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Re: 3457a on the way
Steve, Jeff, and all,
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According to the manual, the 'New Main Controller' was installed starting at SN 2538A02954 and later. The Assembly Number, 03457-665xx, etc., is under the power transformer and difficult to see but there. Also, regarding the 'new' battery and 'new' resistors, the manual states 'the new parts are on assembly A11, ERC no. 2850 and greater' which I interpret to mean SN 2850Axxxxx and greater. The 'New Main Controller' is easy to identify by just looking at where the battery is located. Looking from the front of the meter, with the top cover off and the 'shield' over the main controller off, the 'old' controller had the battery to the left side of the board, near the left side of the meter, about half way back from the front while the 'new' main controller has the battery on the right side of the board, near the center of the meter, about one fourth of the way back from the front. So, if I am correct, my SAFT LX-1634 3.0 V battery represents the 'old' 2.9 volt battery although my battery does not state what the chemistry of the battery is. Therefore, if I can find an exact replacement of the battery, chemistry and all, I would prefer to just replace the battery rather than place a new battery and resistors. Also, the PCB is manufactured so as to provide mounting for a battery with one positive and one negative pin as well as a battery with one positive and two negative pins. Therefore, there may be some other options. Has anyone found any information specifically about the SAFT LX-1634 battery? Interestingly, the same SAFT LX-1634 battery is used in the 3478A. I replaced the 3478A battery with a BR-2/3A several months ago with no detectable problems so far but the battery backup circuitry is much simpler than the 3457A. Also, of note, the BR-2/3A reads 3.397 VDC. As best I can tell, the only role for R644 and R645 is during the Power On Reset and the Low Power Reset. It would appear that the Low Power Reset is the only issue of concern. The 'old' components set a level of about 2.99 VDC at the + input of U636A while the 'new' components set a level of about 3.46 VDC at the + input of U636A when the UNREG +5 VDC supply drops to 7 VDC. If no changes in resistors were made, the same 3.46 VDC would occur when the UNREG +5 VDC supply dropped to about 8.1 VDC. I measure 11.18 VDC on my UNREG +5 VDC supply. Therefore, I can't see a compelling reason to change the resistors. The Power On Reset is released later and the Low Power Reset is applied earlier if all you do is replace the SAFT LX-1634 with a BR-2/3A. Would this be a problem? Am I missing something? Thanks for all the help in 2012 and Happy 2013. Joe -----Original Message-----
From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...] On Behalf Of Steve Sent: Monday, December 31, 2012 7:34 PM To: hp_agilent_equipment@... Subject: Re: [hp_agilent_equipment] 3457a on the way Joe and all, I will pop the covers off mine again and have a look at the A1 board revision number and resistor values. Regarding battery voltage, I noticed a couple of web sites state that their lithium batteries are "3.6 v nominal, 3.4 volt operating" I assume that's at their rated current so HP may have been stating operating voltage. I can't imagine that maintaining cal constants would draw much current though. Steve On Dec 31, 2012, at 6:25 PM, "J. L. Trantham" <jltran@... <mailto:jltran%40att.net> > wrote: Steve, Jeff, and all,it measures 3.032 VDC. Likewise, I can not see a date code on the battery,resistors and matches the schematic. The 'new' resistors would be 13 K and 12.7 Ka 'Battery 3V 1.2A-HR Lithium Poly Carbon'. Only the manual parts list listsshould be used?<mailto:hp_agilent_equipment%40yahoogroups.com> [mailto:hp_agilent_equipment@...<mailto:hp_agilent_equipment%40yahoogroups.com> ] On Behalf Of Steve Krull Sent: Monday, December 31, 2012 11:20 AM<mailto:hp_agilent_equipment%40yahoogroups.com> Subject: Re: [hp_agilent_equipment] 3457a on the way<mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com><mailto:hp_agilent_equipment%40yahoogroups.com><mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com><mailto:hp_agilent_equipment%40yahoogroups.com><mailto:hp_agilent_equipment%40yahoogroups.com>] On Behalf Of Steve <mailto:hp_agilent_equipment%40yahoogroups.com>Boeing<mailto:hp_agilent_equipment%40yahoogroups.com> checkMilitary Airplane Company's metrology lab. I need to open it up and <mailto:jltran%40att.net>the battery condition. <mailto:jltran%40att.net><mailto:hp_agilent_equipment%40yahoogroups.com><mailto:jltran%40att.net> <mailto:hp_agilent_equipment%40yahoogroups.com><mailto:hp_agilent_equipment%40yahoogroups.com><mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com><mailto:hp_agilent_equipment%40yahoogroups.com><mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com>for<mailto:hp_agilent_equipment%40yahoogroups.com> goods.the $200 + price tag of calibration. Funny how when I was single Iwouldhave about $800 in cash in my wallet at all times and now I beg for 20comes thenAny feedback would be appreciated as to possible pitfalls regardingthisdevice. I like to prep for issues rather then build myself up for belet down. manual.madeFrequencyon a 3457A, Input Offset Amplifier adjustment and AC ConvertermessageResponse, both needed only if there is a 'HARDWARE ERR' failure'AUXERR' orafter 'TEST' is selected and then only if it is a specificpanel16 or calibration,Interestingly, when I sent my two 3458A's to Agilent for bytheCALNUM incremented by only 1. However, when I calibrated one of them haveallthe data points entered. Such software exists for the 3457A but I thatnever seen it available 'on theBay'. I suspect Agilent would have mysoftware and equipment to do that calibration and, thus, an Agilent Voltage'House CAL' of the one 3458A failed were the two 'midrange' AC CAL.values. All else 'PASSED'. youIfinstrumentsit's Solartron, I prefer AMETEK (Solartron), etc. instruments,have a <mailto:hp_agilent_equipment%40yahoogroups.com>issignalsvery important if you want to set up a reliable workshop. <mailto:hp_agilent_equipment%40yahoogroups.com><mailto:hp_agilent_equipment%40yahoogroups.com><mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com><mailto:hp_agilent_equipment%40yahoogroups.com><mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com><mailto:jeff%40codebest.com><mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:jeff%40codebest.com>a<mailto:jeff%40codebest.com> itbadthing.I thought the bit showing the noise on the DVM was a bit silly when howAgilentwas connected to a DC power supply.As for the 3457A, if it works I plan on getting it calibrated byinvestment.within the year. From what I understand it's about a $200 USThe meter was last calibrated in '98, so I'll be curious to see howaccurate it is when I get it.I think the calibration service you chose might dictate whether you thenmuch. But I'm not going to pay extra for a calibration service that calibrateit is OK. For me personally, it makes no difference whatsoever if it bought.them is not available commerically. So it makes me wonder how a lab way trimmer,outand later getting it NIST traceable calibrated.I don't know if there are pots in there you can adjust with a or if it is all done electronically. You might find it is impossible------------------------------------ |
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