Thanks. I did not realize that the CPLD was for ADC control until I re-read Illya's article again, and I then realized with the parts complement present that the "ADC" must be an integrating type. Next time I crack it open, I'll have more to check. Russ On Sun, Jun 26, 2016 at 3:44 PM, Todd Micallef <tmicallef@gmail.com> wrote: > The repair was performed last November and my memory is bad, too many > projects since then. The two defective parts were the TF-245 and U626. > > My symptoms were noisy readings across all ranges. I could not get them to > settle down even with the input shorted. I measured the TF-245 in-circuit > to see if anything was too far out to be in spec. I was certain that the > 30K resistor between 5-11 was open, so I removed it and measured. There was > also another open 90K resistor between 7-8. > > I also had to trace an input signal through the meter and it led to the > resistor array. I will try and find the actual in-circuit measurements > before the part was replaced. > > I > > > Todd > > On Sun, Jun 26, 2016 at 4:23 PM, Russ Ramirez <russ.ramirez@gmail.com> > wrote: > > > Looking forward to your notes Todd. A bit more info on the repair. > > > > DCV1 is OK except for the 10 V range. A test voltage input of 100 mV > > appears on the input side of Q665 fine, but not on the output side in the > > 10 V range, however a DMM measurement is solid in the other applicable > > ranges. So this issue does seem to be completely isolated to the 10 V > > range. > > > > DCV2 input is fine through the path to the ADC (TP652) in all ranges, but > > the unit is not making a stable measurement. For example, a 9 V input > reads > > between 8.8 V and 9.2 V on the 10 V scale. The same 9 V input to DCV1 > also > > looks good up to TP652, on the 100 V range since 10 v is out it, and it > > reads a stable 9.002 V at that TP. Without a schematic, it will take some > > time to determine what is different after the TP652 point - maybe there > are > > in fact 2 ADCs, but it's not obvious either way. > > > > Russ > > > > On Sun, Jun 26, 2016 at 11:16 AM, Todd Micallef <tmicallef@gmail.com> > > wrote: > > > > > I have to review my notes, but I know of the two bad parts that were > > > found, one was the TF-245. I happened to have a spare on hand. I will > > look > > > through any notes to get the other part number. > > > > > > Todd > > > > > > Sent from my iPad > > > > > > > On Jun 26, 2016, at 10:09, Russ Ramirez <russ.ramirez@gmail.com> > > wrote: > > > > > > > > Thanks Illya - very nice piece of work! > > > > > > > > Russ > > > > > > > >> On Sun, Jun 26, 2016 at 5:27 AM, Illya Tsemenko <illya@xdevs.com> > > > wrote: > > > >> > > > >> If you looking into repair or internals detail of 2182, this draft > > > article > > > >> may help: https://xdevs.com/fix/kei2182/ > > > >> Keithley stopped releasing schematics and detailed information since > > > >> xxxx-series instruments due to IP issues. > > > >> > > > >> 26/06/16 18:08, Brian Smith пишет: > > > >> > > > >> Hello Russ > > > >>> > > > >>> It appears that there are neither a service manual nor a schematic > > > >>> available anywhere. > > > >>> > > > >>> My educated guess is that this is because the 2182A is a current > > model > > > >>> instrument. The newest production model keithley gear does not have > > > >>> associated service manuals nor schematics published. These appear > to > > be > > > >>> treated as trade secrets. > > > >>> > > > >>> You can have your 2182A serviced by Keithley if it is in need of > > > repair. > > > >>> > > > >>> I had my model 2000 DMM that I bought from eBay serviced by > Keihtley > > > for > > > >>> $560. They replaced the motherboard bringing the DMM up to brand > new > > > >>> condition. I asked for and received the calibration data with the > > > returned > > > >>> instrument. > > > >>> > > > >>> best regards, > > > >>> > > > >>> Brian > > > >>> > > > >>> > > > >>> > > > >>> On Fri, Jun 24, 2016 at 10:38 PM, Russ Ramirez < > > russ.ramirez@gmail.com > > > > > > > >>> wrote: > > > >>> > > > >>> The service manual, or a schematic. I asked just in case someone > had > > > one > > > >>>> from an original purchase. I also asked a friend who worked for > > > Keithley, > > > >>>> but apparently no one he knew had one either. Hard to find. > > > >>>> > > > >>>> Russ > > > >>>> On Jun 24, 2016 6:26 PM, "Brian Smith" <briansmith23456@gmail.com > > > > > >>>> wrote: > > > >>>> > > > >>>> What document do you need? Keithley publishes most needed docs. > > > >>>>> On Jun 24, 2016 12:59 PM, "Russ Ramirez" <russ.ramirez@gmail.com > > > > > >>>>> wrote: > > > >>>>> > > > >>>>> Just wondering if any of you might have a PDF of the subject > > > >>>>>> > > > >>>>> Nanovoltmeter? > > > >>>>> > > > >>>>>> TIA > > > >>>>>> > > > >>>>>> Russ > > > >>>>>> _______________________________________________ > > > >>>>>> 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. > > > >>>> > > > >>>> _______________________________________________ > > > >>> 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. > > > _______________________________________________ > > > 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. >