STV280/40 Stabilovolt Valve

[pwdrive]

A link to this device for those that may be interested, the link also contains circuit info for a power supply.

http://www.r-type.org/exhib/aab0008.htm

Lawrence.

[AlanBeckett]

A fascinating gadget. I've never seen it used in anything.
What was it used in? They must have made it in reasonable quantities.
They do exist - http://www.ebay.co.uk/itm/Marconi-VS68-S...lephony_SM&hash=item1e7dc86a1a

Alan

[pwdrive]

A fascinating gadget. I've never seen it used in anything.
What was it used in? They must have made it in reasonable quantities.
They do exist - http://www.ebay.co.uk/itm/Marconi-VS68-S...lephony_SM&hash=item1e7dc86a1a

Alan

Neither have I Alan until I took the lid off that Marconi CR150, so for me it's the first time I have seen one in the flesh, not exactly sure how it's configured in the CR150, I would have to consult the circuit diagram....I shall have a look.....

Lawrence.

[pwdrive]

Ok Alan, anodes 2, 3 and 4 are strapped together to give 140 volts stabilized, anode 1 (the 70v anode) is strapped to cathode via a 470k, cathode connected to chassis.
The stabilized 140 v is supplied as the IF/RF/Osc HT.

Edit: It's unusually heavy for it's size.

Lawrence.

[AlanBeckett]

When was the CR150 designed? Did it predate the VR150 or did it need more current than the VR150 could manage?

Alan

[pwdrive]

When was the CR150 designed? Did it predate the VR150 or did it need more current than the VR150 could manage?

Alan

I can't find the initial production start year for the CR150 Alan, at a guess sometime during WW2.
I'm not sure when the VR150 was first produced but the VR150 was used in the RCA AR88 which I believe was primarily a wartime receiver and that receiver was initially thought out circa 1939 ish and pushed into service as early as 1941 from all accounts.

Looking at the specs I guess Marconi could have used the VR150 maybe, but Marconi always had quirky ideas ie: they produced the BL63 valve as used in the R1155, a one off if ever there was one.

The STV280/40 in the receiver I have has the Marconi logo on it.

I have always found Marconi stuff difficult to research despite it being quite a large company in it's day.

I will have a surf for the VR150 history, if I find owt I shall report back.

Lawrence.

[pwdrive]

Various sources seem to indicate 1939 for the VR150, OD3.

lawrence.

[Skywave]

Marconi always had quirky ideas . . .
I have always found Marconi stuff difficult to research, despite it being quite a large company in its day.
Lawrence.

That's my experience, too. And it's also been my experience that their 'quirky ways' seemed to extend into the physical manifestations of their kit, too. Having said that though, and in all fairness, when Marconi kit is working the way it was intended, it does work very well. Just a pity that it is often such a headache to do maintenance on.

Al. / Aug. 9, 2013 //

[pwdrive]

Yes they can be awkward to work on, in some cases it's easier to remove the sub assembly that the offending component(s) are on and work on it in comfort on the bench.
Fortunately the wiring on that CR150 I've just acquired is in good condition but some of the tubular can capacitors look suspect as does a stressed resistor near the voltage stabilizer but that's for another day.

Lawrence.

[AlanBeckett]

... when Marconi kit is working the way it was intended, it does work very well. Just a pity that it is often such a headache to do maintenance on.

You should have told me that before I got stuck into the 'scope

Alan