HELP FLUKE 8846 - Page 1
Forum section: electronics / repair

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 10, 2021, 09:19:11 am
content: Good morning all! I recently recovered a FLUKE 8846, and it is broken; it displays on all ranges: overload (measurement overflow). After opening and visual inspection; I noticed that transistor Q41 had its box exploded, the resistance network R242 had burned, and by completely disassembling the multimeter, I also saw that below the diode CR67 had also exploded ... I removed U64, U71, U67, U74, and the various small diodes and transistors around which were defective, I could read the inscriptions on their boxes ...... But except for these 3 burnt components ... I attached the various photos. ..... Could someone help me ?? (FLUKE does not give a schematic, so you have to find solutions yourself) ... Thank you very much for your help!

author: gamalot
author_rank: Super Contributor
timestamp: March 10, 2021, 02:19:45 pm
content: Try this:https://xdevs.com/fix/f8846a/

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 10, 2021, 03:31:24 pm
content: Hello; thank you, but I have already looked before, I only have photos, taken quite far away, which therefore do not give any indication of the burnt components .... Cdt

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 11, 2021, 11:55:49 am
content: help me!

author: chekhov
author_rank: Regular Contributor
timestamp: March 11, 2021, 01:03:04 pm
content: Except U69 which has a yellow dot on it, pictures at xdevs contain a lot of details, maybe you are looking at wrong place ? Photos shown in article are not all that exist, look carefully.

author: gamalot
author_rank: Super Contributor
timestamp: March 11, 2021, 02:42:43 pm
content: Quote from: chekhov on March 11, 2021, 01:03:04 pmU69 is ST's M25P40VP SPI interface EEPROM.

author: gamalot
author_rank: Super Contributor
timestamp: March 11, 2021, 02:58:00 pm
content: Resistor pack R242

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 13, 2021, 11:10:47 am
content: Hello; okay; thank you very much for finding the R242 resistor network! But for the others, I have already magnified the image, but there is dust on the components; I can't do it! It remains to identify: Q41, CR67: thanks for your help!

author: gamalot
author_rank: Super Contributor
timestamp: March 13, 2021, 01:01:05 pm
content: For your reference only, I am pretty sure CR67 is BAT54S, for Q41 I guess it should be DTC144EKA.

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 15, 2021, 03:16:38 pm
content: Good evening, and a big thank you to "gamalot" for his help! I have 1 component left for which I still need help, it is transistor Q44 (the marking is illegible because it has heated up) ?? Thank you for your feedback ..... Cdt

author: gamalot
author_rank: Super Contributor
timestamp: March 15, 2021, 03:50:01 pm
content: Q44 is PMBFJ109:https://www.nxp.com/docs/en/data-sheet/PMBFJ108_109_110.pdf

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 16, 2021, 02:15:54 pm
content: Hello; thank you all for your help, and especially to "gamalot" who allowed me to identify these components!

author: EddyInChicago
author_rank: Contributor
timestamp: April 25, 2021, 11:48:55 pm
content: Hi All,Gamalot; the PMBFJ109 is obsolete. Is there a suitable jfet to use there?Thanks,Ed