Hi
I came across an Amstrad 464 Plus motherboard and decided to "revive it. After starting it works, but there is a problem with the RGB output with image quality.
The image looks like the first photo, it is probably missing some color component, and there are ghosts in the image that can be seen in the text.
For comparison, the image should look like the second photo.
Does anyone know where to start looking for the cause? Is it possible that one of the passive elements has lost its parameters?
Do you have a way to see it on a CRT? Maybe the image jumps up and down and the LCD binds it into ghosts.
Hi,
from your pictures, there's absolutely nothing wrong with the CPC. The colour issues are due to the converters interpretation of the RGB values. Most good converters will have potentiometers to adjust these to the correct colours and the ghosting is also an artifact of the conversion. Don't change anything on the CPC, it's fine. If the converter can't tune the colours or it produces this much ghosting, you just need a better converter. However, you didn't mention which converter you used.
As Arti0 rightly questioned above: What does it look like on a CRT?
Bryce.
I don't have CRT.
I don't use any converters. I have conected RGB directly to LCD TV by SCART.
My second Amstrad 464 Plus working fine on the same LCD TV.
Check capacitors near the transistors of mixer video signal.
I just did this and the RGB output is now almost perfect. I replaced 5 capacitors with new ones near the video output.
However, there is small ghosting left. How to repair this?
disconnect the luminance in scart and see if anything improves.
Quote from: McArti0 on 07:27, 20 July 24disconnect the luminance in scart and see if anything improves.
I have a cable according to this scheme. Which pin should I cut off? Pin 20 ?
disconnect 3-20
connect 1-20
When I connect 1-20 there was only gray picture and shadow of text (image1). When I add +5V with 180R to pin 16 there was nothing change. When I connect 3-20 the picture was in grayscale but clear (image2). When I add 3-16 picture was in full color with a little shadows. If I connect the same config to OSSC picture is clear with or without pin 16 in scart connected (image3). Tested on two Amstrad boards 464 Plus I have. So I stayed at it. Maybe my 2 retro monitors on scart port are not perfect.