ScuzzBlog: Diaries May 2020 Entry 16th May 2020: Post 1: Amiga 1200 fault - Green tint to screen. Amiga 1200 fault - Green tint to screen. I got so annoyed with the green tint to the grey on this one A1200 that I decided to pull the hard drive from her and stick in another of my 1200s. The screen has a faint green tint to the grey on the screen. The fault can be traced to the VIDEO-DAC chip VP101-3BA. There are six resistors associated with the DAC and Lisa that are of either 25 or 50 Ohms and it's worth checking those also. But most likely the VIDEO-DAC is at fault and needs replacing. You can buy these quite cheap from China even today on Ebay. To check the fault if you load up Pro-Tracker and go into the set-up you can use the RGB sliders to check the intensity of colours. With a green tint or failure of the blue, often there will be no change in intensity of the colour for half the bar. Then the colour grading will ramp up from only one half of the bar. The Red and Green kick in almost immediately you start the slider. Problems with the resistors generally cause a colour issue on the boot screen with the wrong colours displaying. A green tint on the grey Workbench screen points to the actual VIDEO-DAC. Fortunately I have a few replacements on old boards if I wanted to use them While I had the 1200 out I checked over all the capacitors. I rarely get troubled by capacitors. Haven't recapped any of my 1200s. So look out for VIDEO DAC BT101 or VP101 or something with 101. Just above the LISA top left. Or you could do what I did, and just call the poor thing 'BiaGreenie' and put up with it.... or not. V I D E O VIDEO-DAC Watch the sliders in ProTracker Amiga 1200 fault - Green tint to screen. The ProTracker software used. Screen with the grey tinted green. The ProTracker screen should be light blue. Use the slides to show the colour intensity. Comparing screens of faulty and good. Replacement on other motherboard. VIDEO-DAC schematic. Ebay prices for the VIDEO-DAC

If you can only see this CONTENT window
then click the image above for the full site

Last updated 16th May 2020

Chandraise Kingdom

Keep the Faith
scuzzscink 2020