Subject: | |
From: | |
Reply To: | |
Date: | Tue, 18 Sep 2007 13:46:17 -0700 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
trace peel wouldn't be my first (intuitive) concern. I'd be interested in
what that specific "FR4" material is, it's max continuous op temp and
whether the dielectric is decomposing/degrading.
dw
At 10:58 AM 9/18/2007, Croslin, Robert wrote:
>Dear 'Netters,
>
>We have a product used to measure on/off status on flat screen TV's that
>was designed a few years ago. Over time, with the newer, bigger TV's,
>there is a much higher current draw than we'd envisioned way back
>when. So, as the devices cycle back through our repair depot, we're
>making mods to upgrade them to handle these new TV's. A problem we've
>seen in testing is that the traces that handle the AC pass-through are now
>getting quite warm. We've measured the traces at 105*C at room
>temperature. The base is plain old FR4. We haven't been able to get any
>to fail in testing, but are concerned about the differential under load
>possibly causing the trace to peel away from the FR4. Our concern is
>thermal cycling over time; could it cause the trace to lift? If the trace
>is hot but the board cool in a steady state condition, is there any risk there?
>
>Does anyone know of any specifications that would address this situation?
>
>Bob Croslin
>Nielsen Media Research
>
>
>
>---------------------------------------------------
>Technet Mail List provided as a service by IPC using LISTSERV 15.0
>To unsubscribe, send a message to [log in to unmask] with following text in
>the BODY (NOT the subject field): SIGNOFF Technet
>To temporarily halt or (re-start) delivery of Technet send e-mail to
>[log in to unmask]: SET Technet NOMAIL or (MAIL)
>To receive ONE mailing per day of all the posts: send e-mail to
>[log in to unmask]: SET Technet Digest
>Search the archives of previous posts at: http://listserv.ipc.org/archives
>Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
>for additional information, or contact Keach Sasamori at [log in to unmask] or
>847-615-7100 ext.2815
>-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
|
|