Some problems with Dragon 64

[JoeMorgan]

Hey guys, again!

Here I am with a problem: What the hell could be wrong with this Dragon 64? (Yes, the gift from my wife )



Spanish "Eurohard" Dragon 64 (PAL?) conected via composite on PAL TV.

Symtoms:

1st.- I connect the power and the computer turns on and displays the usual screen ... in black and white!
2nd.- It gives me time to program a "Hello World" program with loop. It run and takes a minute to crash. Frozen screen.
3rd.- Pressing reset shows me a blank screen. Still frozen.
4th.- Until I extract the connector from the power supply and connect it again I can't see again the usual splash screen.
5th.- This time, the computer gives me 10-15 seconds to operate. Frozen screen.
6th.- GOTO 3rd.-

Capacitors, power supply? Where I can start?

Thank you in advance for your help.

Joe Morgan

[robcfg]

I think the black and white display means that you have a NTSC machine.

Also, the screen looks quite like a square, pretty much like a NTSC signal on a PAL TV.

As for the machine freezing, I'm all in for damaged capacitors.

Please take some pictures of both boards in your machine.

Cheers,
Rob

[Alastair]

Rob, did Eurohard ever make an NTSC Dragon? I was under the impression that all NTSC Dragons were made by Tano.

Joe, welcome to the forum. I can't offer much help with fixing your Dragon but I do wonder if you have tried using an RF cable and tuning in the TV to see if you get colour. Also you state, "Until I extract the connector from the power supply and connect it again I can't see again the usual splash screen." Does this mean that your Dragon doesn't have an on/off switch (if the switch round the back is labelled Channel 3/4 then your Dragon is definitely an NTSC machine), the switch doesn't work, or that toggling the switch doesn't present the splash screen?

[robcfg]

I know of several people with Eurohard Dragons with NTSC boards.

Must have been to cope with demand or to get rid of stock...

[JoeMorgan]

Hi again!

@Alastair
Yes, exists a rounded switch labelled Channel 3/4 and I've understand like that (Ups!, I haven´t used as a power switch ... ). I was unable to try yet. I'll do it.
Yes, I tried to connect RF with the same result. Colorless.

Thanxs.

@Rob
You think Eurohard sold NTSC Dragon in a PAL signal country?

To try to resolve this doubt, I attached some photos.




http://i68.tinypic.com/1zb8i8w.jpg


http://i64.tinypic.com/2ihb5fp.jpg

Another clue that I should give you (I thought it wasn´t relevant) is that the power supply I use is for Dragon 32.

Thanks in advance!

Joe Morgan

[robcfg]

I was right!

Your motherboard is a Tano NTSC board!

Check the board number here, in our motherboard scans section.

Try your machine on a TV that supports NTSC to check if the image keeps disappearing.

The PSU is no problem, as it's the same for both machines.

[JoeMorgan]

It's crazy but it's true. The motherboard is a Tano Issue 2.
What purpose did sell those computers where no TVs that accept NTSC signal?

I broke the seal of guarantee! It's genuine.

I´ll try on a TV that accepts NTSC and I'll inform you.

I guess first problem solved. We will continue investigating why freezes.
If somebody needs pictures in more detail, you need only ask. I´ll try check the state of capacitors and the PSU values.

Thanks!

[robcfg]

Maybe they sold the remaining stock with NTSC monitors as a bundle...

I'd try first the machine on a TV set that supports NTSC, and then if the freezes continue, I'd look for another Dragon user nearby and I'd replace the socketed chips with the ones of a working Dragon, and see if that fixes the problem.

Otherwise I'd replace the capacitors. First from the porwe board and as a last resort, from the motherboard.

[JoeMorgan]

Hi again! Here I am with more data to share,



from top to bottom (regulators pins):

-11.90V
-18.20V
0V

+11.85V
0V
+18.21V

Do you see correct voltages?

Thanks in advance!

Joe Morgan

[robcfg]

The output voltages seem Ok.

Can you test the 5V regulator output?

5V_Regulator_Pins.jpg (49.12 KiB) Viewed 4247 times