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RICHARDSON'S BLUEBOOK OF PROJECTION
2.
To Determine the Cause and Correction of
LOW VOLUME, FAULT LOCATION UNKNOWN
NOTE: Because of the wide variety of monitoring circuits used today, this chart does not provide for faster trouble-shooting by comparing monitor speaker output with stage speaker output. Such provisions, suited to individual projection room conditions, may profitably be added by the reader.
THE TROUBLE TESTS
THE CONDITION FOUND
NEXT TEST
'•
•
Observe volume control settings
• All control settings normal One control setting low
• No. No.
2 17
2.
Check reverse feedback settings
All settings normal One or more settings low No reverse feedback adjustments
No. No. No.
3
17 3
3.
Observe all tube filaments
All filaments normal One filament not lighted One or more filaments dim
No. No. No.
4 18 18
4.
Observe readings, all installed meters
All readings normal
One or more readings low
No. No.
5 19
5.
Observe all exciter filaments
Exciter filaments normal One or more filaments dim
No. No.
6 20
6.
Check volume of emergency
Emergency volume normal Emergency volume low No emergency channel
No.
No. No.
26
27
7
7.
Check speaker field excitation
Field excitation normal Field excitation low
No. No.
8 32
8.
Check volume of other projector
Other projector normal Other projector volume low
No. No.
35 9
9.
Using test meter, read all photo-cell and tube socket voltages
One or more voltages low All voltages normal
No. No.
37 10
10.
Check all sound circuit switches for faulty or dirty contact; check rotary controls for loose knob or shaft giving false indication
All contacts normal TROUBLE FOUND
No.
II
II.
Using headphones, check volume atall external sound connections from sound changeover to speakers, to isolate faulty unit
Amplifier found faulty Filter network found faulty Volume levels cannot be estimated Fault isolated to backstage circuits
No. No. No.
No.
13 14 12
38