I think sleeping on the USS Cincinnati (SSN-693) was the best. No wave action to interrupt the gently vibrations on the screw. Just had to watch out when they were training new helmsmen/planesmen they would take the submarine to high angles 30 degrees or so. Since most bunks were for/aft direction you would end up standing on your head. Jerry -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dwight Mattix Sent: Wednesday, September 23, 2009 11:28 AM To: [log in to unmask] Subject: Re: [TN] Knock, knock, knock on the heaven's door slept like a baby right at the waterline just above #2 screw on Connie (CV-64) many, many nights. Does that explain that bad filling in my tooth? :-) At 05:50 AM 9/23/2009, Hernefjord Ingemar wrote: >Jerry, > >slowly, a picture begins to form in my mind. >When I was in the NAVY, I slept as a baby even at full spead >(Destroyer), because the engine was twin steam turbines. Only vibration >was a little from the propeller shaft. The last years, I have taken my >family across the sea on a big RO-RO. THAT was a difference! >Everything was vibrating. Coffee cups rotated on the plates, every >chair had its own life, moved slowly like a snail, not to talk about >the bed, that was hanging on the wall. I went through minimum and >maximum nodes all the night, depending on difference in the rotation >speed of the two main engines. You are right. Transportation on the >sea means passing a vibration test. I am adding yours and Guenter's >posting to the staff. In a few days, a group of technicians are being >sent to fix the problems. I will do my best to get them understand. > >Thanks > >Inge > > >-----Original Message----- >From: TechNet [mailto:[log in to unmask]] On Behalf Of Jerry Dengler >Sent: onsdag 23 september 2009 13:47 >To: [log in to unmask] >Subject: Re: [TN] Knock, knock, knock on the heaven's door > >Hi Inge, > >We produced a product in the US for the US market that used a socket >for a PLCC. This product's usage went up and the customer sent the >production to China. At first all was well. After the production got >to normal levels, suddenly they were getting a high level of out of box >failures. These were all sent via ship. The earlier units were being >air freighted in while the factory in China got up to speed. We found >fretting at the socket to lead interface. We believe it is vibration >from the ship that causes it. > >Recently the factory in China made 1000 units. 500 were air freighted >and 500 were sent via ship. We left the 500 units sent by air on the >skid until the ocean units arrived. We then tested all 1000 units. >122 of the ocean units failed. None of the air units failed. > >Jerry > >-----Original Message----- >From: TechNet [mailto:[log in to unmask]] On Behalf Of Hernefjord Ingemar >Sent: Wednesday, September 23, 2009 5:59 AM >To: [log in to unmask] >Subject: Re: [TN] Knock, knock, knock on the heaven's door > >Hi Guenter, >interesting. Very interesting. You got fretting issues at 28 Hz? Caused >by floor vibration? >Really? I've been involved in several fretting problems (aircrafts), >but then we had much higher frequencies, maybe multiples of lower >resonances. Our equipments were transported by ship to the other side >of the planet, and it was then the problems started. I'll check how >they were transported, time at sea etc. > >Thanks again > >/inge > >PS. What level of vibration? > > >-----Original Message----- >From: TechNet [mailto:[log in to unmask]] On Behalf Of Grossmann, Guenter >Sent: onsdag 23 september 2009 09:41 >To: [log in to unmask] >Subject: [TN] AW: [TN] Knock, knock, knock on the heaven's door > >Hi Inge > >Vibrations around? I just had recently a similar problem in an >industrial environment. Failure analysis showed fretting on socket >spring- contacts. When I made vibration measurements I found quite a >spectrum of low level vibrations on the floor but a clear resonance at >28Hz in the rack. > >Best regards > >Guenter > > > > >-----Ursprüngliche Nachricht----- > >Von: TechNet [mailto:[log in to unmask]] Im Auftrag von Inge > >Gesendet: Dienstag, 22. September 2009 21:34 > >An: [log in to unmask] > >Betreff: [TN] Knock, knock, knock on the heaven's door > > > >Well, not exactly that, but knock, knock, knock on a earthly board. > >One customer needs fix a intermittent problem asap. 19 inch racks > >with hundreds of PTH double sided boards, old technology, no BGAs, no > >QFMs etc, but lots, lots of DIPs. The edge contact fingers have a > >very thick and good gold over nickel, and the backplane connectors > >have really stiff double tongues. > >The > >contact pressure/sq is extremly high and I think the contact spots > >are really gastight once the board is plugged in. Now, they have > >electrical issues, and they've found, that the signals are > >interrupted or coming back when they knock on the boards. Someone is > >going to take a flight the other day to fix the problem. The > >electricians believe, stubborn as mules, that the only think needed, > >is to take out the boards and clean the edge contact fingers with a > >solvent and that will fix it. Myself, with quite many year's > >experience from connectors, I don't think that is the problem, > >because when such robust contact springs wipe along the contact > >fingers, they slide pretty deep into the gold and makes good > >connection. Each spring has double contact ridges, so the risk that > >some dirt should cause interrupts is minimal. There is more that > >talks against their theory, namely, that the problem is still there > >after plugging, deplugging more than once. I'm sure there is a solder joint issue, or maybe a bond wire problem in the packages. > >Logically, this later is more likely because you have thousands of > >solder/bond joints vs, just some one hundred edge connector ditto. A > >ratio like 10,000/100 per board. Without knowing all details, what is > >your general experience between the index finger and the big toe? > > > >/Inge > > > >--------------------------------------------------- > >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 >----------------------------------------------------- > >--------------------------------------------------- >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 >----------------------------------------------------- > >--------------------------------------------------- >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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------