Panasonic KX-NT305X Service Manual ▷ View online
5
KX-NT305X / KX-NT305X-B
4.2.
Circuit Operations
4.2.1.
LED Circuit and KEY Input Circuit
Circuit Operation:
A drive pulse wave, as in Fig.1, is output by IC1. That signal goes through the drive digital transistor and connects the key button
and LED cathode. By pressing the key, the drive pulse wave is input to Pin20-Pin24 and Pin28-Pin32.
In order to light the appropriate LED, the LED control port is turned ON. That result LED is lit by the pulse Driver.
A drive pulse wave, as in Fig.1, is output by IC1. That signal goes through the drive digital transistor and connects the key button
and LED cathode. By pressing the key, the drive pulse wave is input to Pin20-Pin24 and Pin28-Pin32.
In order to light the appropriate LED, the LED control port is turned ON. That result LED is lit by the pulse Driver.
6
KX-NT305X / KX-NT305X-B
5 Installation Instructions
5.1.
Disassembly Instructions
1. Remove 3 Screws A.
2. Remove the Cabinet Cover.
2. Remove the Cabinet Cover.
3. Remove the Main Board from the Cabinet Body.
7
KX-NT305X / KX-NT305X-B
For KX-NT343/KX-NT346
The KX-NT303/KX-NT305 allow 12/60
additional CO buttons to be connected to this unit. These
buttons are used to seize an outside line, make a call using
One-touch Dialing, or perform a feature that has been
assigned to the key.
additional CO buttons to be connected to this unit. These
buttons are used to seize an outside line, make a call using
One-touch Dialing, or perform a feature that has been
assigned to the key.
To prevent damage to the telephone, be sure to unplug
the extension line before you install or uninstall the
Add-on Key Module.
the extension line before you install or uninstall the
Add-on Key Module.
<with a KX-NT346>
1
Open the cover.
2
Attach the KX-NT305 to your unit with the screws
(include).
(include).
3
Plug the flat cable into the connector (1), then bend
the cable slightly as shown (2).
the cable slightly as shown (2).
4
Close the cover.
8
KX-NT305X / KX-NT305X-B
6 Troubleshooting Guide
6.1.
No Operation
CROSS REFERENCE:
Waveform (P.15)
6.2.
LED Does not Light
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