A1200 Wrong Colors

[Retrofan]

Hi:

This is my "new" 1D1 mobo that I recently fixed repairing a problem with the joystick. It shows too much blue, so the icons are like violet.



This is using Amigakit's scart, that works perfect with the other Amigas.

What can it be? Caps? I cleaned the pins of the connector and I thought it was ok, but as you can see it isn't.

[clauddio]

lack of green
check around the sony chip for small ceramic caps and resistors in bad state

[Retrofan]

Originally Posted by clauddio

lack of green
check around the sony chip for small ceramic caps and resistors in bad state

Nice, but no idea which is the sony chip:



Or here: http://amiga.resource.cx/photos/phot...res=hi&lang=en

Well, I don't have any cable soldered like in that photo in the chip ADV10

[jimbob]

Sony chip is U12 to the left of IDE connector.

Are you using RGB->SCART cable? I had the idea that this chip was not related to RGB output, only RF and composite?

[clauddio]

the sony cxa1145 near the ide connector (24 pins)
RGB lines pass through there and are amplified by the chip,and they end up in the 23 pin video port

[Retrofan]

Yes, I had the Ide cable over it, so I didn't see it.

But I don't see anything wrong:



I can do any amplified photo, with an usb microscope that you ask me.

[clauddio]

Originally Posted by jimbob

Sony chip is U12 to the left of IDE connector.

Are you using RGB->SCART cable? I had the idea that this chip was not related to RGB output, only RF and composite?

pins 21 22 23 are RGB outputs,the chip is there to amplify the lines,for RF and composite video
the chip also offer SVHS if you do a little circuit

[cpiac64]

i repaired one with same defect, remove C216 10uF near ide port and verify continuity of 3 wire go to under cxa

[Retrofan]

Originally Posted by cpiac64

i repaired one with same defect, remove C216 10uF near ide port and verify continuity of 3 wire go to under cxa

So C216 out? Or do I replace it with another?

[cpiac64]

sorry, c219 ? don't remember, look chip cxa, you can look 3 wire at the right from transistor.
sorry find a photo and modify for more info

[Retrofan]

It seems cap 21(4)¿?

[cpiac64]

sorry i am mistake with a600, verify color form rf or composite, test R232a, R232b and R232c 24.9ohm

Originally Posted by Retrofan

It seems cap 21(4)¿?

yes in my a600 one of the 3 wire under C21? are broken, but i verify schematics a1200 1d? is different

[Retrofan]

Before I'll start desoldering and changing them (I can't check them) I've got a doubt. When I got the mobo I was trying to repair a joystick problem, and apart of a chip I changed, I found another thing in the mobo, that I repaired. Now I'm not sure if the Amiga had this colors before.

The smd I repaired was R370C. Has it something to be with the colors? I mean, perhaps it doesn't need that piece.





Edit: Well, here it has it: http://amiga.resource.cx/photos/phot...res=hi&lang=en

[keitha1200]

I had a similar problem in the mid 90s with my 1200 but the problem was with the 'grey' having a slight 'pink' tint to it. I sent to a repair place (advertised in AF) and they told me it was a 'dry solder' problem.

I believe the problem happen, after my 1084 was knocked over, and the 1200 went 'flying' and was suspended in mid air (via the monitor lead). probably not much help, but you never know.

[Retrofan]

I've checked searching for dry joints, resoldering all, broken traces, nothing.
I desoldered my replaced smd and nothing. Now soldered again.

Can't it be just the Sony chip? I could try to solder another from a donnor. If you don't say no I'll try tomorrow.

I've tried with the RF but coudn't watch it (perhaps had to change something of my Tv, dunno). With the Composite I have first this:



And this at the end:

[Retrofan]

I've changed the Sony chip with a donnor, but the result is exactly the same; not better, not worse.

Perhaps I can't fix it.

[jimbob]

Hi, your pics of the composite output look to have an opposite colour problem. ie. green is back but now red is missing.

Maybe a trick of the light but maybe a clue? At least you have probably eliminated the sony chip as the cause.

Also, I don't have A1200 schematics so I don't know what R370C is for. But it looks from the photo like you may have a solder bridge between the left side of that resistor and the via just below it. Maybe it is meant to connect there?

[Retrofan]

No, R370C is at the other side of the board, far away, and I don't think it can be related. And there's no trick of the light, it's like that, yes rare to me too.

I'll try to change R232a, R232b and R232c as cpiac said.

Edit: No, I can't. My Amiga for spares hasn't them. I'm now writing to Amigakit to see if they can fix it.

[Magno Boots]

Just may be worth using the Anemos trick?..



I cannot locate the exact thread at the moment, but I had a board that was showing as pink and this mod worked with the LED alone.

No harm in trying.

[FOL]

Originally Posted by Magno Boots

Just may be worth using the Anemos trick?..

Attachment 31874

I cannot locate the exact thread at the moment, but I had a board that was showing as pink and this mod worked with the LED alone.

No harm in trying.

hehe, mine has this issue. Just never have any time to fix it, .
Dont really notice, aslong as I can play games on it, I dont worry.

@Retrofan

If its wrong on both rgb and compsite, then it could be related to bt101 U30. Or a component linked to sony chip and U30.