Welcome to Australia's only Vintage Radio and Television discussion forums. You are not logged in. Please log in below, apply for an account or retrieve your password.
Australian Vintage Radio Forums
  Home  ·  About Us  ·  Discussion Forums  ·  Glossary  ·  Outside Links  ·  Policies  ·  Services Directory  ·  Safety Warnings  ·  Tutorials

Tech Talk

Forum home - Go back to Tech talk

 Traditional Battery Eliminator Thoughts
« Back · 1 · Next »
 Return to top of page · Post #: 1 · Written at 5:14:50 PM on 15 May 2022.
Lloydc's Gravatar
 Location: Pelican Waters, QLD
 Member since 31 March 2022
 Member #: 2495
 Postcount: 14

Hello,

I now have in my possession, two battery-powered valve radios, which first need to be repaired/refurbished and proven operational.

I have searched and found a few suppliers of circuit boards that once assembled will provide the various voltages, but I have been thinking of making up a box that will contain Li-Ion batteries powering two DC-DC converters.

One will perform in boost mode and provide the HT and the other will perform in the buck mode to provide the heater power.

Can anyone see any issues with this method?

Regards

Lloyd


 
 Return to top of page · Post #: 2 · Written at 5:53:26 PM on 15 May 2022.
Redxm's avatar
 Location: Tamworth, NSW
 Member since 6 April 2012
 Member #: 1126
 Postcount: 466

 
 Return to top of page · Post #: 3 · Written at 7:44:34 PM on 15 May 2022.
DangerousDave's Gravatar
 Location: Toongabbie, VIC
 Member since 1 September 2020
 Member #: 2438
 Postcount: 129

Yes, I have built 2 of the Silicon Chip types utilising 4x 18650 batteries. 2x for HT & 2x for filament supply. The units work very well with low noise and low battery cut out. They won't work with 9V filament supply requirements though. They are also compact enough to be housed in a box with the batteries contained and fitted into portable radios .I plan on building more when time permits.


 
 Return to top of page · Post #: 4 · Written at 9:29:27 PM on 15 May 2022.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

I have not really resorted to using battery based PSU's for oldies only a single voltage "No Break" for a scanner. Switch mode can be an issue with valve stuff.

I did build one a while back for 45V and 135V and 5V for 3 UX-201A's, One secondary was dedicated to the 5V filaments and a CPU fan to help a Heatsinked 7805 keep its cool. The other a 7905 for bias. Do be warned that both 5V regulators need a 1K load resistor. Step up from that winding was a reversed (salvage) transformer.

45V from an LR8; 135V from a second LR8. From the same "B" rail.

That was another plug in job so it could be used on other sets, in the guys collection.

Those little CPU fans can be quite handy for venting PSU boxes & other things.


 
 Return to top of page · Post #: 5 · Written at 5:12:17 PM on 17 May 2022.
Lloydc's Gravatar
 Location: Pelican Waters, QLD
 Member since 31 March 2022
 Member #: 2495
 Postcount: 14

Thank you all for your comments.

Yes, I am aware of the SC board and have one, I am still to source the parts and build it.

I guess I was just trying to shortcut the process, but as you mention, switch-mode power supplies can introduce their own issues.

Looks like I better order those parts. Smile

Thanks again.


 
 Return to top of page · Post #: 6 · Written at 6:45:24 PM on 17 May 2022.
Johnny's avatar
 Location: Hobart, TAS
 Member since 31 July 2016
 Member #: 1959
 Postcount: 543

Just as a matter of interest, I have a Philips battery radio that was repaired some months ago and then powered by a lash up of ten normal el cheapo 9 volt batteries and a couple of one and a half volt D cells.
Unit has been running for weeks at several hours per day in the work shop.
I feel for these restorations a built up battery box is a good answer.
Then, when later stored and batteries removed no real financial load is part of the radio. Just a neat battery box.
JJ


 
 Return to top of page · Post #: 7 · Written at 9:55:10 PM on 17 May 2022.
DangerousDave's Gravatar
 Location: Toongabbie, VIC
 Member since 1 September 2020
 Member #: 2438
 Postcount: 129

I feel your pain Lloydc, with sourcing the parts. With the interruption to global supply chains at the moment, it took me 3 months to source all the parts for this project from 4 suppliers. It's well worth it though as it does work well. The inverter switching is done at a low frequency so interferance is minimal. It's a shame these can't be bought as a complete kit with parts included. There's a lot of projects that SC design that I don't bother with because of the effort required to source all the bobs and pieces.

Modified Philips radio
Modified Philips radio
Modified Philips radio


 
 Return to top of page · Post #: 8 · Written at 10:35:32 PM on 17 May 2022.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

Once upon a time, some of the parts purveyors actually offered complete kits for you to assemble. DS Frequency counter is one of them.

MBVC


 
 Return to top of page · Post #: 9 · Written at 8:04:50 AM on 22 May 2022.
Brad's avatar
 Administrator
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 7290

Photos uploaded to Post 7.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 10 · Written at 6:16:23 PM on 23 May 2022.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2363

SC on-line shop now sells complete kits.


 
 Return to top of page · Post #: 11 · Written at 9:29:14 PM on 11 August 2022.
OldButLearning's avatar
 Location: Bunbury, WA
 Member since 4 August 2022
 Member #: 2513
 Postcount: 21

To 'Lloyd C' , Post #5, saying......
I guess I was just trying to shortcut the process, but as you mention, switch-mode power supplies can introduce their own issues

Yes, I'm building the same thing now. Quite a few old experienced guys on Youtube do warn against using and 'Switch Mode' gear with old radios, due to the interference/noise they can introduce!


 
 Return to top of page · Post #: 12 · Written at 11:27:34 PM on 11 August 2022.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

A classic here was a FAX using the House / Office, workshop phone line as an antenna & Its PSU getting into a 175kHz IF.

Marc


 
« Back · 1 · Next »
 You need to be a member to post comments on this forum.

Sign In

Username:
Password:
 Keep me logged in.
Do not tick box on a computer with public access.