Fault Diagnosis And Repair - Colour, Repair And Upgrades; Ic14 (Lm1889) Pin Signals; 16K To 48K Upgrade - Sinclair ZX Spectrum Service Manual

7 F D
AULT IAGNOSIS AND

IC14 (LM1889) Pin Signals

Repair

16k to 48k Upgrade

Integrated Circuits/Link Settings
Issue 2 Board
Issue 3 Board
7.1 IC14 (LM1889) P
Pin No. Signal
1 (Chroma lead) Sinewave 500mV, 0.2us, DC 9.5V
2 (R-Y Input)
3 (Chroma Bias) 4.8V DC
4 (B-Y Input)
5 (Ground) 0V
12 (Video input) DC 12V unregulated
13 (Chroma subcarrier)
14 (RF Supply)
15 (Sound tank) 'Linked' 12V DC
16 (Chroma supply)
17 (Chroma oscillator output) Square wave 0.2us 4V p-p 0.8V DC
18 (Chroma lag) Sine wave 500mV p-p 2us 9.5V DC
6,7,8,9,10,11 Not connected
36
Sinclair ZX Spectrum Service Manual
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