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15

Amplifiers & Preamplifiers

TROUBLE SHOOTING

If you encounter a problem, please review the items below.   Be sure, in addition, to check other system
components, such as preamplifiers, CD players, speakers, speaker wiring, etc., that may be at fault.

1. Front Panel LEDs do not light – no sound.

• Check line cord for good contact in a live AC outlet.

• If the REMOTE MASTER ON/OFF CONTROL terminals (item #12, 

Fig. 3

) are used, be sure applied

voltage is b5 V and +30 VDC with proper polarity.  Refer to 

Fig. 9

.

2. Low level or no sound when operated without IR control.

• Level was previously set by IR to a low level or muted.  Simply press LEVEL (System) RESET button

as instructed in item 9, 

Fig.3

3. Sound cuts in and out every 3 to 5 seconds.

• Speaker load impedance is less than 4-Ohms for Stereo mode or less than 8-Ohms for Bridged mode.

Make changes in matching auto-formers and/or speakers as necessary to obtain higher impedance.

4. PA1235 does not turn OFF when REMOTE input voltage goes to 0 Volts.

• Be sure that the POWER switch (item 3, 

Fig. 2

) is set to the MANUAL OFF (Out) position.

5. PA1235 becomes very warm, shuts OFF, but does not come back ON automatically.

• Set POWER switch (item 3, 

Fig. 2

) to MANUAL OFF (OUT) position for 15 seconds, then back ON.

If the REMOTE MASTER ON/OFF CONTROL terminals are used, unplug for 15 seconds, then re-
plug.

6. Unit responds intermittently or not at all to IR commands.

• Look for IR noise at the IR receiver locations in the various rooms. Also, long lengths of shielded wire

from keypads or IR receivers can cause poor IR executions.  Refer to the troubleshooting sections of
the IR receiver and keypad manuals you are using.

7. The PA1235 blew its fuse (item #10, Fig. 3) as power was turned OFF using an adapter driving

the REMOTE MASTER ON/OFF CONTROL terminals.

• The supplied 220 Ohm resistor may not have been connected in shunt with the REMOTE MASTER

ON/OFF CONTROL terminals.  Be sure the resistor is connected and that the leads are making secure
contact within the screw terminals of the connector.  Refer to CAUTION notes, 

Fig. 9

.

PA1235

Summary of Contents for PA1235

Page 1: ...arge single multiple filtered power supply delivers high quality at a reasonable price IR Controlled Volume Level Volume can be ramped from zero output to maximum for individual channel pairs or as gr...

Page 2: ...12 Volt common CO Control Output on the Xantech ZPR68 to power one or more PA1235 s ON and OFF automatically with first zone ON and last zone OFF commands Default settings As received from the factor...

Page 3: ...range within 5 dB of MAX V the LED color changes from Green to Red NOTE Red indicates that volume is approaching maximum not an indication of power output level 5 Line Inputs These RCA type jacks are...

Page 4: ...VDC output 9V 70 mA with ON condition 0 Volts output OFF Standby GROUND Ground for IR IN STATUS out CI in CI Control Input Use for control of Standby ON OFF of amplifier pairs if desired instead of b...

Page 5: ...l amplifier pairs item 11 except they apply to all amplifier pairs in common That is IR commands for Volume Mute etc control all amplifier pairs together NOTE Individual control of amplifier pairs is...

Page 6: ...en the CI terminal is driven high with an external control voltage Refer also to items 9 and 11 Fig 3 4 C BAL Command Instantly returns the balance to the Center position equal volume in each channel...

Page 7: ...s in the PA1235 are set to code group number A0 Be sure to set the RC68 to the same number It may be necessary to change the PA1235 amplifier pairs to different code groups if you wish to address each...

Page 8: ...nd screws supplied NOTE You should consider some sort of rear support for rack mounted units when used in mobile applications or when located in seismically active areas CONNECTING THE PA1235 When mak...

Page 9: ...For such applications use the STEREO mode Use the BRIDGED mode for single speaker higher power applications such as in surround sound systems Use speakers with an impedance rating of 8 Ohms minimum T...

Page 10: ...control to the RS41AV and the Source Components and to power the keypads and IR receivers three leads are connected between the CB18 and a 789 44 Connecting Block 6 Since a common IR bus is used to k...

Page 11: ...R CA AC 120V 60 HZ 4 AMP LEVEL RESET RIGHT 0 9 8 6 7 4 5 2 3 1 GND 12V CB18 Parallel Connecting Block 780 80 J Box IR Receiver ROOM 2 R L ST G V IR ROOM 1 R L Smart Pad 3 ST G V IR IR CONFIRM V V POWE...

Page 12: ...ion in each room It also carries a COMMON IR signal to a 789 44 Connecting Block for control of the RS41AV Remote Switcher and the Source Components 2 Note that the ZONE numbers on the 796 20 do not a...

Page 13: ...EKEEP IR The PA1235 has been designed specifically to work well with both Zone and All Zone ON OFF management as rendered by the ZPR68 10 In this example the STATUS GND output 0 to 12 VDC of each zone...

Page 14: ...IN G 12 IN G 12 IN G ZONE 6 ZONE 5 ZONE 4 ZONE IR INPUTS 12 IN G 12 IN G 12 IN G A B A B A B ZONE 4 ZONE 5 ZONE 6 12 OUT G SYLMAR CA MADE IN U S A ZONE EMITTERS ZONE EMITTERS 796 20 SIX ZONE CONNECTI...

Page 15: ...does not turn OFF when REMOTE input voltage goes to 0 Volts Be sure that the POWER switch item 3 Fig 2 is set to the MANUAL OFF Out position 5 PA1235 becomes very warm shuts OFF but does not come bac...

Page 16: ...z to 55 kHz Input Sensitivity Rated Power stereo mode Input Gain IR Controlled Setting Max 0 5 V Default 1 0 V Min Off Input Impedance LOCAL Inputs 22 kOhms COMMON AUDIO BUS Inputs 70 kOhms Power Sour...

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