Looking for manuals or schematics for a goldak model 101

[AndrewBaker]

hello everyone, I come from an antique radio forum with a goldak two box metal detector and I would like to get it working, it is the model 101. but, I cannot seem to find any documentation for it.

[Skippy]

Does it mention any patent numbers on it ? They may give clues to its operating technique.
Are we to assume it's 1960's /70's technology, so transistorised ? Or is it thermionic valve-based?

Update: thanks to a French blogger, here is the Model 101 two-box machine:
https://detecteurmetaux2.blogspot.co...01-goldak.html

The mention of grid bias cells ( that last indefinitely ..... ! ) means it has to be valve-based.

Here's the patent, from 1939:
https://www.geotech1.com/pages/metde.../US2160356.pdf

https://patents.google.com/patent/US2160356

[Skippy]

This page on the similar-looking 'Terrasonic' machine has a photo of a brief instruction guide:
https://detecteurmetaux2.blogspot.co...-1-goldak.html

Different Patent link:
https://patentimages.storage.googlea.../US2160356.pdf

Having looked at the patent, it gives quite a lot of detail, that could help get it going again. But beware, metal detectors are not simple instruments, even in the 1940's it would take some careful work to get results.

[Carl-NC]

You'll also need to build batteries for it, the original types are long obsolete. The plate battery is typically 67.5V which can be made with series 9V batteries.

[Skippy]

I assume obsolete batteries is an everyday issue for vintage equipment restorers, I'm sure there's an easy solution for all these cells, maybe switching regulators for the HT supplies?

Some photos of this beast would be interesting to see.

[Stevedbk]

See Andrew, I told you Geotech would help.
This is the OP info on ARF.
https://www.antiqueradios.com/forums...p?f=2&t=414654.
Good luck, I hope you get it working.
Steve

[Skippy]

Andrew doesn't seem that interested ...

[Skippy]

I've just taken another look at the 'Antique Radio Forums' link posted earlier.
On the 15th July, Andrew posted:
"People on the Geotech Forums couldn't find much. it is a relatively simple device so I will just play with it to see what I can get it to do."

Nice to see our efforts appreciated!

[68Andy]

Just gossip with no backgroundPeople laugh at such people or ignore themOf the efforts, the serious users get the greatest benefits here

[AK48]

if it would help