Fluke 5700A Repair  - Page 1
Forum section: electronics / repair

author: CrazyTiger
author_rank: Regular Contributor
timestamp: January 19, 2023, 02:07:20 pm
content: Hi,I got my hands on a Fluke 5700A. The calibrator has a strange behavior where the output trips when I turn on EXT sense on Voltage DC and AC and measurements are bad at 4 wire ohms as well, so basically anything to do with Ext Sense is bad.However the instruments works perfect if Ext sense is off. The unit self-test, diagnostics is good. I am yet to open up the instrument, been reading the service manuals preparing for the weekend. Tripping occurs when the the calibrator output is drawing too much current. So likely I am looking for shorted components, but My first two suspected modules will be the motherboard and the switch matrix module. Any other module I should be focusing?

author: Swake
author_rank: Frequent Contributor
timestamp: January 19, 2023, 02:33:38 pm
content: You have to watch the video from Marco Reps about the repair of his 5700A.He also makes a reference to the xDevs website with interesting information on 5700A calibrator review and servicehttps://xdevs.com/fix/f5700a/It is quite an adventure you started there, good luck !

author: CrazyTiger
author_rank: Regular Contributor
timestamp: January 20, 2023, 03:05:28 am
content: Update:Could not sleep yesterday, so woke up middle of the night and tried re-seating all the boards and gently tapping (more like knocking) the relays. Unit now working with sense ON too. But I have noticed while running diagnostic few times, 15S supply seems to fail every now and then, so does Osc A13. However the I don't see obvious changes in DC or AC voltage measurement on my 3458A, but I am yet to run any long term measurement.15V on the A17 module seems good. However ESR is bad on almost all of the capacitors on A17, worst so far is ESR of 100 ohms on those low profile 22uf 35V Cap, both in and off circuit.Based on the circuit, it makes sense this cap might be causing the error on A13.Ordered tonnes of nichicons capacitor, will be recapping all modules, slowly

author: Louis_C
author_rank: Contributor
timestamp: February 03, 2023, 04:03:14 pm
content: I have a Fluke 5700A that self destructed a couple months ago. The unit was sitting idle in the morning after running the self check when we came into the lab. One of the tech's went to use the 5700A and it literally went up in a small cloud of smoke. Long story short, the A18 took the brunt with ALL the capacitors blowing out and taking several cards with it. I managed to get the 5700 up and running with some errors on AC. I went to do the ext cal with a Fluke 732A and input my true value voltage of 10.0001308 VDC. Now, I have a laundry list of errors here (please see attached). I am over my head and don't know what to do now. ANY help, info or prayers would be greatly appreciated. Thank you.Errors in order from internal cal check…With A12 REMOVEDA11 13v reference range fault 2817A11 -11v DC range fault 2811A11 -22 DC range fault 2813A11 6.5v buffer reference fault 2814A11 6.5v reference fault 2815A11 13v buffered reference fault 2816A11 13v reference fault 2817With A12 INSTALLEDDAC monitoring fault 2809A11 13v reference range fault 2817A11 -11v DC range fault 2811A11 -22 DC range fault 2813A11 6.5v buffer reference fault 2814A11 6.5v reference fault 2815A11 13v buffered reference fault 2816A11 13v reference fault 2817A11 ADC amp output offset fault 2807A8 zero amp high gain fault 3809A8 22mv divider fault 3815A8 relay fault 3819A12/A13 DAC 15th bit fault 3416A12 DC sensor buffer fault 3417A12 AC cal sensor 2v range 3421A11 6.5v buffered reference fault 2814A9 diff amp gain fault 3309A9/A10 10 ohm check fault 3331A9/A10 1 ohm check fault 3333A9/A10 1.9 ohm check fault 3334A9/A10 ohms short check fault 3335A9/A10 10 ohm cal diag fault 3315A9/A10 19 ohm cal diag fault 3316A16 pwr amp DC cal network gain fault 3528A16 pwr amp 220v range attenuator fault 3529A167/A14 220v AC range output fault 3508A15 DC HV amp offset fault 3107A15 DC HV amp gain fault 3108A15/A15 HV AV 1khz output fault (LO) 3128A15/A15 HV AV 1khz output fault (MID) 3129A14/A15 HV AC 100hz output fault (LO) 3131A14/A15 HV AC 100hz output fault (MID ) 3132A14/A15 HV AC 100hz output fault (MID ) 3137A14/A15/A16 2.2A AC range abs. fault 3140

author: alm
author_rank: Super Contributor
timestamp: February 03, 2023, 05:03:19 pm
content: Quote from: Louis_C on February 03, 2023, 04:03:14 pmI would recommend opening another topic and leave a link here so we don't have two separate repairs getting confused. Also, it would help if you could describe what you did between the 5700A releasing magic smoke and now. If all the caps blew up on A18, then I would be very worried about anything else that's hanging off the same rail, which depending on the rail might be a lot. I would also be suspicious of any carbon composition resistor in that instrument. Did you read what's been written before on this forum, especially by TiN, and on his site xdevs.com?https://xdevs.com/fix/f5700a/https://xdevs.com/fix/hulk/https://xdevs.com/fix/hulk2https://xdevs.com/fix/hulk3/

author: CrazyTiger
author_rank: Regular Contributor
timestamp: February 17, 2023, 02:46:34 am
content: Update:I have recapped all the electrolytes in the calibrator.Now awaiting for the tantalums and the carbon composition resistors, most of the carbon resistors are way out of tolerance as expected. Element14/Farnel is taking their own sweet time to deliverAnyway I still have an intermittent problem with AC output, Ac output trips, like once in a week. Sometimes it fails diagnose on A14/A16 (220V AC Ranges), A14 checked out good. But on A16 module,I found one transistor shorted.Its weird that even with the transistor shorted, the output is good at high voltages, with and without sense ON. I still need to read up what this section do.Any suggestion for the transistor, MPSh10 is long obsolete.Thanks