Dragon 32 black and white output

[brendan1495]

Hi All,

I am trying to repair a Dragon 32 everything works fine but its in black and white. I have tried changing the pots but still the same, I have also resocketed and changed the LM1889 but no difference. Any ideas were to go from here would be appreciated.

Brendan

[robcfg]

Hi Brendan, welcome to the Dragon Archive!

Can you check your motherboard and tell us which part number it has written on it?

Cheers,
Rob

[brendan1495]

Hi,

This is the board

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[robcfg]

Ok, according to the service information, this is what you could try:

C. Faulty Colour
1. Adjust RV1 (and RV2 if fitted).
2. Alter value of C7.
3. To obtain full green screen or to cure 'rainbow effect', fit a 2-22 pf capacitor trimmer instead of C7.
4. If colour fault on 22" or 27" SONY sets, then fit 15K resistor across Pin 4 of IC9 to Pin 4 of IC10.
5. Change IC9.
6. Change IC16.
7. Change IC12.

Are you connecting it to an old TV, new TV or to a capture device?

[sixxie]

And check your voltages! Other way around, but I accidentally powered a D64 from a D32 PSU board before which led to no proper -5V and the most obvious symptom was no colour (and tbf pretty shonky video generally, but it was there).

[robcfg]

That's a good thing to check!

Brendan, do you mind taking pictures of both sides of the power board?

[brendan1495]

At work at the moment will do when I get home

[brendan1495]

And check your voltages! Other way around, but I accidentally powered a D64 from a D32 PSU board before which led to no proper -5V and the most obvious symptom was no colour (and tbf pretty shonky video generally, but it was there).

Will check, thanks

[brendan1495]

Ok, according to the service information, this is what you could try:

C. Faulty Colour
1. Adjust RV1 (and RV2 if fitted).
2. Alter value of C7.
3. To obtain full green screen or to cure 'rainbow effect', fit a 2-22 pf capacitor trimmer instead of C7.
4. If colour fault on 22" or 27" SONY sets, then fit 15K resistor across Pin 4 of IC9 to Pin 4 of IC10.
5. Change IC9.
6. Change IC16.
7. Change IC12.

Are you connecting it to an old TV, new TV or to a capture device?

cnnecting to crt

[brendan1495]

That's a good thing to check!

Brendan, do you mind taking pictures of both sides of the power board?

I have modified the power board to use a meanwell, works fine on my other Dragon