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D200 Reassembly thread...
#8
    I'm sorry for not being able to post anything Friday or yesterday as promised but I hit a snag late Friday afternoon that had me putting on the brakes until I understood it better. I found 2 inductors shown in pic with the edges of their top covers lifting. On further examination I found they were almost falling off on their own as I was able to coax them off just by gently lifting with my fingertip at any/every edge... ya might say 'dangling by a thread.' Once inside I could see the what was once crystal clear adhesive used to keep those covers applied to the ceramic-ferrite (highly magnetic) boxes that house the inductor windings was compromised. That is to say the adhesive 'squares' had started to yellow, heat-harden and become brittle. This on a brand new D200 that only arrived June 1st this summer and has been out of use for more than a third of its time with me. Needing to understand this better I halted reassembly forthwith and spent yesterday researching this part which is made by "Coilcraft" and labeled H36-0325L/1434D. It must be an inductor proprietary to Devialet as nothing was publicly available but the "D" does seem to represent "digital" on other similarly numbered inductors from Coilcraft. Virtually EVERY part marked with a "C" inside the Expert series comes from Coilcraft and there are dozens!

As to this issue I'm still debating how I should proceed. I could use a 100% silicone adhesive around the tops to resecure them and have no worries about them coming loose again due to the working temp of silicone at 450*F/232.2*C. Near as I've been able to determine the adhesive Devialet/Coilcraft used is rated at 70-100*F/21-38*C. We all know that dog can't hunt for very long inside an expert! Another thing I may try is a small/thin pin heatsink on top of each inductor housing or a single rectangular one placed atop both with Arctic Alumina heatsink adhesive. Think of "AA" as a true 2-part epoxy heat-transfer fixative for heatsinks. Or some variant of the 2 options mentioned above. I'm going to take the day to to watch American football and mull it over.

You can easily see in the pic how the factory adhesive has yellowed... is drying out and becoming crispy/brittle as most adhesive quality has dried up. The 'covers' used over these inductors are nothing more than paper. An intermediate layer with the inductor model number printed on it adhered to a top layer which has been painted/coated black with perhaps some EFI/RMI or heat-resistant resistant paint. The black side is what you see on top of the inductor if you pull the belly pan. It gives the illusion of being a solid black square that is 25mm square X 8.5mm thick.

No intent on my part to cry wolf here as I have no idea what would happen, if anything, were either of these inductor covers were to separate/detach and fall off the inductors in normal use as they would simply fall down into the underside of the belly pan. Don't know if errant EFI/RFI would increase or heat would become a bigger factor. All I know is either Devialet or Coilcraft went to some trouble and expense to attempt to cover these inductors and my intent is to improve on their effort and better it if possible.

My remedy will be disclosed at some point after I've done it either by text or self evidenced by virtue of an updated picture. My reassembly has been plagued by several issues such as this and its painfully slow-going. I've determined that several places that had thermal pads before will now be better-served with convection cooling instead of conductive cooling since convection cooling is significantly more efficient than conductive and far more efficient than radiant cooling. In same places, especially where 'large' thermal pads were used there's no getting around using them again as they're simply a better option in those places. I'll catch everyone up to what I've done related to this as soon as its been carved in stone.
Statements in my posts are opinion only, not to be construed as fact. Any projects I engage in are at my own risk! Their outcome cannot be assured and may result in success, small/no change or catastrophic failure. I encourage no one rely on anything I say or do as gospel and to realize your mileage may vary!
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Messages In This Thread
D200 Reassembly thread... - by Manoet - 15-Sep-2015, 02:04
RE: D200 Reassembly thread... - by absolutk - 18-Sep-2015, 08:51
RE: D200 Reassembly thread... - by Manoet - 18-Sep-2015, 13:35
RE: D200 Reassembly thread... - by brit - 18-Sep-2015, 14:42
RE: D200 Reassembly thread... - by Manoet - 18-Sep-2015, 15:45
RE: D200 Reassembly thread... - by GuillaumeB - 18-Sep-2015, 16:01
RE: D200 Reassembly thread... - by Manoet - 18-Sep-2015, 16:37
RE: D200 Reassembly thread... - by Manoet - 20-Sep-2015, 17:13
RE: D200 Reassembly thread... - by Manoet - 21-Sep-2015, 14:29
RE: D200 Reassembly thread... - by Manoet - 22-Sep-2015, 13:45
RE: D200 Reassembly thread... - by Manoet - 22-Sep-2015, 19:33
RE: D200 Reassembly thread... - by mauidan - 22-Sep-2015, 20:55
RE: D200 Reassembly thread... - by kenreau - 22-Sep-2015, 21:57
RE: D200 Reassembly thread... - by Manoet - 22-Sep-2015, 22:24
RE: D200 Reassembly thread... - by mauidan - 23-Sep-2015, 03:12
RE: D200 Reassembly thread... - by Manoet - 23-Sep-2015, 09:07
RE: D200 Reassembly thread... - by Manoet - 25-Sep-2015, 01:26
RE: D200 Reassembly thread... - by Manoet - 26-Sep-2015, 17:21
RE: D200 Reassembly thread... - by warpeon - 26-Sep-2015, 23:06
RE: D200 Reassembly thread... - by Manoet - 27-Sep-2015, 00:30
RE: D200 Reassembly thread... - by Manoet - 27-Sep-2015, 23:59
RE: D200 Reassembly thread... - by Manoet - 28-Sep-2015, 17:45
RE: D200 Reassembly thread... - by Jean-Marie - 28-Sep-2015, 18:54
RE: D200 Reassembly thread... - by kenreau - 28-Sep-2015, 19:21
RE: D200 Reassembly thread... - by Manoet - 28-Sep-2015, 19:36
RE: D200 Reassembly thread... - by Vincent - 28-Sep-2015, 19:44
RE: D200 Reassembly thread... - by Manoet - 28-Sep-2015, 20:08
RE: D200 Reassembly thread... - by Manoet - 28-Sep-2015, 20:09
RE: D200 Reassembly thread... - by Manoet - 28-Sep-2015, 20:11
RE: D200 Reassembly thread... - by Manoet - 28-Sep-2015, 20:19
RE: D200 Reassembly thread... - by Teliaved - 28-Sep-2015, 21:23

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