Fluke 8506A with Error F - Page 1
Forum section: electronics / repair

author: D2236
author_rank: Regular Contributor
timestamp: May 16, 2025, 04:14:54 am
content: Meter shows Error F at power-on. How do you clear this? In this state, it doesn't accept any DC cal value corrections via the store button in cal mode. Strangely, it accepts the zero correcting values for each DC range. It works except on 10 V range reads a bit high.According to the manual, it is some check-sum error with the cal memory. Will this need to be replaced?Error F Cal Memory check-sum problem.

author: m k
author_rank: Super Contributor
timestamp: May 19, 2025, 08:01:24 pm
content: Appendix 7B of Instruction Manual has Software Calibration.7-52 is Comprehensive Clear.Is the previous state known?Maybe somebody interrupted previous CAL incorrectly.

author: bdunham7
author_rank: Super Contributor
timestamp: May 19, 2025, 08:44:12 pm
content: You'll need to do the comprehensive clear as found in section 7B-10 (software calibration appendix) and then the meter will need a complete recalibration. If clearing it doesn't eliminate the error code, then you would need to repair the controller board and possibly replace the cal memory.

author: D2236
author_rank: Regular Contributor
timestamp: May 19, 2025, 09:44:11 pm
content: Thanks, that did the trick! It cleared the error.Now I must just perform the full re-calibration.

author: D2236
author_rank: Regular Contributor
timestamp: May 20, 2025, 06:45:52 am
content: After running through the whole calibration, everything looks good on all ranges. No more Error F at power-on.

author: bdunham7
author_rank: Super Contributor
timestamp: May 20, 2025, 01:01:10 pm
content: Quote from: D2236 on May 20, 2025, 06:45:52 amWhat equipment do you have that you can calibrate this meter?

author: D2236
author_rank: Regular Contributor
timestamp: May 20, 2025, 04:52:01 pm
content: I have access to a lab with various types of equipment, including calibrated 7.5 digit DMM's An older Fluke 5100B meter calibrator was used mainly in conjunction with a Keithley 2001 and Advantest R6871E.Furthermore, available was a set of 0.01% precision resistors to cover the ranges up to 100 Meg. All the calibrations for DC/AC volts were pretty painless.The resistance calibrations got me confused as apparently when in CAL, all correction entries showed up with negative "-" sign. Even when you made a measurement while in CAL mode, it will show as -XX ohms. This wasted unnecessary time, because I performed another total clear losing all my voltage calibrations in the process. The negative readings for ohms in CAL mode remained. I completed the procedure and luckily once you switch out of CAL back to normal operation, the "-" sign disappeared. The calibration for AC voltage was a bit more challenging, but at the end the unit measured well within the specifications when compared to the 7.5 digit meters used for verification.This meter is used in non-critical measurements in the lab, so it is good enough for now.

author: tatel
author_rank: Frequent Contributor
timestamp: May 21, 2025, 10:43:16 am
content: Quote from: D2236 on May 20, 2025, 04:52:01 pmNot that I want to be finicky, but after looking at K2001 specs, best AC volts accuracy would be 0,03%?8506A's would be 0,012% So K2001, even if 7 1/2 and in-cal, wouldn't be good enough to calibrate 8506A in AC volts. Don't know about the AdvantestOf course, if this is for non-critical measurements, and it happens there's a spare 8506A to do these, that's fine.Looking at it because I recently got F8506A. But I think I'll leave AC volts as they are now. They don't look bad.

author: daisizhou
author_rank: Super Contributor
timestamp: May 21, 2025, 10:54:01 am
content: Quote from: D2236 on May 20, 2025, 04:52:01 pmCan you tell me what standard source you use for calibration of your AC voltage?

author: D2236
author_rank: Regular Contributor
timestamp: May 21, 2025, 05:07:48 pm
content: Yes, for the AC voltage calibration above 30 Vrms I am the least confidant about. I used the 5100B in parallel with the 2001 and the final readings compared good-enough in my view. I may be able to get my hands on a better Fluke AC calibrator through some friends and redo this when time permits. This specific 8506A is used for DC measurements, 95% of the time.

author: D2236
author_rank: Regular Contributor
timestamp: May 21, 2025, 07:19:18 pm
content: Today I found a 60 Hz transformer out of a scrapped mass-spectrometer's emissions regulator. This has one winding producing around 800 Vrms. There are other windings rated at 12 Vrms. So I used a good Siglent function generator together with an HP 467A power amp (good up to 1 MHz) to drive the low voltage winding. As a result, I got very stable AC voltage outputs to do the 120 Vrms and 500 Vrms ranges. There was no problem up to 10 kHz. On 100 kHz, the transformer fell flat and could only output around 200 Vrms. The AC signals seemed much more stable to those from the 5100B.

author: D2236
author_rank: Regular Contributor
timestamp: May 22, 2025, 04:58:09 pm
content: I managed to generate 300 Vrms at 100 kHz with using the transformer out of the well-known YH11068A. It needed a bit more drive current than the HP 467A could supply, so another power amp JUNTEK DPA-1698 was used. The transformer is designed to run at 75 kHz in the YH11068A module, and at 100 kHz could reach 300 Vrms. To get 500 Vrms, I had to drop the frequency to about 80 kHz on the function gen. For some reason, the JUNTEK didn't like the load at 100 KHz and kept tripping into protection.These items are available widely on Aliexpress, eBay etc.Note: For the YH11068A, make sure youget the one with dual outputs, because you want to the voltage from the two series connected windings. I am not sure if the single output model come with the second winding, but is left unconnected to the pcb. I only have some of the dual output modules.