PSU Pictures

[Rolo]

Ok, I'm going to post a few pictures of mine. Unfortunately, the housing can't be opened up. They used eye-bolts.

[sixxie]

I quite like the separation of transformer and rectifier/smoother/etc.. In theory any one part dying would be easier and cheaper to replace or fix. In practice I've not seen many 28 & 8VAC transformers for sale!

[jedie]

btw. has anyone measured the consumption?
Because of Efficiency

[Rolo]

Ehhm, I'm failing to see the point behind that. What are you aiming at? Of course modern switched-mode power supplies have a better efficiency, that's well known. But who cares? It's just a handful of old computers pulling a few watts...

[jedie]

Just interesting.

btw. i must someday build a alternative power supply. Because i have 2x Dragon 32 and one Tano Dragon, but ony one origin 230V power supply.

[tormod]

I am interested in knowing the currents actually going to the motherboard. And yes, with an intention of dropping in a switching supply instead! Just saving a few watts and heat is one reason, another is the external PSU is heavy for transporting - I travelled with my Dragon to a vintage festival last weekend - OTOH this old square PSU really looks vintage though And the PSU is a bit in the way and it makes sometimes quite some hum. And it has a loose part inside rattling a bit, so I would prefer to not rely on it. I am also trying to get S-video output: If I could replace the whole power board with my own board with S-video connector and the switching supply instead of the DSUB power inlet, RF out and DIN video out it would be neat. I can always plug the old board back if I want later. BTW with a CMOS 6309 it would become a green Dragon

[tormod]

I quite like the separation of transformer and rectifier/smoother/etc.. In theory any one part dying would be easier and cheaper to replace or fix. In practice I've not seen many 28 & 8VAC transformers for sale!

Rolf posted a product link to a contemporary 28 & 8VAC transformer here: viewtopic.php?f=5&t=3416&p=8294#p8294

[sixxie]

So he did - I missed that. Good to know!

[jedie]

I am also trying to get S-video output: If I could replace the whole power board with my own board with S-video connector and the switching supply instead of the DSUB power inlet, RF out and DIN video out it would be neat.

Great idea!

[Rolo]

Well in that case, I'd really go for the smallest triple switched mode power supply I can get on ebay or in the shops (i.e MW T-60A).
If you look on the (SIEMENS-)schematics, you will find the required specs:
+5VDC: 1400 mA
+12VDC: 250 mA
-5VDC: 50mA
It's really easy to build such a power supply. All the components are quite common, but I'm not sure, if it's worth the effort.