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Wartime Minicsope oscilloscope , any info/sources ?

N

nesesu

Jan 1, 1970
0
I have to disagree. No laboratory equipment would be made deliberately too
small, requiring the removal of parts before placing in a protective
housing.
This was made to be ultra-portable, the smallest possible carrying case for
discretion, airbourne use, or covert reason, I would suggest. Routine
military equiptment is not made for the effete to carry around. Come to
think of it wartime airbourne radios etc were not made deliberately lightor
compact.

Drawing out the preliminary circuit topology is half complete, i will place
on the pagehttp://home.graffiti.net/diverse:graffiti.net/miniscope.htm
when nearer complete, before unravelling for the intermediary schematic.
I agree with you Nigel. The fact it runs on 12VDC [the GEC Miniscope
does not] would indicate it was for mobile or field use where where
'mains' power was unavailable. I was thinking the RL might be 'radio
location' where it could be used for timing compaison or phasing check
as ground mobile. The transit case and the external vibrator smack of
a 'modified' unit for temporary applications. I get the impression
that the GEC uses a horizontal multivibator so the thyratron may also
be a mod for some special requirement. Since it looks to be able to
operate from mains and aircraft power as well, the application was
likely broadly used. Also could be for adjusting or troubleshooting
high speed data circuits [teletype].

Neil S.
 
N

N_Cook

Jan 1, 1970
0
I have to disagree. No laboratory equipment would be made deliberately too
small, requiring the removal of parts before placing in a protective
housing.
This was made to be ultra-portable, the smallest possible carrying case for
discretion, airbourne use, or covert reason, I would suggest. Routine
military equiptment is not made for the effete to carry around. Come to
think of it wartime airbourne radios etc were not made deliberately light or
compact.

Drawing out the preliminary circuit topology is half complete, i will place
on the pagehttp://home.graffiti.net/diverse:graffiti.net/miniscope.htm
when nearer complete, before unravelling for the intermediary schematic.
I agree with you Nigel. The fact it runs on 12VDC [the GEC Miniscope
does not] would indicate it was for mobile or field use where where
'mains' power was unavailable. I was thinking the RL might be 'radio
location' where it could be used for timing compaison or phasing check
as ground mobile. The transit case and the external vibrator smack of
a 'modified' unit for temporary applications. I get the impression
that the GEC uses a horizontal multivibator so the thyratron may also
be a mod for some special requirement. Since it looks to be able to
operate from mains and aircraft power as well, the application was
likely broadly used. Also could be for adjusting or troubleshooting
high speed data circuits [teletype].

Neil S.


******

There was no original probes just some home-brew croc-lead things from the
60s or 70s , of much the same date as the bodged pot.
I will test the 6K25 and the VR91 as EF50 settings, heaters are ok
 
N

N_Cook

Jan 1, 1970
0
An email response from the guy at the valvepage site

Yes that GEC is internally quite different to mine, and the use of bigger
valves suggests an earlier design.

The catch on that case looks very un-military-like as it and the case look
so fragile.

Maybe the crt broke when the chap in the aircraft got fed up and threw the
darn thing out of the aircraft - the shaped controls on mine are still
fiddly, yet the controls on the front of yours would I think be impossible
to use with gloves on !

Also, where on earth do the valves go ? There doesn't seem to be any space,
and I also can't spot any ht rectifier.

I've seen quite a few of the GEC scopes like mine but not encountered any
like yours before so I can't really add any information. Perhaps you could
let me know if you find out more. Also, could I scrounge a couple of pics
for my website ? Just a small pic of the front and one of the side, just
enough so if a visitor sees my page they'll think "that looks just like
mine" and they can then follow a link to your page.
 
N

N_Cook

Jan 1, 1970
0
I found 2 unlabelled black painted glass Si diodes of the 70s , not original
for the added reason that 2 solder points were to wires and not tag board
tags. Se rectifiers been around since earlier than 1933 but where was there
space for any. Even if the vibrator was originally synchronous type , would
it be possible to use such a vibrator to rectifierless feed mains in , via
the transformer to such a vibrator, to allow 12V and 180/230V ac use?
The mains cable seems to go to the output side of the vibrator, with no
mechanical interlock to lockout other than someone remembering to unplug the
vibrastor, or does it matter ?.
For the 4 pin vibrator, that came with it, gum on Masteradio label is bad
and original un-re-badged label under is
Mallory G650
Indianapolis Ind
Made in USA

Anyone have specs for the G650 ? or even whether synchronous types could be
in only 4 pin format
 
G

Geo

Jan 1, 1970
0
Mallory G650

The only reference I found was a google cached page which include this info on a
PSU:-

"The Power Supply Unit is running from a 6 V car battery using a Vibrator or
from the mains at 110, 150 or 220 Vca 50 Hz.
The Vibrator is of the "nonsycronous" 4 pins type (B MKII or Mallory 650)
The mains voltage value can be changed by a switching system on the front.
A valve 6X5G is used like rectifier.
When the set is to be used on the mains, the vibrator must be removed to prevent
burning up. "
 
N

N_Cook

Jan 1, 1970
0
Geo said:
The only reference I found was a google cached page which include this info on a
PSU:-

"The Power Supply Unit is running from a 6 V car battery using a Vibrator or
from the mains at 110, 150 or 220 Vca 50 Hz.
The Vibrator is of the "nonsycronous" 4 pins type (B MKII or Mallory 650)
The mains voltage value can be changed by a switching system on the front.
A valve 6X5G is used like rectifier.
When the set is to be used on the mains, the vibrator must be removed to prevent
burning up. "

What i suspected. I happened to have rebuilt the contacts of a synchronous
one last year and that was 7 pins. At the moment I'm bogged down with
confusing cap colour codes.
 
N

nesesu

Jan 1, 1970
0
What i suspected. I happened to have rebuilt the contacts of a synchronous
one last year and that was 7 pins. At the moment I'm bogged down with
confusing cap colour codes.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://home.graffiti.net/diverse:graffiti.net/- Hide quoted text -

- Show quoted text -

FWIW, Nigel, we used to use caps not unlike the ones in your 'scope
and until the early '60s they were identified by 'bin numbers' which
were simply assigned as new values were needed. Since there were less
than 1000 values in use, a 3 colour code sufficed. Unless you had the
'rosetta stone' to co-relate the bin number to value, the colour
coding meant nothing. I am sure a similar scheme was used by many
manufacturers in the '30s-'50s. I know CGE/RCA/Westighouse in Canada
used a 3 digit numeric code on some of their paper caps during that
period.

Neil S.
 
N

N_Cook

Jan 1, 1970
0
This is the preliminary node map for the scope
http://home.graffiti.net/diverse:graffiti.net/miniscope_node_map2.jpg
Scanner does not like full A4 useage.
Letters E, K and C along the top

2 tag boards running vertical, numbered from bottom S (16) and R (16) then P
(11) and Q (11),
colours match major component pinning numbers to node numbers.
ground lines not added and some components around the front panel pots,
switches and 2 3.5 mm i/p sockets (feintly marked as worn off , maybe read
INVERT and GAIN not readable on the earlier pics) not transcribed. Some
unplaced loose wires
and 2 caps covered in laquered cloth so left in place as unknown values and
puffy cap values are assumed , ignoring the green and yellow "multiplier"
dots that are probably temp or tolerance values.
polarised caps marked with a - .
QQ is unkown function as knob missing and other Q pot functions as letters
on the knobs, as found.
There are bound to be still more errors, I've just noticed the 22K resistor
apparently going to doubley N/C K6, maybe used as a tag.
M & VIB wiring and power select shorting plug arrangement is probably much
like the valvepage schematic including the vib, for the later miniscope.
Power cable wiring Y,R,B is the same in both cases
Next intermediary schematic is placing the valves etc into the optimum
coloured nodes and un-knotting to a certain extent.
Nothing powered up so far, a few volts from variac may resolve a few
problems, and valves not tested yet.
Primary of M is probably ok , selecting 230V is 129 ohm and 180V is 75 ohm

The socket for the vib is badly fixed , one bolt is skew as it interferes
with something else on the chassis. So maybe not original vib type but I
don't see how a synchronous type could have made it Si diode rectifierless.
What were the smallest Se rectifiers available in the 1940s for this sort of
application ?

page devoted to this project
http://home.graffiti.net/diverse:graffiti.net/miniscope.htm
 
N

N_Cook

Jan 1, 1970
0
Anyone care to decode the knob legends
Vc,Vf,F,C,A,S

Vc was on the 6 way timebase switch, I am assuming it was moved from the
least used or easiest to turn without a knob
Gueses S for Sync, A for attenuation, F for Fine, C for Coarse , Vf for
focus but Vc ?
 
G

Geo

Jan 1, 1970
0
Anyone care to decode the knob legends
Vc,Vf,F,C,A,S

Vc was on the 6 way timebase switch, I am assuming it was moved from the
least used or easiest to turn without a knob
Gueses S for Sync, A for attenuation, F for Fine, C for Coarse , Vf for
focus but Vc ?

Vc is cathode voltage - probably the brilliance control
Agree Vf for focus.
F could be (timebase) Frequency?
 
J

John Robertson

Jan 1, 1970
0
I have a CV320 tube that has a pale green screen and might possibly work
as a replacement for your tube. I have not checked the filament for
continuity, but the tube 'looks' fine...

John :-#)#
Vancouver, Canada.

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


--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
 
N

N_Cook

Jan 1, 1970
0
John Robertson said:
I have a CV320 tube that has a pale green screen and might possibly work
as a replacement for your tube. I have not checked the filament for
continuity, but the tube 'looks' fine...

John :-#)#
Vancouver, Canada.




--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."



I would be interested, different pinning, no problem, otherwise much the
same specs
http://www.r-type.org/exhib/aaa0831.htm

is your valid email address really spam and then the things sharks and
pinball m/cs have .com
 
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