D7000 crashing / freezing / hanging fix

[Jammygit]

Hello,
A lot of people have problems with the D7000 hanging / crashing / freezing.

Well after I opened up the router I immediately discovered the problem. Whoever designed this thing thought it would be clever to only solder the CPU heat sink on 2 of the 4 corners. The other 2 corners just sit there.

So, on some routers, the heat sink will not be in full contact with the CPU and at times, it will overheat and cause the router to freeze, requiring a reboot.

The solution is: de-solder the heat sink on both sides of the circuit board, apply CPU heat transfer compound to the CPU and press the heat sink back on tight and solder back in place. On the opposite circuit board side, apply a thin layer of heat transfer compound to the existing pad and solder the heat sink back on, pressing firmly to ensure full contact.

As you can see by the mark on the heat sink, only half of the pad was actually in contact with the CPU.

This is now fixed and I've had no more issues.

I don't know if the shops still sell these, I only bought mine a year ago. But this is 100% a design fault.

[Jammygit]

As you can see in this picture, only about 1/3 of the CPU was actually in contact with the heat sink.

[tominwi]

Did you take any more/other pics of the D7000 innards? I would like a bit better perspective on the device internals, since it would mean taking-down our internet for some time to perform the mod(s).

[antinode]

> Model: D7000|Nighthawk AC1900 VDSL/ADSL Modem Router

   Is that accurate?  Look at the product label.  Firmware version?

> [...] after I opened up the router [...]

   _What_, exactly, did you open?  I see nothing like your pictures
inside my D7000[v1].

> [...] I immediately discovered the problem. [...]

   You may have discovered _a_ problem.  You may have discovered _your_
problem.  It's not immediately clear that you have discovered _the_
problem in a D7000[v1].

   I find it difficult to believe that a thermal problem would require
many weeks (rather than hours) to reveal itself.  Especially when
there's no evidence of excessive heating anywhere (on my units).

   In my D7000[v1], what I assume is the CPU heat sink is a multiply
bent piece of (originally) flat, bare aluminum, which is held against
the CPU package by a triad of springs on plastic pegs, and which seems
to make good contact with the IC package.  Not black, not soldered.

   I've never seen one, so I know nothing, but I could easily imagine
that a D7000v2, presumably a cost-reduced version of the original
D7000[v1], would have a cheaper CPU heat sink, like the one pictured
above.

   For the adventurous owner of a D7000[v1], remove the five
tamper-resistant T-10 screws (four centered under the rubber feet, one
centered under the front edge).  Pry off the (flat) top cover.  I found
it easier to start at the front edge, and press in on the lower pieces
with the vent holes, hinging at the rear edge.

   The picture attached here shows the bottom of my circuit board.
(Note the "red Internet port" peeking out from the top at the rear edge,
confirming that this is a D7000[v1].)  The prominent shiny thing is what
I believe to be the CPU heat sink.

[antinode]

    A second attached picture shows a side view of the heat sink.

[Jammygit]

This is the V2. Circled in red the CPU heat sink.

[antinode]

> This is the V2. [...]

   When offering advice on hardware, it can be helpful to identify the
hardware accurately.   (Ideally, before attaching a misleading Subject
line.)