GPO Detector No3 Does anyone have any information.
 

A friend has recently given me a GPO test meter which I understand from posts on the forum was known as Detector No 4, I also have a couple of very early GPO meters which are labelled GPO No2 which date back to at least the early 1920's, presumably there would have been a number 3 meter, I was wondering if anyone has any information or has one of these? I'm assuming the first GPO meter would be one of those Q & I Detectors in a wooden case.
Mike.

Re: GPO Detector No3 Does anyone have any information.
 

Didn't always work logically with the GPO! The 'Vocabulary of Engineering Stores' from the early 1940's doesn't show a 'Detector No 3' . The No 2 is listed but not available to order. The No 4 was the current one from the early 1930's through to the 1950's.

GPO naming/numbering wasn't always logical. For instance the first version of an item wasn't the 'Mark 1' version. It was the 'Mark 234', with the second one being 'Mark 235' then 'Mark 236' etc. When it came to telephones, table ones had even numbers and wall ones had odd numbers. As there were far more models of table telephones than wall ones, there are plenty of gaps in the odd numbering. Plus there are huge gaps, where are the 400, 500 and 600 series of telephones?

Ian J
CNet 0352 2345/01-432 1234
MR ETD 053-6278

Re: GPO Detector No3 Does anyone have any information.
 

I'd query the No4 dates. My TO mentor in my home area had one in his tool kit , from memory ain a black plasticy case. He took great delight in teaching me about it's use, especially for finding HR faults and it's benefits over the 9083.
I remember the circuit of a Det4 being discussed on either my "A " or "B" courses in 1966 and 1967 to explain how meters worked and how to calculate series and shunt resistance with the emphasis on high resistance input meters.
And again as in the last post where are the 400/500/600 series phones.
Even this shows a gap in the numbering
https://www.britishtelephones.com/telelist.htm

Possibly like the gaps in numbering the Det's ,new versions of the phones could have designed and trialled but not found suitable.

Re: GPO Detector No3 Does anyone have any information.
 

Assuming that the information about the date of davidw's No4 in the post by noble kiwi (GPO Portable Voltmeter) the meter I have is from 1966 ( Front Label "4GPO TRA/66").
Mike.