Boy, I have the worst of luck. I think Murphy follows me around. I won't bore you with the details about my recently dropped by Fedex service monitor and major repair cost. The 3457A arrived. Other than missing feet, it looked in decent condition. I powered it up and that is when things went wrong. The first several times, on power up, I got the Address display and the beep, but instead of going to DCV, it displayed PASSED, with an occasional FAILED. It would do this seemingly forever. Once, it powered up normally, then froze. Another time, it powered up normally and I managed to read the error code (1 - Hardware error) and the auxilliarly error (1 - Isolation error durring normal operation). Later, it would power up and immediately display FAILED. At this time, I happened to lift the front of the cabinet and saw that FAILED and PASSED would randomly alternate on the display. Something is definitely loose. I would have already opened the DMM up, except the seller applied anti-tamper labels to the case screws (I have a 30 day warranty). I have sent all of this information to the seller. Hopefully, he will authorize me to open the case and see what is what. Otherwise, I have no choice but to return the DMM. Joe Gray W5JG

I got the OK to open the 3457A. I didn't see anything that was obviously loose or broken. I reseated all connectors and also the socketed ROM. It now powers up and passes self test (at least twice so far). I did all this over lunch, so tonight I will be taking an even closer look at things. While I had it open, I looked it over a bit. All the chips are dated late 1991 or early 1992. The old optocoupler has been replaced by two chips that span the slot in the board. The battery looks like it is probably original. The solder connections don't look re-done. The battery is a Panasonic BR-2/3AE2SP. The tab on one end has one point, the other end has two. Mouser sells these for $5.24. Joe Gray W5JG On Wed, Aug 21, 2013 at 5:34 PM, Joseph Gray <jgray@zianet.com> wrote: > Boy, I have the worst of luck. I think Murphy follows me around. I won't > bore you with the details about my recently dropped by Fedex service > monitor and major repair cost. > > The 3457A arrived. Other than missing feet, it looked in decent condition. > I powered it up and that is when things went wrong. > > The first several times, on power up, I got the Address display and the > beep, but instead of going to DCV, it displayed PASSED, with an occasional > FAILED. It would do this seemingly forever. > > Once, it powered up normally, then froze. Another time, it powered up > normally and I managed to read the error code (1 - Hardware error) and the > auxilliarly error (1 - Isolation error durring normal operation). > > Later, it would power up and immediately display FAILED. At this time, I > happened to lift the front of the cabinet and saw that FAILED and PASSED > would randomly alternate on the display. Something is definitely loose. > > I would have already opened the DMM up, except the seller applied > anti-tamper labels to the case screws (I have a 30 day warranty). I have > sent all of this information to the seller. Hopefully, he will authorize me > to open the case and see what is what. Otherwise, I have no choice but to > return the DMM. > > Joe Gray > W5JG > >

I see that it is allready discontinued. Any idea why and are there schematics around.

It did work until I put everything back together. Now it is back with the same HARDWARE ERROR. I'm going to have to do a full tear down and take a very hard look at everything. The seller told me that this was his personal bench meter for the last four years and that it was working 100% before he shipped it. I have no reason to doubt that. I suspect that something got jarred in shipping and is either loose or shorted. I hope it isn't a cracked trace. I read the CALNUM and it was 34. There are remnants of anti-tamper labels on some case screws from these guys: http://www.ssclabdivision.com. So, it has perhaps been calibrated/adjusted at least once since manufacture. I downloaded the Scope of Accreditation document for the above lab. Am I interpreting things incorrectly, or do the uncertainties for DC voltage source (in particular) look large? One very odd thing that I noticed when it was open was the remnants of a wire that had been tack soldered to what looks like a voltage regulator. See the picture here: https://dl.dropboxusercontent.com/u/19599147/HP%203457A%20Oddity.jpg Joe Gray W5JG On Thu, Aug 22, 2013 at 1:31 PM, Joseph Gray <jgray@zianet.com> wrote: > I got the OK to open the 3457A. I didn't see anything that was obviously > loose or broken. I reseated all connectors and also the socketed ROM. It > now powers up and passes self test (at least twice so far). I did all this > over lunch, so tonight I will be taking an even closer look at things. > > While I had it open, I looked it over a bit. All the chips are dated late > 1991 or early 1992. The old optocoupler has been replaced by two chips that > span the slot in the board. > > The battery looks like it is probably original. The solder connections > don't look re-done. The battery is a Panasonic BR-2/3AE2SP. The tab on one > end has one point, the other end has two. Mouser sells these for $5.24. > > Joe Gray > W5JG > > > > On Wed, Aug 21, 2013 at 5:34 PM, Joseph Gray <jgray@zianet.com> wrote: > >> Boy, I have the worst of luck. I think Murphy follows me around. I won't >> bore you with the details about my recently dropped by Fedex service >> monitor and major repair cost. >> >> The 3457A arrived. Other than missing feet, it looked in decent >> condition. I powered it up and that is when things went wrong. >> >> The first several times, on power up, I got the Address display and the >> beep, but instead of going to DCV, it displayed PASSED, with an occasional >> FAILED. It would do this seemingly forever. >> >> Once, it powered up normally, then froze. Another time, it powered up >> normally and I managed to read the error code (1 - Hardware error) and the >> auxilliarly error (1 - Isolation error durring normal operation). >> >> Later, it would power up and immediately display FAILED. At this time, I >> happened to lift the front of the cabinet and saw that FAILED and PASSED >> would randomly alternate on the display. Something is definitely loose. >> >> I would have already opened the DMM up, except the seller applied >> anti-tamper labels to the case screws (I have a 30 day warranty). I have >> sent all of this information to the seller. Hopefully, he will authorize me >> to open the case and see what is what. Otherwise, I have no choice but to >> return the DMM. >> >> Joe Gray >> W5JG >> >> >