and buy vendor but he couldn't tell me much except that it had been used in his workplace for years!
I previously ran the [uncased] PCR until the o/p stage expired.
Although primarily for am, as indicated, there were plenty of BFO mods in PW. I seem to remember that the SW range was fairly sensitive and that it would justify going to the trouble of adding one although I haven't tried that [yet]. Dave
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Old 27th Nov 2007, 9:04 pm   #5
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Thumbs up Re: PCR Type differences

Quote:
Originally Posted by Station X View Post
To quote from "Wireless For The Warrior Volume 3":-
"The AF output valve is a VT52 in the PCR (PCR1) and a 6V6G in all later versions. A Philips or Mullard made valve type EL32 will be often found in lieu of the VT52 in the PCR (PCR1)"
Thanks Graham - I stand enlightened.

Al / Skywave.
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Old 27th Nov 2007, 9:13 pm   #6
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Default Re: PCR Type differences

There were four different PSUs.

Supply Unit Vibratory No. 8.
Supply Unit Vibratory No. 9. (Tropicalised).
Supply Unit Rectifier No. 17.
Supply Unit Rectifier No.5

The latter was originally used for HRO receivers and PCR 3s had to be modified to use it, the resulting set being known as PCR 3 MK1/1.

There was also a PCR 3TPL aka PCR MK1/2.
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Old 27th Nov 2007, 9:57 pm   #7
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Default Re: PCR Type differences

Thanks for info Graham, I will look closely when I return to Lancs. Dave
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Old 27th Nov 2007, 10:37 pm   #8
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Default Re: PCR Type differences

These sets were thought to be Naafi sets but according to the latest information on the official history PYE radio site , they were in fact designed to be used in operations particularly after D day landings as a performance broadcast receiver to keep the troops up to date with the invasion progress. This is why their cases are essentially WS19 and can be strapped into the standard WS 19 metal armoured vehicle radio set carriers.

I always thought they were Naafi sets but never understood why they were so good on performance for this role.

This is the link to the Info of all the marks etc

http://www.pyetelecomhistory.org/pro..._Type_PCR_PCR2_
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Old 27th Nov 2007, 10:44 pm   #9
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Default Re: PCR Type differences

Forgot to mention that post war just like the WS19 sets the PCR service life was extended so there maybe modifications that you see in your set that will have been done by the REME. One of these mods I believe was the fitting of a power supply. Designed in 1944 they went out of service in early 60's .

"Overhauled to Class ‘B’ Standard 23 Base W.S. R.E.M.E. March 56"

is often stamped on units that have been modified

regards
Mike
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Old 27th Nov 2007, 11:54 pm   #10
dave walsh
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Default Re: PCR Type differences

Thanks Michael that does explain a lot that puzzled me as well. Great! Dave.
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Old 28th Nov 2007, 12:08 pm   #11
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Default Re: PCR Type differences

Thanks for all of that, very enlightening. Especially the use of them post D Day. I'm still left with the question of why I've got what looks like a PCR (not 1,2 or 3) with internal speaker and separate PSU but with a 6V6 in the o/p stage. I am toying with the idea of putting it back to a normal PCR with the EL32 in this position but I was wondering whether anyone had seen one of these before.

Robin
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Old 28th Nov 2007, 1:33 pm   #12
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Default Re: PCR Type differences

Quote:
PCR:
Tuning range: 850 - 2,000 metres; 200 - 550 metres; 6 - 18 MHz.
Contains an internal speaker.

PCR1:
Tuning range: 860 - 2,080 metres; 190 - 570 metres; 5.6 - 18 MHz.
Contains an internal speaker.
I am not sure about this - it looks like a documentation artefact to me.

I have a set calling itself just PCR. But its tuning range is as per PCR1 above, and to me it looks like the other range is just a simplifed view of the same thing.

I suggest that PCR and PCR1 are exactly the same thing and means that they continued making the original PCR set after the 2&3 came out, so it might well then be called PCR1.
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Old 29th Nov 2007, 12:16 am   #13
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Default Re: PCR Type differences

If you want to establish exactly what PCR type yoiu have got PCR or PCR1 then check out some of the component values, the PCR and PCR1 have differing component values in various parts of the circuit . This should confirm what type it is. Try this reference
http://vintageradio.me.uk/military/prc2/PCR_EMER.pdf

this is a copy of the original reme documentation

Mike
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Old 29th Nov 2007, 8:00 pm   #14
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Default Re: PCR Type differences

Hi all,
The fun continues.

Looking a bit closer, this is definitely a PCR, not a 1, which to be fair is what it says on the manufacturer's plate. It appears to have had a couple of add ons, the object of which I can only guess at.

1) A screened cable goes from the grid of the last IF EF39 to a switch mounted on the front panel which is also connected to the gain control by an obvious add on and then goes to a screened cable that is tied to the grid cable for the EBC33 detector and AVC valve.
2) A very odd wirewound resistor is connected across the heater of the EBC33.
3) The coupling capacitor from the EBC33 to the EL32 is connected to pin 5 which is the grid for a 6V6.
4) The top cap screened cable for the EL32 is connected to the grid of the 6V6 and the other end is floating free.

I guess some attempt has been made to play with the gain of the IF stage and also repace the EL32 with a 6V6.

I'm going to put it back as was but I'll need a new top cap for the EL32. This is one of the sort that is quite large so that a resistor can be hidden within it. I'll post a request on the parts wanted.

Cheers

Robin

Oh, by the way. According to my paperwork, the PCR, PCR 1 and PCR 2 all had the same coverage 800 - 2100 M, 190 - 570 M, 6 - 18 MHz.
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Old 29th Nov 2007, 8:18 pm   #15
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Default Re: PCR Type differences

In you first post Robin you thought the mods looked a bit professional so the Michael R suggestion in post 9* could be the best route. I always thought the PCR's [whatever type] were a bit superior to the supposed useage. Perhaps the VMARS site might help? Somebody must have worked on them. Dave
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Old 29th Nov 2007, 8:21 pm   #16
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Default Re: PCR Type differences

Ah, I think I'll withdraw my earlier opinion now I've dug a bit more. I was foxed by the fact that who ever did these could put black self amalgamating tape on very neatly, often a pointer to a pro job.

Now I've dug deeper, very definitely not

Robin
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Old 29th Nov 2007, 8:46 pm   #17
dave walsh
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Default Re: PCR Type differences

Ok you may be losing interest [or the will to live] Robin but having just looked at that Pye link put up by Michael, the mystery deepens about the PCR Gen Purpose Comms or "Invasion" Receiver and especially the mythical Receiver Type PTR! Fascinating that no-one seems to know. Dave
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Old 30th Nov 2007, 12:52 am   #18
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Default Re: PCR Type differences

Just had a look. Yes, very interesting.

Not lost will to live

Robin
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Old 27th Oct 2013, 9:34 pm   #19
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Default PCR Differences, re-opening thread closed 2007

Reading this thread made me think that this is the place to put my question. So here it is.
The set I have is a PCR3 ( MW;SW1,SW2 no internal speaker ). What it does have is an internal mains power supply ( all other PCR's do not have this ) and because of this I started looking around. Found some private mods but no substantial evidence of a factory mod. What I noticed on mine ( see radiomuseum.org PCR 3 where I posted pictures ) is the following:
1. There is a valve base cutout next to the output transformer on all PCR's
2. There are some unused mounting holes near the front panel beside the choke
3. What are they for?
So my guestimation is that it was maybe planned to have a mains-only version. Looking at the chassis underside the power supply components do not seem to have been added later on, the nasty paper/wax capacitor on the DC output of the 5Y3 rectifier is the same type as all other capacitors. That speaks for a factory job!
Does anyone have an idea or has come across a similar PCR?

Last edited by Station X; 27th Oct 2013 at 10:18 pm. Reason: Threads merged.
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Old 19th Dec 2013, 11:33 pm   #20
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Default Re: PCR Type differences

Hello Siekari,

I've recently picked up a tatty but serviceable PCR2 (lw, mw and sw, without speaker). This has an internal mains power supply installed, and appears to have been done very professionally.

The spare valve holder slot referred to, is occupied by a rectifier valve, 6x5g, and a mains transformer is installed in the space between this and the choke. The mains transformer is of the type fitted to "wartime utility sets", and is tar coated.

I believe the sets were designed, as you say, for future mains power conversion. This conversion looks well executed, and I believe was done by REME (royal electrical mechanical engineer) service depot. The electrolytic cap on the rectifier is an RS 50s type which suggests conversion around the mid 1950s. The original electrolytic are dated May 1944.

I hope this is helpful.

Best regards,
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