Dragon replacement power supply

[vdc300]

Hi

Sure I've asked the question a while ago, but just in case there has been any changes.......Has anyone found a suitable replacement to the dragon power supply, I remember it has some odd voltage requirements 28V and 8.5V AC, so not very "off the shelf".

Also, does anyone have a "spare" power supply, mine has gone pop (white type).

Thanks

[rolfmichelsen]

I had the same problem a while ago. My solution was to build my own replacement power supply. This is pretty simple and does not require significant engineering skills. The cost of the parts are about NOK 300 (GBP 30). I'm traveling right now, but I can add details with part list and assembly instructions next week if there is an interest.

-- Rolf

[vdc300]

Rolf

That would be great

thanks


Paul

[vdc300]

Rolf

I bought Stone Raider II in '86, was one of my favorite games. Well Done and Thanks.

[Alastair]

If your skills are up to it, you could try drilling out the pop rivets and removing the cover to see if the problem is anything obvious. With luck it may be something that is simple to repair. I'm not sure of the best way of re-securing the cover though: nuts, bolts, and washers from Meccano perhaps?

[prime]

If your skills are up to it, you could try drilling out the pop rivets and removing the cover to see if the problem is anything obvious. With luck it may be something that is simple to repair. I'm not sure of the best way of re-securing the cover though: nuts, bolts, and washers from Meccano perhaps?

If you do do this, remember to be very careful, and work with the power off, there are mains voltages in there that can kill.

Cheers.

Phill.

[vdc300]

Good News, kinda

After much deliberation, I just happened to twiddled with the lead coming out of the of the adaptor (28V side) and have found that if I loop the lead ontop of the adaptor and gaffer tape it down, I get power, so OK it's a lose or broken connection/wire near the exit point for the leads, and it will not hold forever, but I'll take it at the moment!

Cheers all for the advice.

FYI, I did find a 28V ac adaptor, it used to power a ZX81 printer (Alphacom 32) but not brave enough to create the 8.5V.

What where they thinking when dragondata selected this power supply option, was it just a rip-off of the COCO?

How I wish it was a lovely simple 9V/12V DC supply. I could run my D64 and D32 together.

Cheers

[rolfmichelsen]

Good that you managed to resolve the problem. I'll do the writeup of the DIY power supply someday, but I guess there is no rush at the moment. In your case, it's probably best to just replace the leads eventually.

I actuallt think the Dragon design is pretty good and typical for the time. The power supply basically just contains a transformer. This is the hot and heavy part and keeping it outside the case makes for a simpler design. Also, it is easy to swap when creating a model for a 110V mains circuit.

-- Rolf

[jmk]

FYI, I did find a 28V ac adaptor, it used to power a ZX81 printer (Alphacom 32) but not brave enough to create the 8.5V.

Be careful, make sure you get the polarity right way round!

I managed to break my original Tandy CoCo 2 16K by using an Alphacom 32 power supply. The big blue capacitor on the centre of the board burst, leaving a shower of oily fur all over the place.

[prime]

Good News, kinda
What where they thinking when dragondata selected this power supply option, was it just a rip-off of the COCO?

Like a lot of things it may have boiled down to 'we can get a bload load of these cheaper than any other option and they can be made to work so we use them'
I believe that was the major reason that Amstrads used 3" drives when virtually no one else did.

How I wish it was a lovely simple 9V/12V DC supply. I could run my D64 and D32 together.

Well, if you don't mind doing some surgery the main board of a Dragon does use standard voltages, +5, +12, -5, -12 and can be powered by a supply that
provides those. One gotya however is that the pin on the 32 board that expects -5, expects -12 on the 64.

Of course if you had a PSU that produced +/-12V, you could use the regulators on the power board to regulate for the +/5V.

Cheers.

Phill.