Lorex DVR: What is this?

[Ed Sowell]

My Lorex LNR 4082 stopped working. Opening the case revealed a broken heatsink fan, which I replaced. Still no joy. One thought is it's because when the fan failed the chips under the heatsink got fried. Another possibility is the power supply is flakey.

So, my first question is what are those chips, and how likely is it that they're ruined?

I'll try to upload a photo, but not sure I know how...

 

[Ed Sowell]

 

[kellys_eye]

It's not a socketed chip so would require specialist equipment to replace - if it was dud. They usually have thermal shut-down protection (not always though).

Doesn't help that we can't read the text on the top of it - focus!

 

[Ed Sowell]

Thanks. You're right. I would never attempt a repair at that level. But, I thought if someone recognized it and confirmed it would likely have died when the fan broke, I'd know for sure I had to find the board (unlikely) or pitch the whole thing. Sorry about the shaky hand on the camera. The numbers are (on 3 lines):
21-517
N1303
80146168

I'm going to post a question on the power supply, the other possible culprit, separately.

 

[kellys_eye]

Sort the PSU out first. The main chip is probably ok but needs a few fan - d'uh.....

Based on your other post (PSU) you're not getting any supply to the board.

 

[Ed Sowell]

Sort the PSU out first. The main chip is probably ok but needs a few fan - d'uh.....

Based on your other post (PSU) you're not getting any supply to the board.

There is power to the board, witnessed by heatsink fan and some flickering LEDs. The power LED on the front panel flickers, for example. However, since Black/Yellow measures 10.8v, it might not be high enough to run the CPU or whatever. Wish I know what those 2 chips under the heatsink were. perhaps a GPU? There's another fan-less, finned heatsink on the board.

BTW, I did replace the heatsink fan, and the one in the power supply. Should have taken some pics while I had it open.

If I had confidence that the board was OK I'd just get a new PS, but if the board is shot that would be $100 down the drain :-(

Thanks for your help.

 

[kellys_eye]

There isn't two chips under the heatsink. The square board IS the chip and would need to be replaced as a whole if there is any issue with it. The package (small board/IC) is known as a BGA package (ball grid array) and are notoriously difficult to replace without expensive equipment.

If the board needs 12V to run then 10.8V isn't going to cut it. You could drag an old PC power pack into service to bypass the 'missing' supply but since you are going to need the original PSU working to fix the unit you may as well start by taking that apart.

 

[Ed Sowell]

I want to report success! Here's a summary, based on what my volunteer circuit guru told me:

The original problems were identified as a visibly blown 0.56 Ohm resistor at R355. Continuing though the circuit, the MOSFET Transistor at Q351 (W9NK90Z) was bad. These tested bad from the beginning. After replacement, there was 52 volts and 12 volts on the vertical PCB, but the voltage was not being sent to the wiring harness outputs. Other transistors were removed and tested, with not much help.

Still dealing with incorrect voltage at one of the outputs, another visit to the forum led to replacing the IC(CM6800UBX) on the vertical board, sourced in China. That was the last problem! Apparently, it had gone out along with the Q351 MOSFET and the 0.56 Ohm resistor. With all PS voltages now correct, the system worked perfectly after reassembly. I was a happy camper indeed when the display lighted up with "Lorex," and images filled the screen with images, one after the other, as I cautiously plugged the cameras in one at a time.

Yet, one has to wonder how long it will last. If the original problem was failure of the processor fan, it's going to happen again since the replacement fan appears to be exactly like the OE. So, I'm now thinking about an upgrade. Haven't found it yet, but there must be a higher quality one out there somewhere. I'm thinking steel shaft, ball bearings, and quiet.

There's a photo earlier in this thread showing the OE fan on the board. Basically, it's a 45x45mm, 12v, 2-wire heatsink fan with outboard tie-down pins. I believe it was commonly used in laptops, DVRs, etc. a number of years ago. From the photo, you can see that a larger one could be fitted using the 4 other post holes, seen about a 1/4" farther out... about 50mm center-to-center. If anyone can suggest a source of a quality replacement, I'd appreciate it.

Many thanks to all in this discussion.

Ed