Arfa Daily wrote in message
...

"N_Cook" wrote in message
...
http://home.graffiti.net/diverse:gra...miniscope9.jpg

Made for ultra portability fits in an 8x11x 2.5 inch case when the
thyratron
and vibrator are removed from the chassis and stowed near the hinge.
What
war time use was there for such a small 'scope, with in-the-field 12V
supply
capability?
War finish presumably means the off white enamel rather than black
crackle
finish.
Plate on the brown casing lid
Miniscope
Miniature C/R oscilloscope
Pattern No 58259

Stencilled labels on the case are
R.L. 4
and No 1

Presumably somewhere would have info on the pattern number.
Even using "-dr who" googling does not find anything on Miniscope or
that
pattern number, plenty on the 6K25 thyratron but nothing on 9 pin VR91,
10E/92 voltage regulator? or 9 pin CRT
VCR 522, 10E/787, Design Inspected CRT 4
(shattered probably when the shoulder carrying strap broke and corner
brace
broke off and split occured in the "suitcase" )
no other valves,
also Masteradio G650 12V vibrator, military trident symbol in a couple
of
places , after an A on the VR91 and before a Z on the CRT
side panels missing, someone has crudely bodged in pot .


http://home.graffiti.net/diverse:gra...miniscope1.jpg
http://home.graffiti.net/diverse:gra...miniscope2.jpg
http://home.graffiti.net/diverse:gra...miniscope3.jpg
http://home.graffiti.net/diverse:gra...miniscope4.jpg
specs etc on hinge-down, prop-up plate
http://home.graffiti.net/diverse:gra...miniscope5.jpg
http://home.graffiti.net/diverse:gra...miniscope7.jpg




VR91 / EF50 was used in many wartime radios and early radar units (PPI and
pulse position). I owned a '1392 ex RAF vhf control tower receiver for
many
years, and that was full of them.

Arfa



I downloaded the GEC schematic from
http://www.thevalvepage.com/download...pe.pdf&dir=gec
but substantially different, except 4V and 6.3V heaters agree with
VCR 522
and VR91.
Looks as though I'll have to get/derive the
CRT VCR 722/ CV1522 or related E4103/B/4 / CV320 / CV967 / CV335 pinout and
maybe de-topologize for the schematic.
But I'd really like to find out what sort of use it was put to, most likely
tech
museum or forum to try ?
Very large print , 1 inch high letters "R.L.4" = radio location unit 4 ?

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/