TECHNET Archives

January 2012

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Brian Ellis <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Brian Ellis <[log in to unmask]>
Date:
Mon, 9 Jan 2012 18:33:20 +0200
Content-Type:
text/plain
Parts/Attachments:
text/plain (88 lines)
Perhaps not ingress of contaminants, but the tinning flux is often 
poorly removed (also in my book)

Brian

On 09/01/2012 18:10, Temkin, Gregg wrote:
> The wires of an incandescent are generally made of Dumet wire which has a good CTE match to glass and also promotes wetting of molten glass to the wire which creates the seal.  An incandescent bulb is a hermetic device.  It is completely sealed unless it's defective.  There is generally no opportunity for ingress of contaminates.
>
> Gregg
>
> -----Original Message-----
> From: Robert Kondner [mailto:[log in to unmask]]
> Sent: Monday, January 09, 2012 8:03 AM
> To: 'TechNet E-Mail Forum'; Temkin, Gregg
> Subject: RE: [TN] Cleaning water soluble flux‏
>
> On the incandescent lights:
>
>    I do recall seeing various flux residues on the soldered connections used in bulbs. I wonder what flux someone might use or what is trapped inside the base where the wires come out of the glass envelope? Once soldered the base is sealed. Could there be an OA flux in there?
>
> Bob K.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Temkin, Gregg
> Sent: Monday, January 09, 2012 10:46 AM
> To: [log in to unmask]
> Subject: Re: [TN] Cleaning water soluble flux‏
>
> I worked for 18 years at a cockpit display manufacturer, working with miniature T1 lamps.  I'd have a hard time saying right off the bat that cleanliness issues with the PWB is causing incandescent bulbs to not light unless sensitive drive circuitry is resident on the same board (which is not often the case).  There are dozens of causes that should be run to ground before looking at cleanliness of the PWB.
>
> Gregg
>
>
> -----Original Message-----
> From: Gary Bremer [mailto:[log in to unmask]]
> Sent: Saturday, January 07, 2012 3:37 PM
> To: [log in to unmask]
> Subject: Re: [TN] Cleaning water soluble flux‏
>
> I am presently working as an contractor for the next few months then back to unemployment, last place I worked was Jet Propulsion Laboratory on the Mars Science Laboratory.  These are lighted panels for various aircraft and the company policy is for J-STD-001/IPC-A-610 Class 3  The failure is with miniature T-1 lamps that stop working after going through an baking process.  Other boards that use these lamps but use RMA flux do not have this problem, I suspect the cleaning process and the flux.  They do not check ionic contamination and handle the boards with bare hands and the operators even know when components are ESD sensitive or not.  I have recommended they change the cleaning process to an Aqueous type batch cleaner but this cost money which they do not wish to spend.  Their process person believes that their process is fine and something else is causing the problem (bad lamps, forming lamp leads, etc.).  This goes against all my knowledge and training.
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 16.0 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 For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
> -----------------------------------------------------
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud service.
> For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________
>
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 16.0 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 For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
> -----------------------------------------------------
>
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud service.
> For more information please contact helpdesk at x2960 or [log in to unmask]
> ______________________________________________________________________
>
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 16.0
> 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
> For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
> -----------------------------------------------------


______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
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
For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------


ATOM RSS1 RSS2