Randy, I doubt, that your hp unit is defective, as it might work under certain circumstances, and also the FW version 8.2 vs. 9.2 will not make any difference, as only a few pair of bytes are different. All versions of the A5 board are designed to be completely interchangeable over all versions of 3458A instruments. I have another theory, which deals with the hardware version difference between the agilent and the hp unit. Your agilent unit might already have the 66547, full SMD board for A5, whereas the hp will for sure have one of the old 66505/515, through- hole boards, Rev A, B, or C. Illya has all of them pictured in his first 3458A repair blog. All the  old versions (A, B, C) have GPIB bus transceivers, TI 75ALS160 for the data bus, and NS 75161 for the handshake signals. The new SMD board has TI 75ALS160 / TI 75ALS161, instead. So, the handshake bus uses a different logic family for the new board, and therefore, the logic levels / immunity might be slightly different. My hp3458A has got the REV C A5 board, and it's from 2000. Since 2009, I run a similar datalogging program for capturing LTZ1000 output versus time, each 4 seconds, on an old PC with WIN98, Turbo Pascal,  an XT bus GPIB card from CEC, with the NEC chip. This program and hardware ran properly for years, (decades), until more and more errors during the 24h acquisition runs occured, vaguely reminding me of your trouble. The output values were always correct, but frequently, 10sec time-outs ocurred, giving zero readings in the datalog. This time-out is obviously related to the handshaking mechanism. Finally, I found out, that the old ATX PSU was failing, especially its input snubber network was gone defect, which probably created big EMC spikes. After replacing the PSU, all these errors vanished completely. My conclusion was, that the GPIB bus is susceptible to such EMC disturbances, although it's solid TTL logic. As obviously the handshake signals were affected only, their higher susceptibility to disturbances may be caused by the difference in the logic family of the transceiver IC. The agilent 3458A might be more tolerant to that, having the ALS161 version, instead. So you might also look for EMC problems in your lab, like SMPS, LED lamps, or a defective PC power supply. Maybe, these Prologix adaptors (clones?) have critical logic levels, especially on the handshake bus, or an improper ground. You might search for these signal problems directly on the GPIB cable. Frank

Randy, I put together a quick script for testing your connection. I have emailed it to you but attached it here for others if needed. It will be easier than running the other program. Todd On Sun, Dec 31, 2017 at 9:00 AM, Dr. Frank <frank.stellmach@freenet.de> wrote: > Randy, > > I doubt, that your hp unit is defective, as it might work under certain > circumstances, and also the FW version 8.2 vs. 9.2 will not make any > difference, as only a few pair of bytes are different. All versions of the > A5 board are designed to be completely interchangeable over all versions of > 3458A instruments. > > I have another theory, which deals with the hardware version difference > between the agilent and the hp unit. > > Your agilent unit might already have the 66547, full SMD board for A5, > whereas the hp will for sure have one of the old 66505/515, through- hole > boards, Rev A, B, or C. Illya has all of them pictured in his first 3458A > repair blog. > > All the old versions (A, B, C) have GPIB bus transceivers, TI 75ALS160 > for the data bus, and NS 75161 for the handshake signals. > The new SMD board has TI 75ALS160 / TI 75ALS161, instead. > > So, the handshake bus uses a different logic family for the new board, and > therefore, the logic levels / immunity might be slightly different. > > My hp3458A has got the REV C A5 board, and it's from 2000. > Since 2009, I run a similar datalogging program for capturing LTZ1000 > output versus time, each 4 seconds, on an old PC with WIN98, Turbo Pascal, > an XT bus GPIB card from CEC, with the NEC chip. > > This program and hardware ran properly for years, (decades), until more > and more errors during the 24h acquisition runs occured, vaguely reminding > me of your trouble. > The output values were always correct, but frequently, 10sec time-outs > ocurred, giving zero readings in the datalog. This time-out is obviously > related to the handshaking mechanism. > Finally, I found out, that the old ATX PSU was failing, especially its > input snubber network was gone defect, which probably created big EMC > spikes. > After replacing the PSU, all these errors vanished completely. > > My conclusion was, that the GPIB bus is susceptible to such EMC > disturbances, although it's solid TTL logic. > As obviously the handshake signals were affected only, their higher > susceptibility to disturbances may be caused by the difference in the logic > family of the transceiver IC. The agilent 3458A might be more tolerant to > that, having the ALS161 version, instead. > > So you might also look for EMC problems in your lab, like SMPS, LED lamps, > or a defective PC power supply. > > Maybe, these Prologix adaptors (clones?) have critical logic levels, > especially on the handshake bus, or an improper ground. > You might search for these signal problems directly on the GPIB cable. > > Frank > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/volt-nuts > and follow the instructions there. >

Todd, The routine looks like this on the Output Console: HP3458A 24.4 0 1 The 0 pops up after several seconds and the 1 after even more seconds later. No other output after the 1. The temperature reading is OK but no voltage readings. Thanks for the assistance but I likely have a hardware issue. I did the service note 13A test and the unit passed it fine. I will have to do more troubleshooting on my own but I really appreciate the help. Randy Evans. On Sun, Dec 31, 2017 at 6:09 AM, Todd Micallef <tmicallef@gmail.com> wrote: > Randy, > > I put together a quick script for testing your connection. I have emailed > it to you but attached it here for others if needed. It will be easier than > running the other program. > > Todd > > On Sun, Dec 31, 2017 at 9:00 AM, Dr. Frank <frank.stellmach@freenet.de> > wrote: > > > Randy, > > > > I doubt, that your hp unit is defective, as it might work under certain > > circumstances, and also the FW version 8.2 vs. 9.2 will not make any > > difference, as only a few pair of bytes are different. All versions of > the > > A5 board are designed to be completely interchangeable over all versions > of > > 3458A instruments. > > > > I have another theory, which deals with the hardware version difference > > between the agilent and the hp unit. > > > > Your agilent unit might already have the 66547, full SMD board for A5, > > whereas the hp will for sure have one of the old 66505/515, through- hole > > boards, Rev A, B, or C. Illya has all of them pictured in his first 3458A > > repair blog. > > > > All the old versions (A, B, C) have GPIB bus transceivers, TI 75ALS160 > > for the data bus, and NS 75161 for the handshake signals. > > The new SMD board has TI 75ALS160 / TI 75ALS161, instead. > > > > So, the handshake bus uses a different logic family for the new board, > and > > therefore, the logic levels / immunity might be slightly different. > > > > My hp3458A has got the REV C A5 board, and it's from 2000. > > Since 2009, I run a similar datalogging program for capturing LTZ1000 > > output versus time, each 4 seconds, on an old PC with WIN98, Turbo > Pascal, > > an XT bus GPIB card from CEC, with the NEC chip. > > > > This program and hardware ran properly for years, (decades), until more > > and more errors during the 24h acquisition runs occured, vaguely > reminding > > me of your trouble. > > The output values were always correct, but frequently, 10sec time-outs > > ocurred, giving zero readings in the datalog. This time-out is obviously > > related to the handshaking mechanism. > > Finally, I found out, that the old ATX PSU was failing, especially its > > input snubber network was gone defect, which probably created big EMC > > spikes. > > After replacing the PSU, all these errors vanished completely. > > > > My conclusion was, that the GPIB bus is susceptible to such EMC > > disturbances, although it's solid TTL logic. > > As obviously the handshake signals were affected only, their higher > > susceptibility to disturbances may be caused by the difference in the > logic > > family of the transceiver IC. The agilent 3458A might be more tolerant to > > that, having the ALS161 version, instead. > > > > So you might also look for EMC problems in your lab, like SMPS, LED > lamps, > > or a defective PC power supply. > > > > Maybe, these Prologix adaptors (clones?) have critical logic levels, > > especially on the handshake bus, or an improper ground. > > You might search for these signal problems directly on the GPIB cable. > > > > Frank > > > > _______________________________________________ > > volt-nuts mailing list -- volt-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/m > > ailman/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. >