Mystery item from boot sale - UK Vintage Radio Repair and Restoration Discussion Forum

dragonser · 7th Oct 2022, 2:50 am

Hi, a neighbour got this from a boot sale, but what is it?

It seems to measure the AC current of an attached piece of equipment and also have a DC panel meter built in. It is very well constructed, wire looms being tied together.

dragonser · 7th Oct 2022, 5:15 am

Another pic..

Radio Wrangler · 7th Oct 2022, 7:37 am

I'd rate the construction quality as 'rather mixed'. There is some lacing of wiring, but the ends of the wires are left soldered to tags without any support such as heat shrink or Hellerman sleeves. It doesn't look to have been mechanically designed, rather things have been put where space was found inside the box. The parts inside are good quality. It has the look of a tester built quickly as a one-off.

It can measure mains current on either a 300mA or 1.5A scale with the moving coil meter.

It can measure mains voltage on the digital panel meter on a 400V AC scale.

It can measure DC voltage on the DPM on either 40 or 400V scales.

It looks like an application-specific tester for power supplies which are mains powered and output two different DC voltages, I'd guess 28v and 300v. from the scales

It doesn't seem to have any power loads, so it's just an output voltage check or adjustment it's for.

The mains current scales suggest a magnetising current check, and one with the DUT driving some not-included load.

I doubt you'll come across or need whatever it did, but there are some nice parts for building something else!

David

Electronpusher0 · 7th Oct 2022, 7:47 am

Also the mix of analogue and digital meters suggest a "one-off" built for a specific need.

Peter

The Philpott · 7th Oct 2022, 10:05 am

The poor quality plating on the steel facia screws is classic 'seventies Farnell, also the terminals and possibly the selector. The voltages might suggest testing chargers used for lorries and fork lift trucks..? That theory still leaves too many questions/functions unanswered.
Dave

dragonser · 8th Oct 2022, 8:44 am

Hi, thank you for all the comments. After looking again it seems the meter is made by sifam and will possibly be a replacement for the faulty one on the weir 400 psu I have. But as the old meter got fried, I need to work out how to put some protection on it I think...

David Simpson · 9th Oct 2022, 10:47 am

Peter, I'll echo David's advice regarding using this to build something else. With your extensive electronics background, and an interest in vintage valve technology - its measurement facilities could be "re-purposed" into a DC Valve Tester building project. It's too good to leave at the back of a dusty shed for yonks or dumped in a skip.

Regards, David

7th Oct 2022, 2:50 am	#1
dragonser Heptode Join Date: Aug 2009 Location: Carshalton, Surrey, UK. Posts: 734	Mystery item from boot sale Hi, a neighbour got this from a boot sale, but what is it? It seems to measure the AC current of an attached piece of equipment and also have a DC panel meter built in. It is very well constructed, wire looms being tied together. Attached Thumbnails __________________ Regards Peter B

7th Oct 2022, 5:15 am	#2
dragonser Heptode Join Date: Aug 2009 Location: Carshalton, Surrey, UK. Posts: 734	Re: Mystery item from boot sale Another pic.. Attached Thumbnails __________________ Regards Peter B

7th Oct 2022, 7:37 am	#3
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,867	Re: Mystery item from boot sale I'd rate the construction quality as 'rather mixed'. There is some lacing of wiring, but the ends of the wires are left soldered to tags without any support such as heat shrink or Hellerman sleeves. It doesn't look to have been mechanically designed, rather things have been put where space was found inside the box. The parts inside are good quality. It has the look of a tester built quickly as a one-off. It can measure mains current on either a 300mA or 1.5A scale with the moving coil meter. It can measure mains voltage on the digital panel meter on a 400V AC scale. It can measure DC voltage on the DPM on either 40 or 400V scales. It looks like an application-specific tester for power supplies which are mains powered and output two different DC voltages, I'd guess 28v and 300v. from the scales It doesn't seem to have any power loads, so it's just an output voltage check or adjustment it's for. The mains current scales suggest a magnetising current check, and one with the DUT driving some not-included load. I doubt you'll come across or need whatever it did, but there are some nice parts for building something else! David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

7th Oct 2022, 7:47 am	#4
Electronpusher0 Nonode Join Date: Jun 2016 Location: Bognor Regis, West Sussex, UK. Posts: 2,296	Re: Mystery item from boot sale Also the mix of analogue and digital meters suggest a "one-off" built for a specific need. Peter

7th Oct 2022, 10:05 am	#5
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,106	Re: Mystery item from boot sale The poor quality plating on the steel facia screws is classic 'seventies Farnell, also the terminals and possibly the selector. The voltages might suggest testing chargers used for lorries and fork lift trucks..? That theory still leaves too many questions/functions unanswered. Dave

8th Oct 2022, 8:44 am	#6
dragonser Heptode Join Date: Aug 2009 Location: Carshalton, Surrey, UK. Posts: 734	Re: Mystery item from boot sale Hi, thank you for all the comments. After looking again it seems the meter is made by sifam and will possibly be a replacement for the faulty one on the weir 400 psu I have. But as the old meter got fried, I need to work out how to put some protection on it I think... __________________ Regards Peter B

9th Oct 2022, 10:47 am	#7
David Simpson Nonode Join Date: Mar 2008 Location: Aberdeen, UK. Posts: 2,853	Re: Mystery item from boot sale Peter, I'll echo David's advice regarding using this to build something else. With your extensive electronics background, and an interest in vintage valve technology - its measurement facilities could be "re-purposed" into a DC Valve Tester building project. It's too good to leave at the back of a dusty shed for yonks or dumped in a skip. Regards, David