Good points. The RHOS lead free solder issues also lead me to favour older gear.
On Fri Oct 22nd, 2010 9:25 AM EDT paul swed wrote: >I have picked up and repaired for my own use many pieces of HP and other >high end equipment and what you are running into is almost the first thing I >check. Though actually my first steps are a careful visual inspection then >measure the power supplies looking for shorts. (Most likely from caps) >HP5386 that nicad battery is a disaster. When they go, very common in what >we buy (I have 5 3586s at the moment) they spew gook onto the regulators. >Worse if powered up in that condition the stuff arcs across and burns >traces. Very tough to clean up and repair at that point. >Back to the general comments. >What I am seeing in more modern gear is its the tantalums that are nasty. >They blow up and cause a lot of damage to the surrounding area. I just >picked up a SRS FS700 loran receiver and 2 had gone south. I replaced with >more traditional electrolytics. >Slightly higher voltage and capacitance. > >Lastly I am afraid even if newer gear shows up that we can afford. Between >smt devices and special chips and 4 plus layer non traceable boards repair >is extremely difficult. Just when you think you have it all going you find >out some software is missing. >Afraid I will be eternally locked to to the 70s-90s for equipment. >Regards >Paul. > >On Fri, Oct 22, 2010 at 6:59 AM, Bob Camp <[email protected]> wrote: > >> Hi >> >> If the pass element in the regulator has the emitter towards the load you >> probably are fine fiddling with the cap. If the collector is towards the >> load - check it with a scope. >> >> Bob >> >> >> On Oct 22, 2010, at 5:31 AM, Hal Murray wrote: >> >> > >> >> However I plan on replacing all the axial types in all of my HP >> equipment, >> >> except for the tantalums, with new 105C, low ripple, high reliability >> types. >> > >> > How does today's "low ripple" compare with back when the gear was >> designed? >> > >> > Some regulators oscillate without enough ESR in the big filter caps. I >> > wonder if that might turn into a problem with old gear. >> > >> > >> > >> > -- >> > These are my opinions, not necessarily my employer's. I hate spam. >> > >> > >> > >> > >> > _______________________________________________ >> > time-nuts mailing list -- [email protected] >> > To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> > and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >_______________________________________________ >time-nuts mailing list -- [email protected] >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
