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Electronics => Repair => Topic started by: longboard1210 on July 04, 2020, 08:45:30 am

Title: Fluke 867 no power/lcd (Repaired)
Post by: longboard1210 on July 04, 2020, 08:45:30 am
Morning guys

Fluke 867 with no power or no lcd display

the unit appears to be doing something as it has about 0.15a draw from my power supply when turned on

However my 3.3v rail is at 4.2v for some reason VCC

I have ot got stuck into it yet but anybody had ant experiance with the units ?

Title: Re: Fluke 867 no power/lcd
Post by: tooki on July 04, 2020, 11:44:07 am
Following. (I recently found an 867 at work in storage, and it's also not working. It'll power on in some ranges, but is often on the wrong range, and the display has glitches. I cleaned the rotary switch and it made no difference, so I think it's a logic issue. Didn't have a chance to check voltages or anything, and I've put it back in storage for now.)
Title: Re: Fluke 867 no power/lcd
Post by: shakalnokturn on July 05, 2020, 08:55:11 am
@Tooki: I wouldn't be surprised if yours was a case of battery contamination behind the CPU.
Title: Re: Fluke 867 no power/lcd
Post by: shakalnokturn on July 05, 2020, 09:03:22 am
Related topics...

https://www.eevblog.com/forum/testgear/please-help-for-strange-problem-with-fluke-867b-dc-measurement/ (https://www.eevblog.com/forum/testgear/please-help-for-strange-problem-with-fluke-867b-dc-measurement/)

https://www.eevblog.com/forum/repair/after-three-evenings-with-a-fluke-867b/ (https://www.eevblog.com/forum/repair/after-three-evenings-with-a-fluke-867b/)

Title: Re: Fluke 867 no power/lcd
Post by: longboard1210 on July 08, 2020, 03:06:28 pm
Hi thanks but these did not have the same issue

Long story short it helps to read the block diagrams and i mean read and understand them you end up chasing your tail if you dont a quck scan on a screen is not the same

Its been a first for  me usually i do work on the fly witout schematics  and gut feeling always plays a part in diagnosis

When i checked the board over i felt that the voltages were just to high on the board and wouldnt you know it the 2.5v voltage referance that is on the board was outputting 5v  not the 2.5v that the scematicsand the exellent fluke manual  said it should be

so i replaced the voltage reg and she sprang to life  done a few bits of testing and it seems to be pretty good  well fine for what i need anyway

next upgrade i will see if i can throw a decent backlight in there