Dragon transformer

[norris]

Repair or biuld a new one?

[paul]

Dunno.

I've got the same problem. I have a working transformer, but I'd like another one for my other Dragon (my teen son wants to mess around with it).

I'm struggling to find an (affordable) new one.

I can get a suitable transformer for about £40 and wire it up and put it in a case, but £40 is quite expensive.

It'll probably be cheaper to get a couple of transformers (one 8.5V and one 2x14.5V) and put them in a case together.

Unless someone knows a cheaper supplier of a 8.5V+2x14.5V (or similar) single transformer.

OTOH, repairing a transformer is quite hard, so if you're asking the question, it's probably not something to do...

(Potentially another alternative would be to use a PC SMPS and wire it directly to the main board, bypassing the power board in the Dragon, but I'm a bit reluctant to do that.)

[tormod]

This question comes up from time to time. There is a replacement transformer solution in the wiki http://archive.worldofdragon.org/index. ... upply_unit
also discussed here: viewtopic.php?f=5&t=3416

This thread was originally about CoCo2 but has a lot of interesting information viewtopic.php?f=8&t=4947
and led to this viewtopic.php?f=8&t=4967

[paul]

Yep, that's the transformer that's about £40... (At least it is, anywhere I can find which will ship to the UK)

[sorchard]

It'll probably be cheaper to get a couple of transformers (one 8.5V and one 2x14.5V) and put them in a case together.

Possibly a lot cheaper:

http://uk.farnell.com/pro-power/ctfcs6- ... dp/1780871

http://uk.farnell.com/multicomp/vtx-146 ... dp/1675050

Would suggest checking the supply currents before parting with money in case the transformer ratings are insufficient.

If the 5V reg runs too hot then the 9V can be dropped a bit with anti-parallel diodes.

[fridgemagnet]

I've modded (upgraded?) all of the power supplies on my Dragon's by replacing the internal regulator board with a small switch mode PSU (which generally are in the same price bracket as the £40 you'd pay for a new transformer). Advantage is that it gives cleaner supply rails plus has a bit more juice available for running additional disk controllers/other hardware etc.

[paul]

I can't find any reasonably cheap SMPS which do -5V. Does yours, or are you using a -12V to -5V converter/regulator to get the -5V?

Eg, something like this

http://www.ebay.co.uk/itm/DC5V-12V-12V- ... 2103205e23

[tormod]

fridgemagnet, pics or it didn't happen

paul, maybe Jon had modded a Dragon 64 which takes -12V and not -5V on the motherboard.

[fridgemagnet]

For those doubting Tormod's out there...

IMG_20150928_202010.jpg (223.94 KiB) Viewed 5192 times

That is this little beast in a D64:

http://uk.farnell.com/webapp/wcs/stores ... reId=10151

I filed out the hole which housed the original switch and fitted a spare rocker I had on the mains side.

However Tormod is correct, for a D32 the -5V rail is the issue and these aren't so readily available at least at the same price. In the end, I did pay a bit more & fitted one of these:

http://uk.farnell.com/webapp/wcs/stores ... reId=10151

Ultimately a bit of a trade off between making up a convertor yourself or just paying a bit more, in this instance I did the latter.

NB: Watch out for the prices on Farnell's site as they don't include VAT!

[tormod]

I'll believe you the day they find water on Mars...

There are some cheap switched PSUs on aliexpress (search for t-30a), but I don't know how well they would work. Search t-50a for more watts.