Re: [volt-nuts] HP 3456A -3 Fault
I agree these caps are the most failure-prone parts in the 3456A, and also the 3455A. Sometimes they also cause damage to other parts like the associated three-terminal regulators. Don't be surprised if there's still more to fix after cap replacement - but usually easy to find. I had one where an LM339 status comparator was shot - I suspected over-voltage or reversal of an input polarity during the cap failure, even though it wasn't obvious how it could have done that. The diagnostics instructions in the manual worked very well and led quickly to the faulty part. Ed ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] HP 3456A -3 Fault - re-cap info
No problem, I just remember how much time I wasted trying to diag intermittent fail 3, 4 and IIRC 10 or always fail but alternates which test fails, etc before I noticed a bulging cap and ran across a posting over in hp_agilent_equipment that set me on the re-capping path. Then I was frustrated by being able to find all the value/spec info for all of the caps but not being able to find original data sheets with lifespan, dimensions and lead spacing... Ended up pulling all the caps from one and measuring while taking notes on available space. Then sat down and spent the evening browsing mouser looking for approp caps from the same series all long life high temp low esr type. A good de-soldering station or gun (I have Hakko gun) and a temp controlled iron will make re-capping easy. I am in the habit of cleaning with isopropal after removal and again after install of new caps. Local grocery pharma section usually has 99% iso in hermetically sealed pint bottles on sale for 99cents every 90 days or so, and I keep a liter of 99.999% anhydrous lab grade for final rinse of high impedance circuits. Not exactly a big deal in a PS, but leftover flux can be corrosive and often absorbs moisture. The PS voltages can be checked in place, and you do really need a scope for ripple. Remember you have + and - supplies, pay very close attention and check voltage/ripple before and after. Make sure to check the large caps as well A10C5 4000uf +100/-10 15vdc (Fat stubby large can on mail supply board) A3C6 12,000uf +75/-10 16vdc (Large axial Sprauge over on A3 5v board) Both of these in all 6 of mine were good, but is worth checking. Outside of a regulator fail with burnt parts involved I have never head of the glass sealed Ta caps (little silver axials) failing. Another common issue is dirty/intermittant on the guard and front/back switches. With top/bottom panels and the adjust panel on is easy to deal with. Dripping iso through switch while slowly cycling switch (cases off unit up on end so drips out) followed by re-lube with deoxit D5 seems to work well. (Deoxit D5 and D10 are 5%/10% deoxit 95%/90% iso). I have small bottle of D100 and mix with iso when needed, generally about 98% iso. Makes application easier, cause I can just apply 10ish drops to switches like the gaurd and 20ish to the larger F/R switch while cycling to make sure to fully penetrate and reach all contacts, but 98% evaps leaving only a very light lube film. On 12/27/14, 15:56, David Smith wrote: > Wow Christopher, Thank You! I'm blown away by your kindness! > I will get two sets of these caps ordered on Monday and see if I can get > these two 3456's back in operation. > Thanks again! > > Dave - W6TE > >> Date: Sat, 27 Dec 2014 15:08:04 -0900 >> From: cbr...@woods.net >> To: volt-nuts@febo.com >> Subject: Re: [volt-nuts] HP 3456A -3 Fault >> >> >> First suspect is always the small electrolytics on A10, followed by the >> large one on A10, and large one on A3, but those last 2 are large/high >> qual and seem to last much better. >> >> >> All 6 of my 3456As had or developed issues with one or more of the small >> caps. >> >> All 6 have been re-capped with >> >> >> >> >> >> A10C7 >> 0180-300947uf ±20 50vdc Al >> Nichicon UPM1J680MPD6 >> >> A10C8 >> 0180-2803100uf +50/-10 50vdc Al >> Nichicon UPM1J331MHD6 >> >> A10C13/A10C15 >> 0180-26351000uf +50/-10 35vdc Al >> Nichicon UPM1V152MHD6 >> >> A10C16 >> 0180-3014330uf ±20 50vdc Al >> Nichicon UPM1J391MHD6 >> >> A10C19 >> 0180-3008470uf +50/-10 35vdc Al >> Nichicon UPM1V681MHD6 >> >> >> These are all direct match for lead spacing/etc except C8, where the >> replacement is wider leads _but_ has a thick slotted base so you can >> dog-leg the leads to match the original spacing. >> >> All are long-life ± 20% parts, all are larger but fall within the >> original range spec except C8, where going from 150uf (originally >> selected part) to 330uf reduced p-p ripple from .45v to < .2v >> >> >> DO check voltage and ripple, but if it comes down to it, the re-cap >> takes about 20 minutes, including removing A10, pre and post recap >> cleaning and re-install. >> >> >> On 12/26/14, 14:34, David Smith wrote: >>> Hello Friends, >>> I have two HP 3456A's that have the same "-3" fault in the "test" mode. >>> Both DVM's started exhibiting this same fault about the same time. I've >>> troubleshot one of the DVM's to a failure in the Isolation Logic >>> &qu
Re: [volt-nuts] HP 3456A -3 Fault
Wow Christopher, Thank You! I'm blown away by your kindness! I will get two sets of these caps ordered on Monday and see if I can get these two 3456's back in operation. Thanks again! Dave - W6TE > Date: Sat, 27 Dec 2014 15:08:04 -0900 > From: cbr...@woods.net > To: volt-nuts@febo.com > Subject: Re: [volt-nuts] HP 3456A -3 Fault > > > First suspect is always the small electrolytics on A10, followed by the > large one on A10, and large one on A3, but those last 2 are large/high > qual and seem to last much better. > > > All 6 of my 3456As had or developed issues with one or more of the small > caps. > > All 6 have been re-capped with > > > > > > A10C7 > 0180-3009 47uf ±20 50vdc Al > Nichicon UPM1J680MPD6 > > A10C8 > 0180-2803 100uf +50/-10 50vdc Al > Nichicon UPM1J331MHD6 > > A10C13/A10C15 > 0180-2635 1000uf +50/-10 35vdc Al > Nichicon UPM1V152MHD6 > > A10C16 > 0180-3014 330uf ±20 50vdc Al > Nichicon UPM1J391MHD6 > > A10C19 > 0180-3008 470uf +50/-10 35vdc Al > Nichicon UPM1V681MHD6 > > > These are all direct match for lead spacing/etc except C8, where the > replacement is wider leads _but_ has a thick slotted base so you can > dog-leg the leads to match the original spacing. > > All are long-life ± 20% parts, all are larger but fall within the > original range spec except C8, where going from 150uf (originally > selected part) to 330uf reduced p-p ripple from .45v to < .2v > > > DO check voltage and ripple, but if it comes down to it, the re-cap > takes about 20 minutes, including removing A10, pre and post recap > cleaning and re-install. > > > On 12/26/14, 14:34, David Smith wrote: > > Hello Friends, > > I have two HP 3456A's that have the same "-3" fault in the "test" mode. > > Both DVM's started exhibiting this same fault about the same time. I've > > troubleshot one of the DVM's to a failure in the Isolation Logic > > "Transmitter." I have no waveform at the output of A3T1. > > Before I continue with troubleshooting I thought I'd ask a question of the > > group. Is there a common mode failure of these DVM? Is there something in > > particular or area that I should be looking at/for? > > It's probably coincidental that they would both fail at about the same time > > with the same -3 fault. > > Your input is greatly appreciated. > > Best regards, > > > > Dave - W6TE > > ___ > > volt-nuts mailing list -- volt-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > and follow the instructions there. > > > ___ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] HP 3456A -3 Fault
First suspect is always the small electrolytics on A10, followed by the large one on A10, and large one on A3, but those last 2 are large/high qual and seem to last much better. All 6 of my 3456As had or developed issues with one or more of the small caps. All 6 have been re-capped with A10C7 0180-3009 47uf ±20 50vdc Al NichiconUPM1J680MPD6 A10C8 0180-2803 100uf +50/-10 50vdc Al NichiconUPM1J331MHD6 A10C13/A10C15 0180-2635 1000uf +50/-10 35vdc Al NichiconUPM1V152MHD6 A10C16 0180-3014 330uf ±20 50vdc Al NichiconUPM1J391MHD6 A10C19 0180-3008 470uf +50/-10 35vdc Al NichiconUPM1V681MHD6 These are all direct match for lead spacing/etc except C8, where the replacement is wider leads _but_ has a thick slotted base so you can dog-leg the leads to match the original spacing. All are long-life ± 20% parts, all are larger but fall within the original range spec except C8, where going from 150uf (originally selected part) to 330uf reduced p-p ripple from .45v to < .2v DO check voltage and ripple, but if it comes down to it, the re-cap takes about 20 minutes, including removing A10, pre and post recap cleaning and re-install. On 12/26/14, 14:34, David Smith wrote: > Hello Friends, > I have two HP 3456A's that have the same "-3" fault in the "test" mode. Both > DVM's started exhibiting this same fault about the same time. I've > troubleshot one of the DVM's to a failure in the Isolation Logic > "Transmitter." I have no waveform at the output of A3T1. > Before I continue with troubleshooting I thought I'd ask a question of the > group. Is there a common mode failure of these DVM? Is there something in > particular or area that I should be looking at/for? > It's probably coincidental that they would both fail at about the same time > with the same -3 fault. > Your input is greatly appreciated. > Best regards, > > Dave - W6TE > ___ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] HP 3456A -3 Fault
Thank you Bill, I'll start looking at the power supplies. Dave - W6TE > From: wpgold3...@att.net > To: volt-nuts@febo.com > Date: Fri, 26 Dec 2014 16:36:00 -0800 > Subject: Re: [volt-nuts] HP 3456A -3 Fault > > Dave: > > These things are NOTORIOUS for filter cap failures in the power > supplies. Check both the voltages and the RIPPLE on the various power > supplies. It is not sufficent to just check the voltages. You must check > the ripple with an o'scope. At least this is the first step before looking > for anything else. > > Good luck, > > Bill > > - Original Message - > From: "David Smith" > To: > Sent: Friday, December 26, 2014 3:34 PM > Subject: [volt-nuts] HP 3456A -3 Fault > > > > Hello Friends, > > I have two HP 3456A's that have the same "-3" fault in the "test" mode. > Both DVM's started exhibiting this same fault about the same time. I've > troubleshot one of the DVM's to a failure in the Isolation Logic > "Transmitter." I have no waveform at the output of A3T1. > > Before I continue with troubleshooting I thought I'd ask a question of the > group. Is there a common mode failure of these DVM? Is there something in > particular or area that I should be looking at/for? > > It's probably coincidental that they would both fail at about the same > time with the same -3 fault. > > Your input is greatly appreciated. > > Best regards, > > > > Dave - W6TE > > ___ > > volt-nuts mailing list -- volt-nuts@febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > and follow the instructions there. > > ___ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] HP 3456A -3 Fault
Dave: These things are NOTORIOUS for filter cap failures in the power supplies. Check both the voltages and the RIPPLE on the various power supplies. It is not sufficent to just check the voltages. You must check the ripple with an o'scope. At least this is the first step before looking for anything else. Good luck, Bill - Original Message - From: "David Smith" To: Sent: Friday, December 26, 2014 3:34 PM Subject: [volt-nuts] HP 3456A -3 Fault > Hello Friends, > I have two HP 3456A's that have the same "-3" fault in the "test" mode. Both DVM's started exhibiting this same fault about the same time. I've troubleshot one of the DVM's to a failure in the Isolation Logic "Transmitter." I have no waveform at the output of A3T1. > Before I continue with troubleshooting I thought I'd ask a question of the group. Is there a common mode failure of these DVM? Is there something in particular or area that I should be looking at/for? > It's probably coincidental that they would both fail at about the same time with the same -3 fault. > Your input is greatly appreciated. > Best regards, > > Dave - W6TE > ___ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
[volt-nuts] HP 3456A -3 Fault
Hello Friends, I have two HP 3456A's that have the same "-3" fault in the "test" mode. Both DVM's started exhibiting this same fault about the same time. I've troubleshot one of the DVM's to a failure in the Isolation Logic "Transmitter." I have no waveform at the output of A3T1. Before I continue with troubleshooting I thought I'd ask a question of the group. Is there a common mode failure of these DVM? Is there something in particular or area that I should be looking at/for? It's probably coincidental that they would both fail at about the same time with the same -3 fault. Your input is greatly appreciated. Best regards, Dave - W6TE ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
