16 Channel (Chinese) DVR Does Not Start up - Page 1
Forum section: electronics / repair

author: kolbep
author_rank: Frequent Contributor
timestamp: January 22, 2016, 06:21:16 am
content: Ok,So here is a chinese CCTV DVR that I supplied and installed for a customer.It lasted until a few months out of warranty, now it is dead.You switch it on, the harddrive spins up, but that is it, nothing on the screen, and no beeps to say that it is booting.I have checked the Voltages coming to and from the regulators, and they are all good.Can it be bad caps (even though none of them are bulging), or would bad caps cause the supply rails to be out of spec.It is to keep an eye on a bunch of child minders.There isn't money at the moment to buy a new one, so hopefully it can be fixed.Any Ideas.Thanks

author: poot36
author_rank: Frequent Contributor
timestamp: January 22, 2016, 06:49:42 am
content: Check all the voltage rails for ripple by using the AC volts setting on your meter. Any higher then a 200mV reading means the caps are bad. If you get a reading that is higher then 3V the meter cannot be used for this test. Just hope that the hdd has not corrupted and caused the system to become un-bootable.

author: mij59
author_rank: Frequent Contributor
timestamp: January 22, 2016, 07:09:42 am
content: Yesterday one of the hard disk on my DVR failed, the hard disk made a rattling noise, after removing both hard disks the DVR started up with an error message no disk installed.You could check the backup battery.

author: Rasz
author_rank: Super Contributor
timestamp: January 23, 2016, 02:36:40 am
content: those DVRs almost always have serial console pinout - find it with a scope, connect serial cable (with proper voltage, most likely TTL 3.3v or 5v) and look at error messages

author: Muttley Snickers
author_rank: Unknown
timestamp: January 23, 2016, 02:47:34 am
content: One of the biggest problems that I have seen with these cheap arse DVRs is the lack of cooling fans, on many occasions I have opened up units that distributors have given us for evaluation only to find no fans were fitted yet on many units the connector has been included on the PCB.These units are generally installed into an enclosure or hidden cupboard with little or no ventilation and can get as hot as hell without airflow, they mostly last until a day after the warranty expires, this scenario seems to be commonplace with these DVR's.In your particular case I think you have been lucky in that the unit failed completely and at least you know where you stand, I have a stack of 16 channel Dedicated Micros, LG and other DVRs that have a habit of recording anywhere from a day to a month and then stop for no apparent reason, an intermittent nightmare to ascertain the exact problems because we just have to test them almost individually over a long period of time, these generally do not go back into service because they simply cannot be trusted.Hard disks get a hard time in DVR's, power supplies to a lesser extent and occasionally a full system reset and/or reflash of the firmware to erase the video image files can bring them back to life, backup batteries as previously mentioned can on some units be absolutely critical, a good example is the Bosch Divar 2 series which will lose it's entire programming configuration if the snaphat battery is low and the unit is restarted, the only sign of this occurring is that the units will reboot into the quick configuration menu with the real time clock reset after every restart , I verified this problem on a number of DVRs and notified Bosch about the issue and it was the first that they had heard of it happening.