R 103

[Malcolm G6ANZ]

I have been given a basket case R103 receiver from circa 1943. It's been living in a barn for the last x years. As a long term project I hope to get it working again
There is no information on the net regarding this model only the Canadian version. Does any one have information on this type?

Malcolm

[G4XWDJim]

This is the British model. I’m sure vmars will have the info in their manuals website FOC.

Jim

[Malcolm G6ANZ]

Thanks Jim,
I have checked the VMARS site and the only R 103s they have are the Canadian versions.

[G4XWDJim]

Hi Malcom,

I’ve just looked in my Wireless for the Warrior and there’s 8 very clear pages on it in volume 3. I’d forgotten it was there.

I don’t have a scanner now but could probably photograph the pages and email them to you.

Let’s see if you get a better offer from someone with a better set-up than me but I’ll do it if you don’t.

The trouble with the book is that it’s very thick and not easy to hold the pages flat when taking the photo.

Jim

[Malcolm G6ANZ]

Excellent. Thanks

[trh01uk]

Malcolm,

I've turned up a rather messy copy of the technical manual, which I will post here.Its in two parts, and I will have to post separately to keep within file size limits. Here's part 1.

And by the way, the set is a R103A, not R103.....

Richard

[trh01uk]

Here's most of Part II - which contains more technical stuff. Its missing the schematics which I will have to post separately.

Richard

[trh01uk]

It turns out this manual file has two schematics attached, which as far as I can tell are the same, but one may be a little clearer than the other at certain points, so I will post both. Here's the first one.

Richard

[trh01uk]

And the second schematic.....

[Malcolm G6ANZ]

Richard , many thanks. The PDFs are perfectly readable. As I said the set was left in a barn for a good number of years and is somewhat rusty underneath and some of the coils and components are damaged, so its a long term project to get it up and running.
First thing is to give it a good clean and find my way around it and see what's missing or damaged.

[Malcolm G6ANZ]

I've looked at the receiver and compared it with the diagrams. The RF/IF sections appear at first glance to be correct. The problems lie in the PSU area. The diagrams for both the Canadian and UK versions show the set as having a vibrator and gas filled rectifier for the HT and the UK version having a transformer and a vibrator. The heater supply coming from the mains transformer or the 6v battery supply. The diagram shows two switches used to go between mains supply and vibrator supply. mine does not have these switches, nor any redundant holes where they might have been.
My set has no vibrator and only space for an octal rectifier, of some type as mine is missing. There is only a three way socket on the side for power input, so this 'might' be for mains, possibly, or HT and LT from an external vibrator supply. There is a transformer fitted so the supply is most likely to be AC, be it mains or vibrator.

[trh01uk]

Malcolm,

I see my previous comment about R103 and R103A has probably only confused things - it certainly had me confused! And the manual I have sent you relates to the R103A, which you do not have! Yours is definitely a R103 - and there is also a Canadian R103, which again is quite different to yours and the R103A. Sorry for muddying the waters here!

So you should discard the manual and schematics I have sent you, since they relate to the R103A, which was a later development of the R103.

The R103 (which you have) has a separate power unit which contains a vibrator. So the receiver (according to Wireless for the Warrior vol.3) runs on an HT of 200V (at 72mA), and and LT supply, which appears to be 6.3V from my reading of the correct schematic.

The LT supply is derived as follows. The power unit takes in 12V DC. There is a 2.2 ohm dropper resistor (R10A), in the power unit, which is in series with the LT supply to the receiver. A table in WftW indicates that the filament voltages of the valves (which are all in parallel) is 5.7 volts. LT current is stated as 2.5 amps, which should drop 5.5 volts, thus reducing a 12V supply to 6.5 volts. OK - so the number don't quite stack up!

What this means is that if you ever get as far as powering up the receiver, you can run the valve filaments on a 6V DC supply. If you have a high voltage bench supply you could feed 200V to pin 1 of PP1A (the power supply connector on the set).

Unfortunately, Jim's comments about WftW being hard to copy is only too true. The schematic in the book is particularly poor quality. I will have a go at photographing it, but we will have to see whether the result is usable.


Richard

[Malcolm G6ANZ]

Thanks. That makes sense. The transformer I can se must be the audio output and the missing valve the audio output.
I’m a long long way from powering it up as it needs a total strip down and deriding as well as a couple of coils needing repair. I’ll keep looking for a 103 diagram 😄
I investigated buying a copy of WforW but the prices have put me off.

[trh01uk]

Malcolm,

I'm not surprised you are put off buying WftW. It isn't worth it for one set. I have been in touch with the author in the long past, and enquired about copying. He takes the same view as a public library would: copy only what you need, and keep it for personal use only. And as he pointed out, the source documents for his books are all in the public domain anyway.

I've managed to make some copies of the schematic and the parts list (so far). See attached files. Not wonderful copies but that's difficult to achieve with two hands, a camera, and a book that won't lie flat!


Richard

[trh01uk]

Malcolm,

and here is a copy of the layout diagrams of the receiver. There are layouts for the power unit, but I guess that's a bit academic at the moment.


Richard

[trh01uk]

Malcolm,

having just viewed the photos of your R103 at the start of this thread, I am reminded that I have a similar "basket case" awaiting restoration at some future date. A Wireless Set No.42, which apparently was rescued from a rubbish heap after 35 years!

I would be interested to hear how you intend to tackle the restoration? Will you do a complete strip down to the last nut and bolt, and clean every part, including rust, grease and general grime? If its to be operational, I presume you will end up replacing most resistors and capacitors with modern equivalents? Do you keep the original wiring or replace it with new?

Richard

[Malcolm G6ANZ]

Richard that’s excellent. The diagrams and layouts look to be the same as my set. Many thanks.

[Malcolm G6ANZ]

I intend to get it working. It is in a bad way with lots of rust on the steel work and several damaged coils and trimmer caps. So I think I’ll have to slowly dissemble it and do a rebuild. Most of the wiring insulation is perished so that will need replacement as well as most of the caps and resistors. 😄

[trh01uk]

Malcolm,

well, please consider posting regular updates to this thread, so that we can see how you tackle this "basket case". If dealing with rusty chassis has been covered elsewhere it has passed me by. The only technique I am aware of on that front, is sand blasting, followed by zinc plating, both of which tend to be commercial processes - and expensive.


Richard

[Malcolm G6ANZ]

I will do that but it will at very infrequent intervals