[volt-nuts] HP419A Meter Pegged to Right
I'm trying to bring an HP419A back to life. I managed to replace the corroded nicads with two obsolete power tool 13.2v nicad packs. The bucking cell, I swapped for an LR50 alkaline. When fired up, the meter pins to the right. Randy Evans posted elsewhere the same problem with his 419. Perhaps this is a pattern failure due to the battery salts that have invaded the instrument. Anywhere these salts have worked on a non-noble metal, the corrosion is permanent. There was a good deal of salting on the main amp board connector...easily removed from the gold plating with an abrasive eraser. Numerous component lead to solder joint areas are corroded, but in no way has the corrosion worked its way to the point of opening connections. I can spot faint pools of salts right on the FR4. I would like to wash the board in water. I can plastic wrap the pots which are all ganged in the upper right of the board, but I'm not sure what a water wash would do to the composition resistors, and the electrolytics. Since I'm certain there must be salt all over the board that is invisible, mechanical removal of visible salts would be an exercise in futility. Any votes for a water wash? Any better ideas? BTW the neons are shot. That's another big unknown. My first take is to try and replace them. I have on order NE-2Us, and NE-83s. These are better for photoconductor illumination due to having more radioactive Krypton than NE-2Hs...Very important to fight the Dark Effect. Unfortunately, I suspect the original neons were probably custom manufactured for HP chopper work. We'll just have to see Stan ___ 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] HP419A Meter Pegged to Right
If you're talking about washing the board only, I'd say go for it. Just run the hottest tap water on it, and a little liquid dishwashing detergent, and scrub it thoroughly with an old toothbrush. Then lots of rinsing and drying - compressed air can knock out a lot water from parts that may trap some. If any greenish films persist you may want to pour vinegar over it, scrub it, then repeat the above process. Just make sure that any final washing step is with an alkaline (detergent) - not acidic - material. If battery juice has worked into the board edge connector, you may have to flush it out too. Ed At 07:28 PM 11/10/2014, you wrote: I'm trying to bring an HP419A back to life. I managed to replace the corroded nicads with two obsolete power tool 13.2v nicad packs. The bucking cell, I swapped for an LR50 alkaline. When fired up, the meter pins to the right. Randy Evans posted elsewhere the same problem with his 419. Perhaps this is a pattern failure due to the battery salts that have invaded the instrument. Anywhere these salts have worked on a non-noble metal, the corrosion is permanent. There was a good deal of salting on the main amp board connector...easily removed from the gold plating with an abrasive eraser. Numerous component lead to solder joint areas are corroded, but in no way has the corrosion worked its way to the point of opening connections. I can spot faint pools of salts right on the FR4. I would like to wash the board in water. I can plastic wrap the pots which are all ganged in the upper right of the board, but I'm not sure what a water wash would do to the composition resistors, and the electrolytics. Since I'm certain there must be salt all over the board that is invisible, mechanical removal of visible salts would be an exercise in futility. Any votes for a water wash? Any better ideas? BTW the neons are shot. That's another big unknown. My first take is to try and replace them. I have on order NE-2Us, and NE-83s. These are better for photoconductor illumination due to having more radioactive Krypton than NE-2Hs...Very important to fight the Dark Effect. Unfortunately, I suspect the original neons were probably custom manufactured for HP chopper work. We'll just have to see Stan ___ 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] HP419A Meter Pegged to Right
And should you be prepared to remove the pots, you could run it through the dishwasher ... (if it works for Bob Pease, it works for me too). Regards, David Partridge -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of ed breya Sent: 11 November 2014 07:44 To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] HP419A Meter Pegged to Right If you're talking about washing the board only, I'd say go for it. : : Ed At 07:28 PM 11/10/2014, you wrote: >I'm trying to bring an HP419A back to life. >: >: > >Any votes for a water wash? Any better ideas? > ___ 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] HP419A Meter Pegged to Right
Hi: My second oscilloscope was a new Tek 515 which I got for the student price and picked up from the Tek sales office on San Antonio Rd in Palo Alto. On the tour they showed me the washing booth where they used a water soap solution to spray wash the complete scope. There were no parts in the design that would absorb water. When washing semiconductor wafers after the DI water rinse they used an alcohol rinse then a compressed clean air blow off. The alcohol sucks up the water and what small amount that's left after the air evaporates quickly. Mail_Attachment -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html David C. Partridge wrote: And should you be prepared to remove the pots, you could run it through the dishwasher ... (if it works for Bob Pease, it works for me too). Regards, David Partridge -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of ed breya Sent: 11 November 2014 07:44 To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] HP419A Meter Pegged to Right If you're talking about washing the board only, I'd say go for it. : : Ed At 07:28 PM 11/10/2014, you wrote: I'm trying to bring an HP419A back to life. : : Any votes for a water wash? Any better ideas? ___ 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] HP419A Meter Pegged to Right
That clinches it. Brooke's Tek tour reminded me that I have on file a "Service Scope" from Tek entitled "Washing Your Tektronix Equipment". I can follow those instructions less the drying for 24 hours in an oven at 125F. Doing so will probably have me kicked out of the house by the wife. A hair dryer will have to suffice. The use of a dishwasher, which I could pull off without being found out by my spouse, does require removing all the pots. Anyway, I think that dishwashing is most appropriate for boards with all surface mount chips. Forty year old electrolytics (all of which surprisingly have tested good) might balk at being machine washed. Stan On Tue, Nov 11, 2014 at 11:34 AM, Brooke Clarke wrote: > Hi: > > My second oscilloscope was a new Tek 515 which I got for the student price > and picked up from the Tek sales office on San Antonio Rd in Palo Alto. On > the tour they showed me the washing booth where they used a water soap > solution to spray wash the complete scope. There were no parts in the > design that would absorb water. > > When washing semiconductor wafers after the DI water rinse they used an > alcohol rinse then a compressed clean air blow off. The alcohol sucks up > the water and what small amount that's left after the air evaporates > quickly. > > Mail_Attachment -- > Have Fun, > > Brooke Clarke > http://www.PRC68.com > http://www.end2partygovernment.com/2012Issues.html > http://www.prc68.com/I/DietNutrition.html > > David C. Partridge wrote: > >> And should you be prepared to remove the pots, you could run it through >> the dishwasher ... (if it works for Bob Pease, it works for me too). >> >> Regards, >> David Partridge >> -Original Message- >> From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of ed breya >> Sent: 11 November 2014 07:44 >> To: Discussion of precise voltage measurement >> Subject: Re: [volt-nuts] HP419A Meter Pegged to Right >> >> If you're talking about washing the board only, I'd say go for it. >> : >> : >> >> Ed >> >> At 07:28 PM 11/10/2014, you wrote: >> >>> I'm trying to bring an HP419A back to life. >>> : >>> : >>> >>> Any votes for a water wash? Any better ideas? >>> >>> ___ >> 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] HP419A Meter Pegged to Right
There are certain things that must be done/considered before washing old electronics: 1) remember there is lots of lead that might not be wanted in your dishwasher. If you choose to use the DW, buy a lead test pen for afterwards. 2) tek always suggested removing the paper insulator tubes from the old FP style of can electrolytic cap prior to washing. 3) a large cardbord box, with a 60W incandescent light bulb, and a muffin fan makes a dandy convection oven for drying washed electronics. There should be a couple of holes in the box to allow moisture to vent out, and fresh air in. 4) electronics can't tell when you get it too hot, unlike your head, be careful with the hair dryer. It can easily get parts hot enough to damage them. 5) power transformers don't like being exposed to water and especially to detergent. Detergent inside of a power transformer can instantly turn a working CRT filament winding into one that has a low resistance leak to another winding/ground. Many a power transformer has been ruined that way. 6) a dishwasher is a deluge of water, more prudent cleaning is done with a gentle shower of water, directed towards parts that don't mind getting wet, and away from parts that do. -Chuck Harris Stan Katz wrote: That clinches it. Brooke's Tek tour reminded me that I have on file a "Service Scope" from Tek entitled "Washing Your Tektronix Equipment". I can follow those instructions less the drying for 24 hours in an oven at 125F. Doing so will probably have me kicked out of the house by the wife. A hair dryer will have to suffice. The use of a dishwasher, which I could pull off without being found out by my spouse, does require removing all the pots. Anyway, I think that dishwashing is most appropriate for boards with all surface mount chips. Forty year old electrolytics (all of which surprisingly have tested good) might balk at being machine washed. Stan On Tue, Nov 11, 2014 at 11:34 AM, Brooke Clarke wrote: ___ 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] HP419A Meter Pegged to Right
The sadly missed Kevin Lightner did electronic music synthesizer repair and had an interesting technique for cleaning older electronic circuit boards: http://www.youtube.com/watch?v=DwRlZyIG6rg No chance for oxidation as the boards were dried immediately with compressed air. An amazing amount of spilled beer, cigarette smoke and other crud washing off... Kevin's old website is here: http://www.synthfool.com/oldindex.html Analog music synthesizers are somewhat on-topic as every parameter is voltage controlled and in the case of frequency (an exponential function) the requirements are very very precise. The voltage applied is one volt per octave change and errors of 0.2% can be detected easily. Voltage stability is also important as these modules need to track over normal room temperature fluctuations. Dave > -Original Message- > From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf > Of Chuck Harris > Sent: Tuesday, November 11, 2014 21:17 > To: Discussion of precise voltage measurement > Subject: Re: [volt-nuts] HP419A Meter Pegged to Right > > There are certain things that must be done/considered before > washing old electronics: > > 1) remember there is lots of lead that might not be wanted in > your dishwasher. If you choose to use the DW, buy a lead > test pen for afterwards. > 2) tek always suggested removing the paper insulator tubes from > the old FP style of can electrolytic cap prior to washing. > 3) a large cardbord box, with a 60W incandescent light bulb, and > a muffin fan makes a dandy convection oven for drying washed > electronics. There should be a couple of holes in the box > to allow moisture to vent out, and fresh air in. > 4) electronics can't tell when you get it too hot, unlike your > head, be careful with the hair dryer. It can easily get > parts hot enough to damage them. > 5) power transformers don't like being exposed to water and > especially to detergent. Detergent inside of a power > transformer can instantly turn a working CRT filament > winding into one that has a low resistance leak to another > winding/ground. Many a power transformer has been ruined > that way. > 6) a dishwasher is a deluge of water, more prudent cleaning > is done with a gentle shower of water, directed towards > parts that don't mind getting wet, and away from parts that > do. > > -Chuck Harris > > Stan Katz wrote: > > That clinches it. Brooke's Tek tour reminded me that I have > on file a > > "Service Scope" from Tek entitled "Washing Your Tektronix > Equipment". I can > > follow those instructions less the drying for 24 hours in > an oven at 125F. > > Doing so will probably have me kicked out of the house by > the wife. A hair > > dryer will have to suffice. > > > > The use of a dishwasher, which I could pull off without > being found out by > > my spouse, does require removing all the pots. Anyway, I think that > > dishwashing is most appropriate for boards with all surface > mount chips. > > Forty year old electrolytics (all of which surprisingly > have tested good) > > might balk at being machine washed. > > > > Stan > > > > On Tue, Nov 11, 2014 at 11:34 AM, Brooke Clarke > wrote: > > > ___ > 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] HP419A Meter Pegged to Right
On 11/11/2014 22:42, Stan Katz wrote: That clinches it. Brooke's Tek tour reminded me that I have on file a "Service Scope" from Tek entitled "Washing Your Tektronix Equipment". I can follow those instructions less the drying for 24 hours in an oven at 125F. Doing so will probably have me kicked out of the house by the wife. A hair dryer will have to suffice. The use of a dishwasher, which I could pull off without being found out by my spouse, does require removing all the pots. Anyway, I think that dishwashing is most appropriate for boards with all surface mount chips. Forty year old electrolytics (all of which surprisingly have tested good) might balk at being machine washed. Stan On Tue, Nov 11, 2014 at 11:34 AM, Brooke Clarke wrote: Hi: My second oscilloscope was a new Tek 515 which I got for the student price and picked up from the Tek sales office on San Antonio Rd in Palo Alto. On the tour they showed me the washing booth where they used a water soap solution to spray wash the complete scope. There were no parts in the design that would absorb water. When washing semiconductor wafers after the DI water rinse they used an alcohol rinse then a compressed clean air blow off. The alcohol sucks up the water and what small amount that's left after the air evaporates quickly. Mail_Attachment -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html David C. Partridge wrote: And should you be prepared to remove the pots, you could run it through the dishwasher ... (if it works for Bob Pease, it works for me too). Regards, David Partridge -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of ed breya Sent: 11 November 2014 07:44 To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] HP419A Meter Pegged to Right If you're talking about washing the board only, I'd say go for it. : : Ed At 07:28 PM 11/10/2014, you wrote: I'm trying to bring an HP419A back to life. : : Any votes for a water wash? Any better ideas? ___ A quick wash down with pure isopropyl alcohol afer the wash will help draw out a lot of the residual water. Some sources of IPA seem to have a significant meths content as in the past a bad batch crazed some polystyrene capacitors, so check before use on a whole board. ___ 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.
