TYPICAL PROBLEMS OF RADIO TELEPHONES "PANASONIC"

1). PANASONIC TX-9280.

Malfunction: a weak indicator light, a message about a bad battery although it is fully charged. Defect in the diode D1 according to the scheme. How to find: check the anode supply voltage is 5.5 volts, at the cathode voltage should be 5.2 volts. If the voltage on the cathode is less than 4 volts, then the diode must be replaced.

Webmaster [email protected]

2). "PANASONIC" model 3611, 3621.

There is such a defect: There is no connection of the tube to the base - the reason for this is poorly soldered output of the transmitter's quartz in the tube.

PRIORITET [email protected]

3). In the phone-answering machine "PANASONIC" model 4311.

During normal operation of the tube and the base, there is a malfunction in the operation of the AO - the cause of increased pulsations of the BP.

PRIORITET [email protected]

4). Panasonic 9080 and the like.

During operation, a crash is heard that disappears (for a time) after impact or disassembly. Reason: poor contact in the connector between the RF unit and the board.
Repair: 1). Each pin of the connector gently rotate by 90 degrees.
2). We remove the connector and seal it in place of its piece of tinned wire

Rakitin Alex [email protected]

5). Panasonic KX-TC904-B / W.

To change the TONE PULSE mode, you need to press the following key combination.
1 PROGRAM
2 AUTO
3 Press # 2 to select the PULSE mode.
To select TONE mode, press * 2 again.
4 PROGRAM

Webmaster [email protected]

6). KX-TC408 and the like.

The tube does not work, while there is a polling of the keyboard - the zener diode D17 flew out at the power supply;

KX-TS900 and similar: became a small radius of action - the filter "flows" on 903 MHz in the tube;

KX-T9500: unstable communication tube-base, and the base-tube is excellent - shameless noise detector in the pipe. Treatment - the replacement of the filter at 455KHz; / p>

KX-T7980, 9050, 9080, 9280: there is no base-pipe connection due to the departure of the transmitter or receiver frequencies (the defect is frequent for 3-4 year olds) - trimmed capacitors in the RF block were oxidized;

KX-TC408 and the like: it's impossible to adjust the frequency of the transmitter - you need a replacement varicap.

Dmitry Tsygankov [email protected]

7). Panasonic KX-T9080, 9050.

Check the work of base and tube transmitters in the following way: we make the equivalent of the load: Remove the 1.5v backlight from the unnecessary wristwatch, solder to it a small section of the coaxial cable 50 ohms and connect it to the RF block output instead of the antenna. With a good transmitter, the light should glow brightly 30mW.

Igor [email protected]

8). Defect in the Panasonic KX-T9050, KX-T9080.

Missing or unstable connection of the base with the tube. I recommend setting up RF blocks, doing this as follows:

Tube: Solder jumper to enter the test mode, press the Pause button (in the dynamics of the noise is heard). By rotating the tuning capacitors TX and RX, set the voltage to 1.8v at the VXO control points for TX and RX, respectively. For this operation, it is desirable to have a repair cable, but you can do without it and soldered to the control points with a short length of wire (the counter points are on the underside of the RF block). Voltage is conveniently controlled by an oscilloscope 0.5v / div. The setting is pretty "sharp," you need to rotate the tuners with a dielectric screwdriver. I use screwdrivers made of a strip of fiberglass with a remote foil and sharpened accordingly. And it is useful to adjust the reference oscillator to 12.800 MHz. We connect the base to the phone. Line, establish a connection, the oscilloscope looks at the signal at the output of the discriminator tube - 400Hz. - the tone of the line. Rotating the trimmer, we achieve maximum undistorted signal amplitude. By adjusting the contour of the discriminator we achieve the same. Base: Configurable similarly. To enter the test mode, the three short circuits are short-circuited. Point, then power is supplied. Before adjusting, tighten all screws firmly in the RF units.

Igor [email protected]

9). Panasonic KX-T9080.

Malfunction: very quiet caller's audibility in the handset. Communication between the handset and the base is established normally and the signal from the microphone of the handset, in the intercom mode, is heard on the base normally. Determine, in this case, where the fault in the handset and the base is very simple. Let's say you have a tube and a base connected (in the same mode of the intercom), at this moment it is necessary to de-energize the base (remove the power supply from the power outlet) and if you hear a loud noise in the tube, the fault should be searched in the database. In addition, indirectly, the serviceability of the handset is indicated by loud clicks from its speaker when you dial the number. At me the fault reason there was a bad metallization of a transition aperture in basis, between components R27, C11 (15th output IC4). Slightly pressing the screwdriver on the board it was possible to localize the malfunction.

Sudakov Alexander [email protected] >

10). Panasonic KX-T9080.

Malfunction: there is no communication between the handset and the base. As I was told - to the tube instead of 4.5V connected 12V !!! But the handset turns on and looks for the base. As a result, only transistor assemblies Q14 and Q15, and diode D13 (ie no power to the RF unit) were faulty.

Sudakov Alexander [email protected]

eleven). All radiophones like Panasonic KX-T7980 .... 9080.

Malfunction: during a conversation and at the same time your movement in the tube, you hear unpleasant rustles. Defective antenna was (less it was necessary to pick in the ear). The "spring" of the antenna is inserted into the brass adapter, on the other hand, a plate with an aperture is inserted into the adapter. It is necessary to stir the antenna and if there are rustling in the tube, you just need to compress this adapter, but not much, or it may burst. If it still burst (or compression does not help), then it should be just as it should be propaet.

Sudakov Alexander [email protected]

12). Panasonic KX-T7980.

Malfunction: the handset does not turn off when the conversation ends and the hinged cover is closed. It turned out that the axle pressing on the beak of switch S2 was broken (or worn off with time). In the magazine Repair & Service 1998 No. 2 page 34, several lines were devoted to this malfunction. I took advantage of this advice and want to tell you what I have, in this regard, there were problems. The meaning of troubleshooting is the following: put a magnet in the hinged cover, and in the tube opposite this reed magnet - with normally closed contacts (switch S2 - evaporate). Firstly, I did not find a miniature reed switch (10 mm long, 1.5 mm in diameter) with such a group of contacts. In Mitino, I was told that such things exist in nature, but they are very expensive and you will not find them here. I had to put the reed switch of medium size (about 18 mm long, 3 mm in diameter), and besides the three pin (because I did not find the medium with two normally closed contacts). Because of the large reed switch, I had to look for a powerful magnet in the hinged cover. I cut it out of a black magnet from three wadded speakers (3 GDH-xx), it turned out to be quite large 15x15x5 mm (I do not recommend smaller dimensions, because before that I ground a magnet 15x10x5 mm and with it the reed switch did not work). Now we need to choose the mutual position of the magnet and the reed switch, so that when the lid is closed, the reed switch opens. I put the reed close to the radio frequency unit (RFB), it worked at a distance of about 1.5-2 mm before the latch snapped and released, when the lid was opened for a distance of about 5 mm. The distance from the reed switch to the magnet was about 8-9mm, taking into account the PCB and the plastic parts of the cover and tube. The cover turned out to be quite heavy, so when I opened it, I recommended to hold it by hand. By the way, who knows where miniature reed switches are sold (length 10mm, diameter 1.5mm) with normally closed contacts? A miniature reed switch could be placed under a printed circuit board (near the LEDs), not above it, as I did, and accordingly it would be easier to find a smaller magnet.

Sudakov Alexander [email protected]

13). Panasonic KX-T9000, KX-T9080.

The tube does not work or fools, there is no connection with the base. Check the power to the circuit after the three-pin IC6 chip, if less than the norm-replace it.

Tomas [email protected]

14). All models of radiophones "Panasonic" type 408.

The handset's connection to the base disappears due to the following reasons:
1. The large pulsation of BP. And because of this the handset does not exchange a PIN with the base. The fault is eliminated by replacing the capacitor 470 MkF by 1000 MkF and more in the BP.
2. Zener diode failure in the charging circuit of the tube, the batteries are charged to an overcharge and the handset with the base does not exchange a security code (PIN).
3. Do not exchange PIN-code due to dirty contacts on the base charger or due to mechanical damage to these contacts.
4. The filters in the radio channels of the base and the tube were upset. Many methods of tuning were described, if normal frequency analyzers are not at hand. I suggest one more, for those models that have a Speaker button on the base. If you put the handset on the base, press this button on the base, and then lift the handset, then the algorithm of connecting the handset with the base will be executed. But with the radio channels upset, speech signals can not be heard. It remains in this position to adjust the filters and achieve the passage of both speech and telephone line signals.

Sergey Savoschenko [email protected]

15). PANASONIC KX-TC1000.

The handset-base is disconnected. Defect in the contact group of the charge on the base, - (contacts are connected to the tube via a switch on springs ?!). During operation, the connection fails and, of course, the PIN code. And immediately it's hard to understand!

Vladimir Glukhov
[email protected]
[email protected]

16). KX-TC185-B.

The radius of action of 1,5-2 meters has strongly decreased. In the tube, when establishing a connection, even a small distance, a faint noise is heard. Calculated that the fault in the tube (in the radio path). Usually, the URF is to blame for the decrease in sensitivity (it strikes out the transistor in the field (in Panas most often) or bipolar (it's the one that stands here), the transistor did not change the result.Furthermore, only m / s TB31224F- 1st mixer, 1st local oscillator , 2nd mixer, etc. to the demodulated signal, because it was problematic to replace it, I tried to replace the filter by 455 kHz, the problem was in it.

Alexandr [email protected]

17). Panasonic KX-T408.

During the repair, I encountered a malfunction of the handset, the processor does not start and does not respond to button presses. It turned out that the diode D15 is sewn from the battery to the charge stamp. As a result, Q15 opens and the handset thinks it is on the base. The leak does not leak with the tester. Thus, I restored 3 vehicles.

Konstantin [email protected]

18). Panasonic KX-T9350.

The range falls, then first of all it is necessary to check the band-pass filter in the tube (designation FL405). Almost 100% he is dead.

Alexander Miroshnichenko [email protected]

19). Panasonic KX-T9050B, KX-T9080BX, KX-T9000, KX-T9100, KX-T9200, KX-T9150, KX-T9250.

Symptom: Noise during conversation. Cause: When the battery is low, the voltage changes, which causes noise in the handset. Remedy. Change the resistance value R87 6,8kOm to 12kOm.
Panasonic technical support.

Bonus is still a few interesting solutions for various defects of Panasonic phones.

20). After the breakdown of the shutdown mechanism (handsets of the Panasonic 7980 phone and the like).

Structurally combined with the axis of the hinged cover, I analyzed the circuit diagram of the tube, used to control the tube ordinary reed switch with normally open contacts. The reed switch I placed in the area of ​​the light-emitting diodes of the tube under the board, fixing it on the light guide so that its axis was located along the tube. In this position, the reed switch is most sensitive to the magnet, which is located at the end of the hinged cover. I applied a magnetics rectangular from a magnetic furniture latch, it was not required to modify it. The main switch is short-circuited with a solder drop. One end of the reed switch is connected to the common wire (-), the second one to the processor's 60th leg (solder better to R105, which can be found on the left edge of the board: one of the contacts of the standard switch is connected to two resistors, one (R49) Another (the desired R105) to D18 and the 60th leg of the processor). When the cover of the tube is closed, the reed switch provides a low level on the 60th leg of the processor corresponding to the CLOSE mode.

Igor [email protected]

21). Radiotelephone PANASONIC KX-T408 and the like.

In several devices of this type, a defect was detected whose external manifestation was as follows: with a working battery, the handset did not react at all to the pressing of the keyboard buttons. When testing with an oscilloscope, it was found that the 32, 768 kHz clock works, and at the inputs 5-7 of the microcontroller there are high voltage levels instead of low ones. The reason is a break in the printed conductor connecting IC3 pin 3 to the microcontroller pin 33. We measure the voltages at these terminals, which should be the same and have a level of about 3.5V. If the voltage level is low at pin 33 of the microcontroller, connect the indicated terminals with a jumper from the MGTF wire.

Victor [email protected]