T R O U B L E S
(2) One of amplifier tubes may be burnt out. If so, replace with a new tube of same type.
(3) One horn may have short in line or winding through which sound current passes, thereby causing others to receive no power. Turn off all horns by means of keys on output control panel, or if these are not provided, then by means of switches in horn cutout box back-stage, and then try to locate bad receiver by turning horns on and off one at a time. They should all give volume except bad one. If defective receiver is found, replace by spare as described under "Replacements".
(4) Possibly fuses in horn supply circuit on battery panel have blown.
(5) Check reproducers by switching from one to the other on fader. If one is bad, replace as described under "Replacements". If neither gives any sound, check fader and circuit by means of headset, or as follows.
(6) In systems using 41, 42 and 43 type amplifiers, left-hand key at top of fader, called fader cut-out key (Fig. 7), can be used to cut out either side of fader circuit. If this key is thrown to left, (red) for example, reproducing equipment on "red" machine will be connected direct to amplifiers without going through "red" side of fader. Similarly when key is thrown to right (white) side, "white" machine is connected direct to amplifiers. To check whether trouble is due to defect in fader, try using cut-out key in this manner. If this eliminates trouble, use cut-out key for changeovers, instead of fader, until our service engineer can repair or replace latter. Regulate volume by means of gain control on 41-A amplifier.
(7) With film reproduction, exciting lamp may be out of focus or burnt out, or opening in photoelectric cell may be out of line with opening leading to film compartment. Position cell properly.
(8) If system uses one or more 43 type amplifiers, and plate current reading on one of these amplifiers is very low or is zero, probably a condenser has failed. A further indication of this is that plates of rectifier tubes of amplifier affected may begin to get red hot. Turn off power on this amplifier, by means of amplifier starting switch. Locate defective condenser as follows:
Remove front cover of amplifier. The condensers are connected in parallel in two groups, the first group containing C-2 to C-10 inclusive and the second group C-11 to C-19 inclusive. Unsolder connection coming from behind panel to lower terminal of 0-2. Turn amplifier starting switch to "Plate". If plate meter reading is now normal, it shows bad condenser is in C-2 to C-10 group. Shut off switch. Restore connection on C-2, and unsolder connection between C-2 and C-3. Turn on switch. If meter reading still normal, it shows C-2 is good and bad condenser is in C-3 to C-10 group. Restore connection on C-3 and unsolder connection between C-3 and C-4; test again with switch and meter, and so on until a condenser is found which when connected causes meter reading to fall. This will be the bad condenser. Cut it out by connecting together directly the lower terminals of the two adjoining condensers, instead of making the connection through the lower terminal of the defective condenser.
If in the first place, when the connection coming from behind the panel is unsoldered from the lower terminal of C-2, this does not bring the meter reading back to normal, it shows that the defective condenser is in the C-11 to C-19 group. Then restore connection on C-2, unsolder connection between C-11 and C-12, and test for defective condenser as already described for C-2 to C-10 group.
(9) If all fuses are in good condition and all current and voltage readings normal, probably there is a ground, open circuit or short circuit somewhere in the system. Try to locate fault with headset, as described under "TroublesGeneral". Possibly a loose or grounded connection may be found, which can easily be repaired.
If system has no emergency amplifiers and includes one 43-A amplifier, and this is found to be defective, disconnect its "Input" mid "Output" terminals (accessible by removing the back cover) and run system off 500 ohm "Output" terminals of 42-A amplifier. If system uses two 43-A amplifiers and one is found to be defective disconnect its "Input" and "Output" terminals. When cutting out an amplifier as just described the loss of power can be partly compensated for by running the fader higher, or raising the gain control dial on the 41-A amplifier one or two steps. Be careful not to impair quality by raising fader or gain so much as to overload amplifiers.
Poor Quality or Noisy Output
(1) See paragraph #1 under previous heading "Volume Falls Off or Ceases".
(2) One of amplifier or rectifier tubes may be burnt out. Replace with spare of same type. For amplifier use, this must be a new tube.
[COVER] [REGISTRY] [TITLE PAGE] [CONTENTS] [INTRODUCTION - PAGE 1] [STORAGE BATTERIES - PAGE 9] [STARTING AND TESTING - PAGE 14] [SETTING UP - PAGE 20] [REHEARSING - PAGE 27] [TROUBLES - PAGE 29] [REPLACEMENTS - PAGE 34]