I am currently repairing a Fluke 5200a ac voltage

Hi all, I am currently repairing a Fluke 5200a ac voltage calibrator. After pulling cards in and out and soldering multiple wires on to test I now have the unit working about 98%. Anybody might have or know of where I might be able to obtain an extender card for this unit as it would make it a lot easier to fix the last remaining problem that I have, ie:- I have a dc offset voltage on the output of about 1mv when it should be +/- 100 microvolts. I am unable to adjust this with r26 adjustment on the power amplifier board as described in the manual. I have followed the troubleshooting guides as per the manual, as well as testing just about all the components around that particular part of the circuit. The problem appears to be that the input stage is not being turned on hard enough as all the suggested voltages for the input stage (Q1-2-3-4-5-9) are all too high. The supply voltages are all within spec. Anybody can offer suggestions? Sorry to put this out there in this group but I cannot find an online group related to fluke test equipment to ask. Ken Goodhew. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com

              I am currently repairing a Fluke 5200a ac voltage

Hello Ken, From what I remember of this circuit, R26 is for output stage bias. R6 is for adjusting offset. By the way, which voltages are high and how much? The 5200 is an old beast, expect a lot of marginal electrolytics, carbon resistors that have drifted well out of tolerance and even transistors that no longer perform any where near what they originally did. Regards On 07/07/14 14:56, Ken Goodhew1 wrote: > Hi all, > > I am currently repairing a Fluke 5200a ac voltage > calibrator. > > After pulling cards in and out and soldering multiple wires on to test I now > have the unit working about 98%. > > Anybody might have or know of where I might be able to obtain an extender > card for this unit as it would make it a lot easier to fix the last > remaining problem that I have, ie:- I have a dc offset voltage on the output > of about 1mv when it should be +/- 100 microvolts. > > I am unable to adjust this with r26 adjustment on the power amplifier board > as described in the manual. I have followed the troubleshooting guides as > per the manual, as well as testing just about all the components around that > particular part of the circuit. > > The problem appears to be that the input stage is not being turned on hard > enough as all the suggested voltages for the input stage (Q1-2-3-4-5-9) are > all too high. The supply voltages are all within spec. > > Anybody can offer suggestions? > > Sorry to put this out there in this group but I cannot find an online group > related to fluke test equipment to ask. > > Ken Goodhew. > > > > --- > This email is free from viruses and malware because avast! Antivirus protection is active. > http://www.avast.com > _______________________________________________ > 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. > > -- sig.html *Control Electronics Pty Ltd* The home of Shiftmaster Quality used test equipment *Phone*: 02 9456 0736 *Website*: www.controlelectronics.com.au <http://www.controlelectronics.com.au/>* Email*: admin@controlelectronics.com.au <mailto:admin@controlelectronics.com.au> ABN 86 109 858 022 ------------------------------------------------------------------------ The email addresses in this message are not to be added to any database, list, or mailing list without my prior explicit written permission. This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. Please note that any views or opinions presented in this email are solely those of the author and do not necessarily represent those of the company. Finally, the recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email.

              I am currently repairing a Fluke 5200a ac voltage

The problem is dc offset. On Mon, Jul 7, 2014 at 5:30 PM, Gerd <admin@controlelectronics.com.au> wrote: > Hello Ken, > > From what I remember of this circuit, R26 is for output stage bias. R6 is > for adjusting offset. By the way, which voltages are high and how much? > > The 5200 is an old beast, expect a lot of marginal electrolytics, carbon > resistors that have drifted well out of tolerance and even transistors that > no longer perform any where near what they originally did. > > Regards > > > On 07/07/14 14:56, Ken Goodhew1 wrote: > >> Hi all, >> >> I am currently repairing a Fluke 5200a ac voltage >> calibrator. >> >> After pulling cards in and out and soldering multiple wires on to test I >> now >> have the unit working about 98%. >> >> Anybody might have or know of where I might be able to obtain an extender >> card for this unit as it would make it a lot easier to fix the last >> remaining problem that I have, ie:- I have a dc offset voltage on the >> output >> of about 1mv when it should be +/- 100 microvolts. >> >> I am unable to adjust this with r26 adjustment on the power amplifier >> board >> as described in the manual. I have followed the troubleshooting guides as >> per the manual, as well as testing just about all the components around >> that >> particular part of the circuit. >> >> The problem appears to be that the input stage is not being turned on hard >> enough as all the suggested voltages for the input stage (Q1-2-3-4-5-9) >> are >> all too high. The supply voltages are all within spec. >> >> Anybody can offer suggestions? >> >> Sorry to put this out there in this group but I cannot find an online >> group >> related to fluke test equipment to ask. >> >> Ken Goodhew. >> >> >> >> --- >> This email is free from viruses and malware because avast! Antivirus >> protection is active. >> http://www.avast.com >> _______________________________________________ >> 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. >> >> >> > -- > sig.html *Control Electronics Pty Ltd* > The home of Shiftmaster > Quality used test equipment > *Phone*: 02 9456 0736 > *Website*: www.controlelectronics.com.au <http://www. > controlelectronics.com.au/>* > Email*: admin@controlelectronics.com.au <mailto:admin@ > controlelectronics.com.au> > ABN 86 109 858 022 > ------------------------------------------------------------------------ > The email addresses in this message are not to be added to any database, > list, or mailing list without my prior explicit written permission. This > email and any files transmitted with it are confidential and intended > solely for the use of the individual or entity to whom they are addressed. > If you have received this email in error please notify the system manager. > Please note that any views or opinions presented in this email are solely > those of the author and do not necessarily represent those of the company. > Finally, the recipient should check this email and any attachments for the > presence of viruses. The company accepts no liability for any damage caused > by any virus transmitted by this email. > > _______________________________________________ > 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. > -- John Phillips