archive.worldofdragon.org

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

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!

btw. has anyone measured the consumption?
Because of Efficiency

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...

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.

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

sixxie wrote: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

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

tormod wrote: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!

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.