Panasonic KX-MB263RU / KX-MB263UA (serv.man7) Service Manual ▷ View online
121
KX-MB263RU-B/KX-MB263UA-B
USB (Universal Serial Bus) block
Description
This is a USB block for data communication with PC.
Two signal lines (D+/D-) are differential signals which work in reverse phase.
This is a USB block for data communication with PC.
Two signal lines (D+/D-) are differential signals which work in reverse phase.
VBUS: CN300 1pin
D+: CN300 3pin
D-: CN300 2pin
GND: CN300 4pin
D+: CN300 3pin
D-: CN300 2pin
GND: CN300 4pin
Circuit Diagram
Sequence of normal operation
When USB cable from PC is connected to CN300, VBUS voltage goes up to 5V, and IC300 recognize the connection with PC.
Then D+ becomes about 3V : waveform (1)-1
The D+ becomes 0V, then communication between IC300 and PC is started : waveform (2)-1
When a few seconds elapsed after USB cable was inserted into CN300 ,the unit enters stand-by mode.
When PC is at Hi-Speed , waveforms are (1)-1 ~ (1)-4.
When PC is at Full Speed ,waveforms are (2)-1 ~ (2)-4.
When USB cable from PC is connected to CN300, VBUS voltage goes up to 5V, and IC300 recognize the connection with PC.
Then D+ becomes about 3V : waveform (1)-1
The D+ becomes 0V, then communication between IC300 and PC is started : waveform (2)-1
When a few seconds elapsed after USB cable was inserted into CN300 ,the unit enters stand-by mode.
When PC is at Hi-Speed , waveforms are (1)-1 ~ (1)-4.
When PC is at Full Speed ,waveforms are (2)-1 ~ (2)-4.
122
KX-MB263RU-B/KX-MB263UA-B
Waveform of normal operation
123
KX-MB263RU-B/KX-MB263UA-B
11.2.19. MAIN BOARD SECTION
3.3V TROUBLESHOOTING GUIDE
124
KX-MB263RU-B/KX-MB263UA-B
11.2.20. POWER SUPPLY BOARD SECTION
11.2.20.1. KEY COMPONENTS FOR TROUBLESHOOTING
Check the following parts first: F1, F2, D10-D13, C5, Q1 and PC1.
This comes from our experience with experimental test. For example: power supply and lightning surge voltage test, with standing
voltage test, intentional short circuit test, etc.
Caution:
This comes from our experience with experimental test. For example: power supply and lightning surge voltage test, with standing
voltage test, intentional short circuit test, etc.
Caution:
If you find a melted fuse in the unit, do not turn on the power until you located and repair the faulty parts (except for the fuse);
otherwise the fuse will melt again and you cannot pinpoint the faulty point.
otherwise the fuse will melt again and you cannot pinpoint the faulty point.
In most cases, the symptom is that nothing is output. It is more likely that the fault is in the primary side rather than the secondary
side. Check the primary side first.
side. Check the primary side first.
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