1. N5 Series DVR Maintenance Work Training Program
Version 2011
kevin
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2. N5 Series Model DVRXX04LE-A DVRXX04HE-L DVRXX04LE-AS DVRXX04HE-T
DVRXX04LE-AL DVRXX04LE-U
DVRXX04LE-L
DVRXX04LE-S

3. platform N5 series(CPU:7105+encode chip hi3511/3512)
LE-AL and 0404LE-AS(avsi) (CPU:7105+encode chip:VS2801)

4. DVR0804LE-A Layout

5. DVR0804LE-A Layout MII LMI VIDEOOUT UART×3 USB×2 AUDIO SATA
RS232、RS485、FRONT PANEL
NET

6. DVR1604LE-A Layout

7. DVR0404LE-AS(obsolete version) Layout

8. DVRXX04LE-L, DVRXX04LE-S Layout

9. DVRXX04LE-U Layout 8

10. DVRXX04HE-T Layout

11. Boot up Process
●Turn on the DVR, the main board provide+5_STB,the SCM 89S52 which in the front panel becomes active to work，the PWR_S signal which controls the start of power will pull down some power to work .
●The CPU begins working after the power booted up properly. First, the COM initialized so that the boot up information can be sent to the COM to display. Second, read the software version and hardware version from the main board. The following application performance and function will respond respectively according to the version it reads when boots up.

12. Boot up Process
●The system initializes the PCI BUS, PCI controller, 3511 device, and then boots up the network service, high-speed COM, network card driver, flash device drive, USB drive, loads file system, real-time clock module, SATA module, 3511 module.
●Finally, boot up the applications and start the DVR properly.

13. Power Working Principle
To Front panel
To power chip

14. Power Working Principle

15. Power Working Principle

16. Power Working Principle

17. Power Working Layout

18. Power Working Layout
+12V
HI3511_IO
KSZ8041NL

19. Window split A/D switch chip
PCB Parts Layout
BNC
HDMI
VGA
Window split A/D switch chip
9116
Network chip
External alarm input
9115
PTZ chip
CPU
CPLD
Flash
Clock chip
DSP
Power chip MP1482
Power chip MP1482

20. Audio/Video A/D Switch
75Ω resistance
video coupling capacitance
Audio coupling
4CH audio digital signal output
A/D chip 2
A/D chip 1
2CH video digital signal output

21. Video Real-time Process
●Real-time video process：The video signal inputs from the Q9. Via the resistance 75Ω and coupling capacity (0.1uf) , it goes to the A/D switch and window split chip Here it is turned to the digital signal and sent to the 3511 to encode. The compressed signal will be sent to the 7105 to implement the OSD and D/A switch output via the PCI BUS.
Q9→Video A/D switch 2864→3511 compress encode→CPU（7105） →Video port
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22. 2864 Video Principle

23. Audio Real-time Process
●Real-time audio process ：The audio signal adopts the cascade connection mode. After the chip 2 processed the Ch5-8 audio, it is from the Aout to Alink of the chip 1. After the chip 1 processed the Ch1-4 audio, it goes together with the signal from the Alink. From the Aout to the audio amplifier chip to process.
Audio-Ch5-8 →2864(Chip 2)
Audio-Ch1-4 →2864(Chip 1) →Audio amplifier chip
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24. Audio Real-time Process
2864(Chip 2)
2864(Chip 1)
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25. Video Record and Playback Process
●Video record process：
Video A/D switch 2864→3511 compress encode→CPU（7105）→Save to the HDD
●Video playback process：
HDD→ CPU（7105）decompress，D/A switch→video amplifier chip （9115-BNC, 9116 –VGA, TPD12S521-HDMI）

26. Video Output Chip
BNC
VGA
HDMI

27. Here I will give you some main fix solution of mainboard faulty repairing , that is the way our repairing team are doing to repair the mainboard .

28. Network·Local Playback Video Problem
No bit rate：First, check the main board working voltage and clock. Make sure the power and clock are OK and the firmware version is OK. Second, check the 2864 digital output signal VI0DATA0-7 and VI1DATA0-7. if there is a problem ,you can estimate the 33orm resistance or the 2864 is improper. . If VI0DATA0-7 and VI1DATA0-7 are OK, usually it is the 3511 or the 3511 memory is abnormal.

29. Network·Local Playback Video Problem
Bit stream is OK but the playback is abnormal：You can put the HDD of the record to the normal main board since we can not detect the main board signal. If the playback is OK, usually it is the decompress module (7105 or memory) is malfunction. If the playback still has problem, usually the compression module (3511 or memory) is malfunction.

30. Video Output Problem
BNC has no output：First, use the multimeter to check the resistance R263 and R265. If these two parts are OK, you can use the oscillograph to check the power + 5AU (4-pin ) of the signal amplifier chip U26（SGM9115） and video input signal CVBS (1-pin). You can compare the signal with the normal main board. If the video signal CVBS is abnormal, the problem may lies in the 7105.If the CVBS is OK, you can replace the GM9115 to check the problem.

31. Video Output Problem
VGA has no output：You can refer to the BNC (previous page ) to check since the VGA amplifier chip U27（SGM9116）is similar with the BNC amplifier chip. The previous one has three channels to amplify and the BNC has one channel to amplify.

32. Video Output Problem
HDMI has no output：Usually it is the poor welding of the HDMI and 7105 , You need to make sure the HDMI seat is properly welding and then check the U23（PN521）power. You can replace the U23（PN521） to check the PN521 is OK or not. If it is OK, then you can estimate the 7105 is abnormal.

33. Audio Record and Playback Process
●Audio record process：
Video A/D switch 2864→3511 compress encode→CPU（7105）→Save to the HDD
●Audio playback process：
HDD→ CPU（7105）decompress→The first 2864→ NE5532 audio amplifier –BNC audio main output

34. 2864 Audio Principle
To 3511
From CPU

35. Audio Amplifier Chip

36. Audio Problem
Real-time audio problem：Please make sure the audio signal goes to the 2864（82-pin,83-pin,84-pin,85 -pin）). You can use the oscillograph to test the signal to remove the problem from the front-end input. Then you can use the oscillograph to check the clock signal of the 79-pin of the If it is abnormal, usually the problem is 2864.

37. Audio Problem
Playback audio problem：You can see the audio A/D is OK if the real-time audio is proper. You can put the record to the normal main board to playback. The audio decompress (7105) is malfunction if there is audio. The audio compress (3511) is malfunction if there is no audio.

38. RS232 COM

39. RS232 COM Information

40. RS232 COM Command setenv dh_keyboard 0---Open COM
setenv dh_keyboard 1---Close COM
setenv ID s/n Write SN
mac address Write mac
COM upgrade command：
setenv serverip
setenv ipaddr
save
run da------Upgrade armboot file
run up------Upgrade update.img file

41. RS485 PTZ Control

42. USB in the Front/Rear Panel

43. Can not detect the USB Can not detect the USB
First, use the multimeter to test the +5_USB voltage of the first-pin of the USB port. If there is no 5V, you can check the 3.3V and 5V of the U21(MIC2506). You can replace the U21(MIC2506) to check if it is OK.
If +5_USB is OK, usually the problem is from the poor soldering of the CPU（7105) since USB connects with 7105.

44. Network Chip
Or use 6.2K+287R/1%

45. Network voltage Transformer/RJ45

46. Network Problem
Common malfunction:Network chip U1（KSZ8041 is abnormal ;Network voltage transformer T1（H1102）is abnormal
First, you need to test U16（KSZ8041）power supply 3.3V and 1.8V
is OK or not. Usually the problem results from U16（KSZ8041）chip poor
welding and malfunction. You can replace the U16（KSZ8041） to check.
Second, you can check the protection canal U33(V05) has burned out or
not. You can use the multimeter to check the 1/3/4/6-pin is short circuit or
not. If the network chip and network voltage transformer both are OK, usually the problem is from the CPU（7105） poor welding or damage.

47. SATA HDD Port

48. Storage Problem Can not detect the HDD Please check：
HDD power supply is OK or not.
If the HDD port capacitance is OK, the problem may result from the CPU（7105） since the HDD is in the 7105.

49. Clock Chip

50. Time Initialization Time initialization:
U25（1338）is the clock chip. It integrates the crystal oscillator of the clock. BT1 is a battery to provide the 3V power to the U25(1338).
Please make sure the 3V power is OK. Then you can replace the U25（1338）to see the clock chip is OK or not.

51. Alarm Circuit

52. Alarm Abnormal External alarm signal process：The external alarm
signal will be input and then received by
CPLD(EPM240) after processes by two triodes.
Here we take one channel as an example
After input the alarm signal , please use the oscillograph to test the third pin of the
triode Q37. If it is high level, then it is OK. If it is low level, then you can see the
Q37 is damaged or the resistance R374 is disconnected. If the 3-pin of the Q37 is
high level, you can test the 3-pin of the Q36. If it is low level, it is OK. If it is high
level, you can see the Q36 is damaged. If above situations are all OK, you can test
the CPLD program or the CPLD chip. If the alarm light is always on, the problem
may result from the resistance R376,R375, R373 , you can use the multimeter to test them, or the two triodes are malfunction.

53. Can not boot up
Software boot up process：Please make sure the main board FLASH program and CPLD is OK. After the main board boots up, the CPU read the armboot of the Flash and running in the memory （K4T1G164QQ）， then it reads the application program from the Flash to boot up the main board.

54. Can not boot up The problem may result from：
　 1 Kernel voltage 1.2V is abnormal
2 54MHZ crystal oscillator is abnormal
3 CPU crystal oscillator is abnormal
4 Reset chip 811 is abnormal
5 CPLD is malfunction or the application error
6 Flash application loss or error
7 CPU7105 is malfunction（damaged or poor welding）
8 CPU memory is malfunction
9 Can not detect the compression chip 3511

55. Can not boot up You can follow the steps listed below：
Use oscillograph to make sure the working voltage +5V(L14), +3.3V(L13), +1.8V(L5), +1.2V(L7) are OK. And then test the crystal oscillator X3（30MHZ）、X2(54MHZ)、X1(27MHZ) is OK or not. Now you can check the 2/3/4-pin of the reset chip U7（IMP811）, make sure the voltage is 3.3V. Test the 2-pin of the power module U22 （AP ）, make sure the voltage is 2.5V. Finally you can check the CPLD is OK or not. You can burn again to make sure the CPLD application is OK or the CPLD chip is OK. Then you can burn the Flash application again.

57. Can not boot up
if flash application is OK. You can press the 7105 to see whether it is poor welding or not if other parts are all OK. And if you have tested some earth impedance which do not totally short circuit , but lower than normal data from multimeter shows, you can power on the mainboard , then touch some part of mainboard which connect with the voltage, you can feel which chip is hotter than others, then mostly , the problem is the hot chip may damage,you can replace the chip to test it .

58. Common problem for N51 series
Starting kernel ...
Uncompressing Linux done, booting the kernel.
Auto login as root ...
warning: cannot change to home directory
root login on `ttyS000'
BusyBox v1.1.2 ( : ) Built-in shell (ash)
Enter 'help' for a list of built-in commands
When you see these information in the ncom of the N51 device and at the same time , the mainboard can not start up appropriately, mostly it is the reason of /mnt/mtd/Log/Log file can not read and write, and it will make the firmware abnormal and can not run the firmware appropriately, in this case , you can erase FLASH Config zone to fix the problem, you can execute erase 0x80ce0000 0x80d7ffff in the uboot menu （please notice the command need to input correctly otherwise you may cause other problem when you erase some other part of the address ）

59. here is the detailed operation as below：

60. Thanks！