Alba 7070 stereogram - Page 3 - UK Vintage Radio Repair and Restoration Discussion Forum

SiriusHardware · 13th Feb 2019, 11:58 am

Also - it may be heresy to suggest this, but you could always use a dual - output switch-mode PSU like this:

https://www.ecopacpower.co.uk/rd-50b.html

That one is likely to be expensive but you can probably find equivalents cheaper in the usual places.

The scale lamps would run OK on 5V out and the radio / amplifier would run on the +24V output.

Apart from finding the space to fit it, one other potential problem might be RF interference from the PSU to the radio.

kirstyd · 13th Feb 2019, 8:32 pm

I dont think the burned out transformer is original .Extra holes have been drilled where it sits suggesting alterations at some time and i certainly dont want to go to the expense of having it rewound .if i continue to use the 16 volt winding to power the unit could i not use the 24 volt winding for the lamps and just fit two 12 volt bulbs ?

SiriusHardware · 13th Feb 2019, 8:35 pm

Absolutely.

...As long as the lamps are wired in series and not in parallel. If in parallel, then you need 2 * 24V bulbs. Try to keep the wattage the same, or as near as, that of the original bulbs since that will give you roughly the same brightness as the 6V bulbs. They'll run on higher voltage but draw less current than the 6V originals for the same amount of watts out.

13th Feb 2019, 11:58 am	#41
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,586	Re: Alba 7070 stereogram Also - it may be heresy to suggest this, but you could always use a dual - output switch-mode PSU like this: https://www.ecopacpower.co.uk/rd-50b.html That one is likely to be expensive but you can probably find equivalents cheaper in the usual places. The scale lamps would run OK on 5V out and the radio / amplifier would run on the +24V output. Apart from finding the space to fit it, one other potential problem might be RF interference from the PSU to the radio.

13th Feb 2019, 8:32 pm	#42
kirstyd Heptode Join Date: Mar 2014 Location: Leeds, West Yorkshire, UK. Posts: 902	Re: Alba 7070 stereogram I dont think the burned out transformer is original .Extra holes have been drilled where it sits suggesting alterations at some time and i certainly dont want to go to the expense of having it rewound .if i continue to use the 16 volt winding to power the unit could i not use the 24 volt winding for the lamps and just fit two 12 volt bulbs ?

13th Feb 2019, 8:35 pm	#43
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,586	Re: Alba 7070 stereogram Absolutely. ...As long as the lamps are wired in series and not in parallel. If in parallel, then you need 2 * 24V bulbs. Try to keep the wattage the same, or as near as, that of the original bulbs since that will give you roughly the same brightness as the 6V bulbs. They'll run on higher voltage but draw less current than the 6V originals for the same amount of watts out.