Tester SA9004

[Dickie]

This isn't really in my area of interest, but does anyone know anything about this? A google search produced nothing. Clearly it's some sort of line fault tester, but what vintage, usage, how common etc? It's in a very battered wooden box so its not very desirable unless its a museum piece. The ID plate on the outside says "TESTER SA9004, DGM SA9004B"

[Pellseinydd]

GPO "Vocabulary of Engineering Stores" gives it as
"Portable tester for ascertaining distance of connexions of condrs. in lead covered cables - Includes -
1 Coil Induction No 12
1 Rec H.G. No 10A Double with Plug 316B
1 Jack No 800B6/N
3 Labels No 21, Blk
1 Res.Coil, No 12 - 1000ohm (specially adapted)
1 Potmr., 1,000 ohm (Berco. Type M)

To be requisitioned sep. :- 2 Cells, Lec., DS 5 "

Dated mid 1950's .

Can't give much more than that

[Herald1360]

That should polish up nicely, guv

Seriously, a wipe down with white spirit and a quick polish will improve it no end. It probably isn't worth stripping and revarnishing, though.

It appears to be a rudimentary capacitance bridge type of unit, balancing the capacity to sheath of the good wire plus far end of bad wire against that of the bad wire near end.

[Pellseinydd]

Originally Posted by Pellseinydd

GPO "Vocabulary of Engineering Stores" gives it as
"Portable tester for ascertaining distance of connexions of condrs. in lead covered cables

Dug a bit deeper - it is also in the 1944 'Vocabulary of Engineering Stores' so goes back even further than the 1950's.

[Dickie]

Thanks both, I don't think this one is that old

I've taken it out of the case to look for some dating evidence and it seems to have a transistor in it! The box marked "oscillator no.85A" contains a pot core transformer and a few other components and something that looks very much like a Mullard OC series transistor, only not quite. It has three leads in an OC style black painted encapsulation but is longer and thinner than usual. Perhaps it's a GPO special? It's leads are also brought out to pins on the outside of the case, maybe it wasn't very reliable.
The PVC wiring sort of gives the game away, as well

Also see a picture of one of the batteries, which clearly isn't one of " 2 Cells, Lec., DS 5"

[russell_w_b]

April 1967 for the 1.5V cell?

We in what was BBC Transmission were still using wooden-encased instruments in the 1980s (odd times). Still a few knocking around!

[Pellseinydd]

Originally Posted by Dickie

I've taken it out of the case to look for some dating evidence and it seems to have a transistor in it! The box marked "oscillator no.85A" contains a pot core transformer and a few other components and something that looks very much like a Mullard OC series transistor

'Oscillator 85' is much later - it was still being listed in the mid 1980's as
"Transistor Oscillator Assembly for portable eqpt. Output 10mW max (See diag SA 9140) Operated from 4.5 to 6.0 v DC"
- two versions -
1B 1 kc/s
4B 400 c/s.

Knowing the way the GPO/PO worked, their kit was often 'reworked' in the PO Factories to update it.

Ian

[Dickie]

Thanks. I don't think I can justify space in my collection for this, so it will probably appear on the B&B stall at Harpenden (unpolished!).