A1200 no red ?

hello all..

im here to pick your brains!

My A1200 has a colour fault , i (think) the red signal has gone from RGB...

The kickstart logo is blue (3.0) it should be purple but the thing is ..if i connect an A520 modulator from an A500 and try it by tuning the TV , then i get the purple kickstart logo again.

The RGB lead is good, the tv is good, the power pack is good. everything has been tested in 3 different A500's and all is ok

any clues? bad caps, resistors , dead ic? , the roms are fitted down too.

help:help:

PS the colour was OK this morning but flickered a few times and then the colour became washed out looking...

for example

*the kickstart is blue - was purple
*the A1200 seems slower than usual
*if i play EPIC the ocean logo and writing is just white blocks
*stuntcar racer seems to run at half speed...

Does the A1200's built in composite phono and RF out sockets produce similar problems?

i cant say to be honest , the composite is so poor on my tv that i cant tell what colour it is...

but i think i may of found the fault , gentle push pulling of the power socket makes the screen flicker, so im just changing it!

tune in for the next up date!

---------- Post added at 21:04 ---------- Previous post was at 20:38 ----------

changed the power socket...still the same

however when the board is flexed slightly the colour changes

I'm not an electronics person, but maybe its dodgey solder on the connector to the motherboard? Maybe A520 might put enough pressure on the connection to get a good signal and cover the problem?

see if the colour comes back when you push down on the video dac (u30). It's the ADV101 chip just below the rgb connector. Pin 26 is the red output. (count pins anticlockwise)

hi hikey, no joy still a blue kickstart screen...

although pressing on the board makes it go more blue

@MJ

You need to change some capacitors on the board. I will get you a list in the morning.

i was starting to think that mr zetr0 ...thank you :-)

a list would be fantastic...at least the power socket is solid now ive soldered it back on lol

It doesn't look like a capacitor fault to me. in fact, the A1200 will display the kickstart screen with the correct colours even without any capacitors installed at all (although you will get interference on the screen).
The fact that you can change the fault by flexing the board indicates a soldering problem somewhere.

yes thats a fair comment

the colour has come back on properly on its own a couple of times but is back to blue now..