C&W Type S2 RF generator - UK Vintage Radio Repair and Restoration Discussion Forum

ITAM805 · 3rd Feb 2014, 6:46 pm

hi folks

Has anyone information on the this RF signal generator? The mains transformer was adrift inside but otherwise it seems all there. It sports two valves, a 7193 and another similar looking type with no markings. The dial suggests it's range is from 100kHz to 75mHz. I cant find any info on the type?

Many thanks

Herald1360 · 4th Feb 2014, 1:31 pm

That has a distinct look of "Small outfit using surplus components" about it.

The valves say "19 set Dalek" and the trimmers "R1155" to me......

Both valves are probably the same ie:

http://www.mullardmagic.co.uk/mullar...-wireless.aspx

ITAM805 · 4th Feb 2014, 3:27 pm

You're right Chris. It looks post WW2, maybe early 50's

The mains transformer is burnt out and one of the Daleks has an open filament. But I'd liked to know more about it and get it going again if possible.

WME_bill · 4th Feb 2014, 4:40 pm

S2 signal generator. Yes, I agree with Herald1360. Very much a 1950's using war surplus. The valves are CV6/E1148/Det20/2C22/7193. A small triode, used I seem to remember as the vhf transmitter for the WS19 set. Hence the unique arrangement of anode and grid to the two top caps. The rectifier looks a usual STC selenium type. I can't read the type number, but I'd expect 150v, 50ma as a guess.
It should be too difficult to trace out the circuit. The transformer probably 6.3V and 120 to 200V at 25 ma, and very uncritical.
If you a stuck for a CV6, I can have a rummage. wme_bill

ITAM805 · 4th Feb 2014, 6:44 pm

Thanks Bill.

Re the valves, on closer inspection they are different in anode length at least, unless they're within the CV6 range? The second is marked "V.R.135"

WME_bill · 4th Feb 2014, 9:32 pm

CV6=VR135=7193=Det20. All the same. I suspect it was designed specially to Pye requirements as the VHF transmitter valve for the No19 set. The original was probably the MOV E1148, an experimental number. Later made by GEC/MOV in Hammersmith, Marconi and by RCA in US. wme_bill

ITAM805 · 4th Feb 2014, 10:10 pm

OK, thanks Bill

ITAM805 · 20th Feb 2014, 9:49 pm

I'm happy to report that this old generator lives again! However there are a few anomalies which I cant figure out and could do with some advice please. I believe it's a type of Hartley oscillator - but forgive me if the circuit sketch isn't quite correctly laid out, you'll get the idea hopefully!

There are six ranges (not seven as indicated by the dial

), the lower three (100kHz-1.9MHz) are working perfectly.

However, on the 12MHz-40MHz range when tuning up, oscillation doesn't occur until around 20MHz - thereafter it works normally up to 40MHz

Likewise, the 4.5MHz-13MHz range doesn't start oscillating until around 5.5MHz

On the 1.5MHz-5MHz range, tuning up it gets to 5MHz before full rotation but then suddenly drops down to 3MHz when the tuning cap is fully rotated (open) - turning it back it goes back to up to 5MHz?

I have tried 3 different valves in the RF position but with the same outcome. The only waxey in the RF section was the anode (decoupler?) which I replaced but with no change. The grid cap is a mica type with no markings but measure 150pF, the 22R resistor measures 23R, the 56K measures 64k. The anomalies are present whether the AF modulator valve (not shown) is in or out of circuit.

Any ideas folks?

Many thanks

Herald1360 · 21st Feb 2014, 12:52 am

The "7th" range is simply the second harmonic of range 6. The RF output is probably distorted enough for a fair amount of this to exist on all ranges.

Suggestions? Dirty switch contacts? Try replacing that "mica" capacitor anyway?

ITAM805 · 22nd Feb 2014, 5:13 pm

Thanks Chris

I didn't think about the harmonics on the upper range, not that I have anything that'll receive above 30MHz anyway! I tried replacing the silver mica cap but no change so then I tried subbing the 22R with a 47R that was to hand - success!

I still get the weirdness on the 5MHz range but everything else is working so I'll experiment with some other value resistors and see what's what.

I have to admit that my test gear leaves a lot to be desired, the scope (TQ D1011) only goes up to 10MHz and has recently lost it's sync ability and the frequency meter is a cheapo Chinese one that is a little flakey but it's better than nothing

3rd Feb 2014, 6:46 pm	#1
ITAM805 Nonode Join Date: Jul 2010 Location: Folkestone, Kent, UK. Posts: 2,172	C&W Type S2 RF generator hi folks Has anyone information on the this RF signal generator? The mains transformer was adrift inside but otherwise it seems all there. It sports two valves, a 7193 and another similar looking type with no markings. The dial suggests it's range is from 100kHz to 75mHz. I cant find any info on the type? Many thanks Attached Thumbnails

4th Feb 2014, 1:31 pm	#2
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: C&W Type S2 RF generator That has a distinct look of "Small outfit using surplus components" about it. The valves say "19 set Dalek" and the trimmers "R1155" to me...... Both valves are probably the same ie: http://www.mullardmagic.co.uk/mullar...-wireless.aspx __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

4th Feb 2014, 3:27 pm	#3
ITAM805 Nonode Join Date: Jul 2010 Location: Folkestone, Kent, UK. Posts: 2,172	Re: C&W Type S2 RF generator You're right Chris. It looks post WW2, maybe early 50's The mains transformer is burnt out and one of the Daleks has an open filament. But I'd liked to know more about it and get it going again if possible.

4th Feb 2014, 4:40 pm	#4
WME_bill Octode Join Date: Oct 2007 Location: Exeter, Devon, UK. Posts: 1,554	Re: C&W Type S2 RF generator S2 signal generator. Yes, I agree with Herald1360. Very much a 1950's using war surplus. The valves are CV6/E1148/Det20/2C22/7193. A small triode, used I seem to remember as the vhf transmitter for the WS19 set. Hence the unique arrangement of anode and grid to the two top caps. The rectifier looks a usual STC selenium type. I can't read the type number, but I'd expect 150v, 50ma as a guess. It should be too difficult to trace out the circuit. The transformer probably 6.3V and 120 to 200V at 25 ma, and very uncritical. If you a stuck for a CV6, I can have a rummage. wme_bill

4th Feb 2014, 6:44 pm	#5
ITAM805 Nonode Join Date: Jul 2010 Location: Folkestone, Kent, UK. Posts: 2,172	Re: C&W Type S2 RF generator Thanks Bill. Re the valves, on closer inspection they are different in anode length at least, unless they're within the CV6 range? The second is marked "V.R.135" Attached Thumbnails

4th Feb 2014, 9:32 pm	#6
WME_bill Octode Join Date: Oct 2007 Location: Exeter, Devon, UK. Posts: 1,554	Re: C&W Type S2 RF generator CV6=VR135=7193=Det20. All the same. I suspect it was designed specially to Pye requirements as the VHF transmitter valve for the No19 set. The original was probably the MOV E1148, an experimental number. Later made by GEC/MOV in Hammersmith, Marconi and by RCA in US. wme_bill

4th Feb 2014, 10:10 pm	#7
ITAM805 Nonode Join Date: Jul 2010 Location: Folkestone, Kent, UK. Posts: 2,172	Re: C&W Type S2 RF generator OK, thanks Bill

20th Feb 2014, 9:49 pm	#8
ITAM805 Nonode Join Date: Jul 2010 Location: Folkestone, Kent, UK. Posts: 2,172	Re: C&W Type S2 RF generator I'm happy to report that this old generator lives again! However there are a few anomalies which I cant figure out and could do with some advice please. I believe it's a type of Hartley oscillator - but forgive me if the circuit sketch isn't quite correctly laid out, you'll get the idea hopefully! There are six ranges (not seven as indicated by the dial ), the lower three (100kHz-1.9MHz) are working perfectly. However, on the 12MHz-40MHz range when tuning up, oscillation doesn't occur until around 20MHz - thereafter it works normally up to 40MHz Likewise, the 4.5MHz-13MHz range doesn't start oscillating until around 5.5MHz On the 1.5MHz-5MHz range, tuning up it gets to 5MHz before full rotation but then suddenly drops down to 3MHz when the tuning cap is fully rotated (open) - turning it back it goes back to up to 5MHz? I have tried 3 different valves in the RF position but with the same outcome. The only waxey in the RF section was the anode (decoupler?) which I replaced but with no change. The grid cap is a mica type with no markings but measure 150pF, the 22R resistor measures 23R, the 56K measures 64k. The anomalies are present whether the AF modulator valve (not shown) is in or out of circuit. Any ideas folks? Many thanks Attached Thumbnails Last edited by ITAM805; 20th Feb 2014 at 9:58 pm.

21st Feb 2014, 12:52 am	#9
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: C&W Type S2 RF generator The "7th" range is simply the second harmonic of range 6. The RF output is probably distorted enough for a fair amount of this to exist on all ranges. Suggestions? Dirty switch contacts? Try replacing that "mica" capacitor anyway? __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

22nd Feb 2014, 5:13 pm	#10
ITAM805 Nonode Join Date: Jul 2010 Location: Folkestone, Kent, UK. Posts: 2,172	Re: C&W Type S2 RF generator Thanks Chris I didn't think about the harmonics on the upper range, not that I have anything that'll receive above 30MHz anyway! I tried replacing the silver mica cap but no change so then I tried subbing the 22R with a 47R that was to hand - success! I still get the weirdness on the 5MHz range but everything else is working so I'll experiment with some other value resistors and see what's what. I have to admit that my test gear leaves a lot to be desired, the scope (TQ D1011) only goes up to 10MHz and has recently lost it's sync ability and the frequency meter is a cheapo Chinese one that is a little flakey but it's better than nothing Attached Thumbnails