General Symptom 2: (No. Rf Output, Low Gain, Or Distorted Picture.) - Scientific Atlanta 8500 SERIES Operator's Manual

Condition
Table 5-4. Conditions and Corrective Action for
Step 5 of Paragraph 5. 4. 1 - continued
Action
Repair Problen1 .Found
5.
Voltage indica- None. Check regulator wir-
tions at pin 3 of ing. If okay, replace
either regulator control board and re-
are still low or insert P308.
not present.
5.4.2
Step 1.
Step 2.
Step 3.
33T056A
General Symptom 2: (No rf output, low gain, or distorted
picture. )
Note
Make sure rf input signal is clean with approximate
0 dB mV level when performing the following steps.
If the television picture is snowy or not present, inspect the
PROM socket for damaged or loose pins. Also try replacing
the PROM with a known working PROM.
Be sure to turn off power before ren1oving on installing
a PROM.
If the television picture is distorted and displays horizontal
hum bars across the screen, the problem is probably
ripple in the ac power link. Refer to step 4 under para-
graph 5. 4. 1.
If the problem can not be corrected by steps 1 or 2, the problem
must be isolated further. There are basically two modules that
can control picture quality, the up /down converter and/ or the
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