Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to sci.electronics.repair
Michael Kennedy
 
Posts: n/a
Default Help Guessing at Capacitor Values..

I have a LCD controler that has some heat sensitive ceramic caps on it. The
problem is they are SMD caps and have no markings at all. I bought the
service manual for the sony sdm-hs73 monitor but it has no schematics..
err...

So with some educated guessing I was hoping we could figure this out.. The
caps are directly connected to a Genesis GM2121 I.C. So I thought with the
data sheet for the GM1212 that someone might be able to help me guess at
what rating of capacitor I should use..

All of the refrences to caps in the manual are from 2 to 9pf for inputs..
and 16pf for outputs..

Pictures of the board
http://mikescomputers.homeip.net/LCD/DSC00388.JPG
http://mikescomputers.homeip.net/LCD/DSC00390.JPG
http://mikescomputers.homeip.net/LCD/DSC00392.JPG

Genesis GM1212 Datasheet
http://www.keil.com/dd/docs/datashts.../gm2121_ds.pdf
Quick way to get to cap values it search for pf

Thanks in advace..

- Mike


  #2   Report Post  
Posted to sci.electronics.repair
Adrian C
 
Posts: n/a
Default Help Guessing at Capacitor Values..

Michael Kennedy wrote:

Genesis GM1212 Datasheet
http://www.keil.com/dd/docs/datashts.../gm2121_ds.pdf
Quick way to get to cap values it search for pf


Nope, wrong search method :-)

The value you are looking at doing the above search is the internal
'looking in' capacitance of the chip, for input and output ports!

The parts you are interested in (surrounded by the yellow box) are
connected to pins 130 to 136 are in the RGB input channels described on
page 23 of the data sheet, the value given is 0.01uF (10nF). Having
littered circuit boards with plenty of these SMD components in my time,
and looking at your photographs at the size of things - my gut feeling
is that 10nF is the value you should try.

--
Adrian C
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT +1. The time now is 06:42 PM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"