Using the Troubleshoot Charts
When using the Troubleshooting Charts, determine the symptom by screen observation and
control action. Check the Symptom Index and find the symptom that most closely describes the
problem. The page indicating that kind of problem has the Troubleshoot Chart dealing with it.
the Troubleshoot Charts list adjustments, panels and modules to be checked. If a check results
in a symptom change, locate the new symptom in the Index and follow the chart directions.
Two Ground System
The two ground system used on the Power Supply Panel and Deflection Panel are "AC" or
"Hot" ground and "Signal" or "Cold" ground. Test points TP3 and TP9 are measuring equip-
ment grounds used when checking ac line connected circuits. "Signal" or "Cold" ground test
points TP1 and all shielding on the signal plugs to panels and modules are used for test equip-
ment grounds when measuring circuits connected to "Signal" ground.
Isolation between "Hot" ground and "Cold" ground is developed by Power Transformer T l , HV
Transformer T4, and Optic Coupler IC1 on the Power Supply Panel. Horizontal Drive Trans-
former T l and Horizontal Output Transformer T2 provide the isolation on the Deflection Panel.
Isolation Protection
It is imperative an Isolation Transformer be used on the two-ground system to protect the test
and measuring instruments as well as the set electronics from mis-polarized ac line cord plugs.
TV System Overview
When the Power plug is connected to the ac line, Stand-by voltage is fed to the TS10P Con-
troller, Figure 1, and regulated to 5Vdc to keep the Microcomputer alive. A Power-On key
press at the Remote Transmitter or on-set Keyboard tunes the set to Channel 3, selects the
Antenna RF Input, and places the audio system in the Monaural mode. The TS10P Controller
displays on-screen graphics to identify the mode. The Microcomputer accepts all data from the
keyboard. If the channel data is incorrect, the TS10P display blinks six times and on the seventh
blink reverts to the previous channel number. Incomplete channel numbers revert to the previous
channel if the second digit is not entered within eight seconds. Zero cancellation is used on all
numbers below 10. Volume is controlled in 64 steps. Sound is muted until the channel is tuned
and when the Mute key is pressed on the Remote Transmitter. Press the Remote Transmitter
Mute button or Volume Up button to un-mute.
Figure 2 shows the Panel and module functions, interconnect cables, plugs, and jacks. The
heavier lines identify the signal flow from the RF Switcher to the Stereo Speaker terrninals and
the Red, Green and Blue CRTs. Switching signals, control voltages, and other operational volt-
ages are shown with lighter lines.
Adjusting a new CRT
After installing a new CRT, check the position of the new CRT raster against the Crosshair
pattern of the other two CRTs using the following procedure.
1. Place the alike magnetic ring tabs together.
2. Rotate the yoke to position the crosshair patterns together. If the patterns do not
match, adjust the magnetic ring tabs to position the crosshair points together.
3. Use a Crosshatch pattern generator to check the overall convergence, and touch
up convergence if necessary.
