Orbi WiFi 7 RBE973
Reply

Re: Disassemble CM1150V

craig-wagner
Guide

Disassemble CM1150V

My CM1150V recently got knocked off my desk. There is now a rattling sound inside and it won't power on. I figured I'd take a shot at opening it up to see if I might be able to fix it myself. Does anyone know the size of the torx screws that hold on the base and that are at the top and bottom of the back panel?

Model: CM1150V|DOCSIS 3.1 Nighthawk® Multi-Gig Speed Cable Modem for XFINITY® Voice
Message 1 of 13
FURRYe38
Guru

Re: Disassemble CM1150V

You might take it to a hardware store or home depot or lowes and have someone help you fit something to those screws. I don't off hand thought i problaby have something that does fit...Smiley Embarassed

Message 2 of 13
craig-wagner
Guide

Re: Disassemble CM1150V

FWIW, it's a T8 torx. I got the three visible screws out. After that you have to kind of slide the side without the lights towards the back of the unit to unclip it and it comes apart. Looks like what broken when it fell was a plastic pin and spring that held the heat shield against the processor. I'll see if I can jury rig something to fix it and then see if it powers back on.

Message 3 of 13
antinode
Guru

Re: Disassemble CM1150V

> [...] it won't power on. [...]

 

> [...] what broken when it fell was a plastic pin and spring that held
> the heat shield against the processor. [...]

 

   I'd expect a loose heat sink to cause trouble after some time has
passed, and the (now-detached) device overheats.  I would not expect it
to cause immediate "won't power on" (which is a bit vague).

Message 4 of 13
craig-wagner
Guide

Re: Disassemble CM1150V

The heat sink has plastic pins with springs on two diagonally opposite corners. On the other two diagonally opposite corners there is a metal pin that appears to make contact with a solder point. Because of the missing spring pin one of those metal pins is not touching the circuit board. I suspect that's the reason for lack of power. I'm not sure what is vague about "won't power on." When I plug it in and turn it on the device does not indicate it is powered up (i.e. the power light does not come on).

Message 5 of 13
antinode
Guru

Re: Disassemble CM1150V

> [...] I suspect that's the reason for lack of power. [...]

 

   You can see it better than I, but I wouldn't expect a heat sink to be
used for a power connection.  You can run the experiment, but my
expectations would be low.


   This is all low-voltage stuff.  I'd try to hold loose stuff in place
by hand before putting much effort into manufacturing replacement
plastic pins.

 

> [...] I'm not sure what is vague about "won't power on." [...]

 

   To someone, that could mean that it doesn't respond as expected.
"the power light does not come on", on the other hand, describes an
actual (non-)event -- no interpretation required.

Message 6 of 13
FURRYe38
Guru

Re: Disassemble CM1150V

Check the power voltage coming out the power adatper tip as well...Volts and amps should match whats is seen on the adapters sticker specs.

 


@craig-wagner wrote:

FWIW, it's a T8 torx. I got the three visible screws out. After that you have to kind of slide the side without the lights towards the back of the unit to unclip it and it comes apart. Looks like what broken when it fell was a plastic pin and spring that held the heat shield against the processor. I'll see if I can jury rig something to fix it and then see if it powers back on.


 

Message 7 of 13
antinode
Guru

Re: Disassemble CM1150V

> [...] Volts and amps should match [...]

 

   Unless you actually know how, trying to measure the current could
cause trouble/damage.  Poking around aimlessly with a voltmeter can be
pretty harmless; not so with an ammeter.

Message 8 of 13
craig-wagner
Guide

Re: Disassemble CM1150V

For anyone who may still be following this saga, I finally got back to my attempts to revive it.

 

As many suspected, my theory that the heat sink was acting as a circuit breaker was incorrect. In the attached photos, notice the four pins outlined in red. When the heatsink broke loose it hit those pins and bent them so that the two closest to the heat sink were touching. I carefully bent them back and then wondered if that had somehow caused the device to lock up. I held down the reset button for about 15 seconds then plugged it in again and voila, the lights came on.

You can see in the cyan outline the remaining pin and where it broke. I now need to figure out how to either replace that missing pin or find another way to secure the heat sink to the chip. I'm considering removing the remaining pin and using a thermal glue or tape (e.g. https://www.amazon.com/Aikenuo-Adhesive-performance-Heatsink-Computer/dp/B075FRPXQ5) to secure the heatsink to the chip.

 

20210313_061148 (Small).jpg20210313_061340 (Small).jpg

Message 9 of 13
craig-wagner
Guide

Re: Disassemble CM1150V

20210313_061148 (Small).jpg

Message 10 of 13
antinode
Guru

Re: Disassemble CM1150V

> [...] notice the four pins [...]

 

   I can't (yet) see your pictures.  In-line images must be approved
by a moderator before others can see them.  The time required varies.
Attachments have no such limitation.  Of course, attachments have their
own one-per-message limitation.

 

   A set of four pins (0.1-inch spacing) might be the diagnostic serial
port, on which you might find a (5V?, 3.3V?) power supply and ground.
Shorting those should be enough to keep the whole power supply shut down
for self-protection.

Message 11 of 13
craig-wagner
Guide

Re: Disassemble CM1150V


@antinode wrote:

I can't (yet) see your pictures.  In-line images must be approved
by a moderator before others can see them.


Thanks. Was not aware of that and the site didn't provide any information in that regard.

Perhaps links to the images in Google Photos will work.

 

https://photos.app.goo.gl/BxCcbfUsZBYsH3dD6

 

https://photos.app.goo.gl/qAFDSa9qfznzsVYE7

Message 12 of 13
antinode
Guru

Re: Disassemble CM1150V

> Perhaps links to the images in Google Photos will work.

 

   Yup.  Looks like a serial port, which could explain the symptom.

 

   Glad to hear that you got it figured out.  Any scheme which gives a
good thermal connection between the chip and heat sink should work,
whether of not it closely resembles the original.

 

   More satisfying than buying a new gizmo.

Message 13 of 13
Top Contributors
Discussion stats
  • 12 replies
  • 1898 views
  • 3 kudos
  • 3 in conversation
Announcements

Orbi WiFi 7