PCB's - What have I got?

[McMurdo]

I've just been given as a gift a box of parts which I have a hunch are all mobile radio related but not really sure. (suspect from an estate dispersal).

Below are 2 pcbs (partially dismantled) one of which says 276250 RF MIXER ASSY.

There are also a quantity of NOS CV2798, Sylvania 6BH6 and CV2797 valves.
There's also boxes of 6V LES bulbs.
A box of ignition suppressor capacitors.

What were they out of?

[G6Tanuki]

The PCBs look like the RF/first-mixer boards from something like a Pye Vanguard or Cambridge from the early sixties.

CV2797 is the QQV06/40 - as used in the Vanguard as PA.

CV2798 is QQV03/10, used as driver in the Vanguard and PA in the Cambridge.

[Bazz4CQJ]

I'm pretty sure those are Pye, Vanguard or Cambridge...but the transistors look wrong. At that time, Pye used a lot of the NKT series, something about the size of an OC171, but gold in colour. Those are smaller, like say BC108. Wonder if they look like some tried to upgrade them by changing transistors? Could they be something later like a Westminster?

B

[G6Tanuki]

The front end transistors in the Cambridge and Vanguard were little ones made by Texas Instruments, Germanium, with numbers like GM0290.

They were in a TO18 style can.

There was - at least in the VHF ones, also a Germanium mixer diode - something like a GEX66.

The IF strip used Mullard type OC170s at 10.7MHz and GEC GET series for the 455KHz bit, with Newmarket for audio and inverter.

Definitely not a Westminster!

[McMurdo]

Interesting! I've just googled Pye Vanguard and there's one with the lid off and those boards inside. They also look like the same metal to18 transistors. These are AF139 and have 4 legs, all fitted on the board. (there's one glass diode in there too and an odd BC252 that has obviously been fitted by a third party)

[G6Tanuki]

AF139/239 were pretty much the equivalent of the TI transistors.

[Bazz4CQJ]

The Vanguard I owned (AM25B) ? had valves in the front end of the Rx, maybe an E88CC, then came all the NKT's. Perhaps there were later models, or perhaps the FM set, where they went solid state?

B

[McMurdo]

Here's a lovely section about the vanguard on the pye museum web site, some great period photo's on there.

http://www.pyemuseum.org/divisions/communications/pye_telecom/gallery/vanguard.php

[G6Tanuki]

Originally Posted by Bazz4CQJ

The Vanguard I owned (AM25B) ? had valves in the front end of the Rx, maybe an E88CC, then came all the NKT's. Perhaps there were later models, or perhaps the FM set, where they went solid state?

B

The first generation of Vanguards (and, IIRC Cambridges too) did have a valve front end. They were battery murderers, specially since back then almost every car had a generator rather than the more effective alternators we have now.

The transistor-receiver Vanguard only took around 100mA on receive, compared to an amp or more for the valve-receiver version.

On transmit, a FM25 Vanguard properly aligned would put out at least 50 Watts of carrier on 144MHz, at a cost of something like 12 to 15A of 12V !

[Bazz4CQJ]

Weren't there a couple of companies (Garex ?) who were making "2m convertors" out of those front-end boards? Stick them in a diecast box and output 9.7-11.7MHz to a general coverage Rx.

B

[G6Tanuki]

Garex had some sort of deal to take ex-Pye-Telecom scrap and rework it for the amateur market.

They did the Twomobile and Fourmobile which made use of Cambridge/Vanguard bits but with a VFO rather than crystal control for the receiver.

Http://steve-morton.com has some background, along with photos of the inside of a Garex 2M receiver which shows the L-shaped RF/mixer board as shown in the first post of this thread.

[Bazz4CQJ]

Yes, I think Garex were the big name, but especially in the North of England, M&B radio in Leeds also acquired scrap by the ton from Pye. Pretty much overnight, 2m went from a wasteland to being very busy.

B

[CambridgeWorks]

So long ago now, but maybe the one with less cans is a uhf one??
There was something about the conversion from UHF down to first IF 10.7.
They used an if in the 70MHz region, I THINK?
As I say, well over 40 years now...
Rob

[CambridgeWorks]

Originally Posted by Bazz4CQJ

Yes, I think Garex were the big name, but especially in the North of England, M&B radio in Leeds also acquired scrap by the ton from Pye. Pretty much overnight, 2m went from a wasteland to being very busy.

B

Baz, AJH Electronics, Tony Hibberd and Brian Bamber electronics were also fairly big retail advertising dealers/suppliers at various times in 70s and 80s.
Rob