Dragon 32 power supply help transformer required

[longboard1210]

I am in the proccess of restoring a coiuple of the dragon 32 machines from go old wales
the original power blocks were a three tap transformer and i am clearly not looking for the right thing because i cant seem to come up with anything
I would like to keep the internals the same and make new power bricks for them so if i find a proper one i havent got to undo anything i have done
according to the dragon 32 wiki page this is the transformer specs
55 VA, 8,5 VAC + 2 x 14,4 VAC

Could anyone point me in the right direction of trying to souce a transformer

Thanks
Mike

[barbeque]

Not sure your numbers are 100% right, I found this page:

http://dragon32.info/info/psu.html

They say 8.5VAC and 28VAC. I think the computer is only using AC so they can get negative voltages out (the power accessory board serves up -5V, +5V, +12V to the motherboard which I'm assuming is all DC).

28VAC feels oddly high if you are just trying to get +12VDC out of it (although it looks like the Dragon64 feeds -12VDC to the motherboard as well). Maybe they serve it to a user port for peripherals like on the C64?

[GadgetUK164]

I am in the proccess of restoring a coiuple of the dragon 32 machines from go old wales
the original power blocks were a three tap transformer and i am clearly not looking for the right thing because i cant seem to come up with anything
I would like to keep the internals the same and make new power bricks for them so if i find a proper one i havent got to undo anything i have done
according to the dragon 32 wiki page this is the transformer specs
55 VA, 8,5 VAC + 2 x 14,4 VAC

Could anyone point me in the right direction of trying to souce a transformer

Thanks
Mike

I did some repairs to a Dragon 32 last year - are you sure the transformer is dead?  If memory serves these have a thermal fuse that often blows on these.  You can remove the rivets from the PSU, find and replace the thermal fuse (check the temperature rating in the old one) and bring them back to life most of the time.  There are a few regulators onboard the Dragon : 5v, -5v,  and -12v (think).  You could add another power socket for a different PSU type, OR remove / modify the interal PSU board to use a pico PSU or something similar.

The windings are shown here:- http://archive.worldofdragon.org/images/4/44/Dragon_power_supply_schematics.png

Schematics for the onboard regulator section:- http://www.dragondata.co.uk/tech/circuit-diag/D32/SA/D32-SA21204-PSU-MOD.gif

You could in theory use an AC PSU that provides slightly different voltages there - just check which regulators are getting fed by the AC inputs.  Some modifications might need to be made if you do use another transformer.  If in doubt, disconnect the motherboard whilst you work on it.