💾 Archived View for uscoffings.net › retro-computing › systems › Tandy › oldskool › monomod.txt captured on 2024-02-05 at 11:31:50.
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TANDY 1000 Monochrome Modification ==================================== If you use a VM-2, VM-4 or some other composite monochrome monitor with a TANDY 1000 then you will know how a lot of programs show some colors in an annoying dot type pattern instead of the expected smooth shades of gray. This occurs with both text and graphics displays, and you have to keep continually adjusting the brightness and contrast controls, this can end up with alot of the text or graphics not readable at all. The reason for this is because the video port is designed to work with a composite color monitor, and thus has a composite color signal mixed with the RGBI and sync lines wich are then combined to produce the final video output. Therefore the problem is easily fixed by simply removing the composite color signal. This is done by removing or cutting one leg of resistor R55, which is located in a row of 10 resistors right of the motherboard power connector. The bottom resitor in the row is labled R53, therefore the third one from the bottom is R55. It should be a 750 ohm resistor , but mine was in fact a 1.2 Kohm. R55 can just be removed or cut from the board, but I added a switch in series and mounted it on the front panel, this will allow you to change between Mono and Color mode at any time without crashing. This can be very handy because some programs do actually look better in the Color mode. You should now find that you can get 16 shades of gray (Green actually!) without that annoying pattern and that with the right combination of the brightness and contrast controls, they will all show up on the screen at once. This can look very effective especially with the programs that utilise the Tandy 16 color graphics mode. by David L. Jones TRONNORT Technology EMAIL dljones@ozemail.com.au WWW : http://www.ozemail.com.au/~dljones