UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Amateur and Military Radio

Notices

Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

Closed Thread
 
Thread Tools
Old 19th Oct 2018, 5:50 pm   #1
G8BBZ
Pentode
 
G8BBZ's Avatar
 
Join Date: Oct 2005
Location: Hebden Bridge, West Yorkshire, UK.
Posts: 199
Default Pye VC290/24 voltage converter

Hi All,
I have a couple of these units, which I believe to be 24v to 12v converters, possibly of Westminster vintage. I was surprised to discover that the unit contains an inverter type converter, not just a dropping resistor as I had expected.
I haven't been able to track down any manual info on these units, and hope that somebody can tell me how much current they will deliver at 12v - if they are Westminster accessories they should be good for 5A or so I would think.
__________________
Peter G8BBZ
G8BBZ is offline  
Old 19th Oct 2018, 6:11 pm   #2
Jon_G4MDC
Nonode
 
Jon_G4MDC's Avatar
 
Join Date: Nov 2015
Location: Welwyn Garden City, Hertfordshire, UK.
Posts: 2,013
Default Re: Pye VC290/24 voltage converter

Actually they are later - mid 1980s for M290 and MX290 series.
Yes they are a switcher. I would expect 5A perhaps some more.
They will have current limit or shutdown, try it out
Jon_G4MDC is online now  
Old 20th Oct 2018, 8:04 pm   #3
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,951
Default Re: Pye VC290/24 voltage converter

I have memories of these fitted in cattle-haulage trucks in the very-early-90s, powering VHF high-band MX290s.

One truck regulary came back from continental trips with the radio not-working and the 24-to-12V brick dead.

Turned out that the driver in question had worked out how to disconnect the MX290 and hook up his 12V-powered portable-TV to the output of the dropper. It was a 17-inch colour-portable so expected quite a few amps when running off 12V; more than the Pye dropper-brick could reliably provide for hours at a time.
G6Tanuki is offline  
Old 21st Oct 2018, 11:26 am   #4
Jon_G4MDC
Nonode
 
Jon_G4MDC's Avatar
 
Join Date: Nov 2015
Location: Welwyn Garden City, Hertfordshire, UK.
Posts: 2,013
Default Re: Pye VC290/24 voltage converter

Interesting tale, so no current limit and possibly no over temperature protection is suggested. That is disappointing.

I have never taken much interest in them (no 24V environments) but I will be looking for a circuit too now!

Last edited by Jon_G4MDC; 21st Oct 2018 at 11:39 am.
Jon_G4MDC is online now  
Old 23rd Oct 2018, 10:07 pm   #5
G8BBZ
Pentode
 
G8BBZ's Avatar
 
Join Date: Oct 2005
Location: Hebden Bridge, West Yorkshire, UK.
Posts: 199
Default Re: Pye VC290/24 voltage converter

Thanks for the replies.
The units do seem to be very simple - a pair of TO-3 power transistors as oscillator,a ferroxcube transformer and a couple of meaty rectifier diodes. No stabilisation, no current limit.
Nice story about the cattle trucks.
If a circuit does come to light I would welcome a copy.
__________________
Peter G8BBZ
G8BBZ is offline  
Old 24th Oct 2018, 10:32 am   #6
Jon_G4MDC
Nonode
 
Jon_G4MDC's Avatar
 
Join Date: Nov 2015
Location: Welwyn Garden City, Hertfordshire, UK.
Posts: 2,013
Default Re: Pye VC290/24 voltage converter

That is surprising Peter, next will you say the TO3s are marked NKT404!?
(Re-hash of Pye Cambridge Inverter)
Jon_G4MDC is online now  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 2:50 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.