Hi,

There are Commodore 64 computers in storage. If you have one or can get one,
it can be very useful as a service aid since it has an output which you can
connect directly to a TV. If you know Basic (see below), you can "program" it
to display various patterns.

This simple basic program produces all Red, Green, Blue screens, dots, and a
vertical line for TV purity and convergence checking. With a little knowledge
of Basic, it can be enhanced.

Symbols that represent quote mode characters in the actual C64 program
listing, which can not be produced here.

"@" = Clr Home (Shift & Clr Home keys) (shows inverted heart)
"|" = Solid vertical line (Shift and B keys)

"RGB ETC." filename example.

10 A=53280:C=2:B=0
20 PRINT"@ ANY KEY CHANGES COLOR"
30 PRINT" RED, GRN, BLU, DOTS, VERT LINE SEQUENCE"
40 GOSUB100
50 PRINT"@":GOTO90
60 IFC=2THENC=5:GOTO90
70 IFC=5THENC=6:GOTO90
80 IFC=6THENC=0:GOTO120
90 GOSUB160:GOSUB100:GOTO60
100 GETA$:IFA$=""THEN100
110 RETURN
120 GOSUB160
130 PRINTCHR$(5):PRINT"@";
140 PRINT" . ";:B=B+1:IFB199THEN140
150 GOSUB100:GOTO170
160 POKEA,C:POKEA+1,C:RETURN
170 PRINT"@"
180 FORI=1TO24
190 PRINTSPC(20)"|":NEXT:PRINTSPC(20)"|";
200 GOSUB100:C=2:B=0:PRINT"@":GOTO90

Brad

Before you type your password, credit card number, etc.,
be sure there is no active key logger (spyware) in your PC.