Broken Fluke Scopemeter 99

[zitrex2]

Hi,
I just got Fluke scopemeter 99 series II. I have problem with it. This thing is quite shy and don't want to display anything on its "LCD". In short words - scopemeter don't show anything on display. It's not completely dead, because when I click auto set button I can hear relay clicks and also backlight is working. No obvious damage on PCB.

Somone tried to repair contrast regulation block. I see some flux on PCB and some not very professional soldering. Here you have pics of it.

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Here you have service manual for Fluke 93/95/97:
http://bee.mif.pg.gda.pl/ciasteczkowypotwor/Philips/pm93_95_97_fluke_93_95_97.pdf

If someone have service manual for 99 model please, post it here.
Thank you for suggestions and your time.

Sorry for my english it's not my native language.

 

[D.A.(Tony)Stewart]

Is this your recent purchase of a '96 vintage LCD scope or you are the lucky repair guy?

If no imag, then something may be wrong with the contrast signal. Look for a square wave 0-5V which then gets level shift towards -20V thru an R ladder then each buffered V1,V2..V6

I think the way it works is each 4 bit data chip is used to as a DAC selector with the voltages added to create different contast levels for each pixel. Since LCD's use differential video, this then becomes the differential signal fed to each selected pixel which are sequentially addressed like a raster scan TV.

 

[zitrex2]

I'm not pro repair guy. Friend gave it to me. In first words after reading your post - Oh my God If i had osciloscope I would check that 5V signal ... Now problem in half solved. I just figured out that soldering on LM and Power supply needs good hand (not mine but i think im enough for this scope) Guys You ll never guess what was wrong. Soldering ! Scope is alive now. It's taking 350mA with backlight. Backlight Uin=90V. Crazy repair! Thanks for your pro sugestion. Lucky noob guy huh ?

 

[zitrex2]

Now I see that this scopemeter have 2 not working buttons ("move chanel B trace down" and "lower Time base") Carbon tape looks ok, carbon pads are not damaged. Soldering joints conecting tape and PCB look also ok.

 

[D.A.(Tony)Stewart]

Now that you have a working scope,

I wonder if you can trace the signals on those buttons.
:-D

 

[zitrex2]

Those soft buttons ... I checked them with ohms range with Fluke 87 (ahh that latching beep, great stuff) and it's clear now that this keyboard is matrix one and those buttons that are not working should not work, because there are no continuity between them and "their" string. But how ...

 

[zitrex2]

Problem solved with 0,2mm wire and copper tape. I tried to fix traces with carbon-glue but I almost ate my teeth when doing it. It's pure madness. This stuff should be forbiden by Geneva Convention.

 

[onurbayın]

Problem solved with 0,2mm wire and copper tape. I tried to fix traces with carbon-glue but I almost ate my teeth when doing it. It's pure madness. This stuff should be forbiden by Geneva Convention.

hello
I have the same problem in the product .
Exactly what is the solution?
helps , sun ?
What do I need to intervene in the section ?