RCA 18V100 Clock Frequency Adjustment Procedure, Ment, Scope Time-Base Locked to 60Hz Power Line

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nected with reversed polarity. Use fabricated tool (Fig. 28) to

push LED into holder. LED "clicks" into place. Any tool

without a shoulder usually pushes LED out of the holder.

7.Form snipped leadwires as shown in Fig. 31 and connect

new LED pigtails to them. Solder quickly to prevent over-

heating LED.

8.Reconnect black, white and yellow leads from PC board

to complete installation.

TO PC BOARD

BLK .WHT

CLOCK FREQUENCY ADJUSTMENT PROCEDURE

Incorrect clock frequency adjustment causes pattern weave

on screen. This results from a beat note between the vertical

sync rate of Studio II and the hum frequency in the TV re-

ceiver. If the beat note is more than 0.5 Hz, the weave becomes

noticeable to the critical user. Clock frequency is a slug adjusts

ment on the PC board.

1Connect scope probe to the junction of two resistors as

shown in Fig. 34. Connect scope ground to RF shield, cartridge

post or to other suitable board ground.

2.Adjust scope time base for a total sweep length of 20

milliseconds or more (sync on "Line") and vertical input

sensitivity for about 250 mV/cm (0.625 V/in).

3.Push "Clear" button on console and adjust slug slowly for zero waveform drift. See Fig. 33. Guard against overadjust-

ment.

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L,

V1WWVWWWWLW

f

(VERTICAL SYNC INTERVAL)

Figure 32. Power-OnIndicator Wiring	Figure 33. Waveform Used to Adjust Clock Frequency.
	Scope Time-Base Locked to 60Hz Power Line

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Figure 34. Scope Connections for Adjusting Clock Frequency

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