Board- Setting-up (Non-UK version) The only adjustment necessary on the RGB board is the setting-up of the Phase Locked Loop (PLL), a circuit which mutes the audio output in the absence of a valid video signal (i.e. no TV or AV).
(a)
Make sure there are no syncs applied to the input of the phase locked loop. This can be acheived by tuning the receiver to an unused channel (ie noise). Monitor II02 pin 5 with a frequency counter set to read kHz to 2 decimal places. First turn RI22 fully clockwise, then turn anti-clockwise to set the frequency between 15.45 kHz and 15.59 kHz, nominally 15.52 kHz. Check MI01 pin 6 is low (0~). Tune the receiver to a valid signal. Check that syncs are applied to the input of the P.L.L. Check that MI01 pin 6 is high (SV).
