Calibration Error on Fluke 8808A - Page 1
Forum section: electronics / testgear

author: Balaur
author_rank: Unknown
timestamp: May 21, 2014, 12:17:18 pm
content: Dear all,I'm eyeing a Fluke 8808A on a national listing site. The multimeter has the calibration error indicator lit and the seal broken.The seller says that everything seems to work correctly when compared to a Fluke 187 and there are some photos to prove that.The calibration manual says that the error will appear if a function wasn't calibrated correctly during the full process. Do you have any idea about recurring/usual fault modes on this model that could cause cal errors?Considering the low price and the experience of the seller, I'm inclined to believe that there are serious troubles with the device.BTW, could a 8808A user tell us whether the relays clicking constantly on the dual view modes are uncomfortable?Any ideas and tips will be greatly appreciated. Thank you!Best regards,Dan

author: jpb
author_rank: Super Contributor
timestamp: May 21, 2014, 12:28:03 pm
content: Quote from: Balaur on May 21, 2014, 12:17:18 pmI don't own one so can't help on your main question.The reviewer on the Element14 site (for the Tektronix equivalent) said he did find the relays clicking annoying but perhaps that review is why you asked the question in the first place?http://www.element14.com/community/roadTestReviews/1398

author: Balaur
author_rank: Unknown
timestamp: May 21, 2014, 12:29:35 pm
content: Quote from: jpb on May 21, 2014, 12:28:03 pmExactly!

author: Balaur
author_rank: Unknown
timestamp: June 10, 2014, 04:22:59 pm
content: I've bought it finally and it arrived today. Rather good condition cosmetically on the outside.When opened, it looks like somebody tried to exchange the electrolytic capacitors in the supply. Why? Any issues with capacitors on this Fluke model (the production year is 2009, btw). That's strange.All functions but resistance works as expected and are in very good agreement with an Agilent HP34410A.The smallest resistance range doesn't work (it shows OL always) and it's enough to throw off the auto ranging in some cases. However, the other ranges work correctly.Your tips and ideas will be hugely appreciated. While very much improbable, are there any service manuals or schematics around?Thank you,Dan

author: Zad
author_rank: Super Contributor
timestamp: June 10, 2014, 05:03:03 pm
content: That would be my review thenThe relays only clunk when you are measuring 2 parameters together, for example voltage and current. It needs to reconfigure itself for each measurement as it only has one ADC. I was unable to find a schematic, but I didn't spend a huge amount of time looking.I'm surprised they changed the capacitors, from memory they were all premium brand ones and it all runs cool, even when left on all day. Maybe there was a mains surge which took out the PSU?Nice meter, looks the part and for my money VFD displays like this are easier to read than LCD.

author: jpb
author_rank: Super Contributor
timestamp: June 10, 2014, 05:07:27 pm
content: Quote from: Balaur on June 10, 2014, 04:22:59 pmThere is a lot of debate on this, but my Advantest manual for example recommends that electrolytic capacitors are replaced every 5 years as a precautionary measure.I replaced all the electrolytics in my Advantest when I got it and it turned out to be much harder than I expected as the solder was old and I hadn't yet discovered the trick of mixing in fresh solder.I suspect something like this happened in your case - someone started with the good intention of trying to replace the electrolytics and then didn't complete the job because it was not vital - just a precaution - and it had turned out to be more awkward than they expected.

author: Balaur
author_rank: Unknown
timestamp: June 10, 2014, 07:03:10 pm
content: Hey Zad,Thank you very much for your nice and detailed review. Much appreciated!Yes, the screen is very nice to look at. Crisp, close to the panel and at just the good brightness.Hey jpb,Quote from: jpb on June 10, 2014, 05:07:27 pmYep, you are certainly right. I've reflowed some of the more butchered joints and I had to use a nice massive tip and a bit more heat than usual.Thank you,Dan