Electronics > Repair
Rohde & Schwarz SMIQ03B with Error 110 Output unleveled; IQMOD: ALC failure
<< < (3/12) > >>
rastro:
Hello Michel,

That's great news!  Thanks for posting pictures of the repair.  If you suspect any RF noise issues later you may be able to fill in the cut out shield by soldering in some thin copper sheet.  It's probably not an issue.

Regarding the display:
I saw some talk on the yahoo HP blog that someone successfully fixed his HP and RS system by replacing the Cold Cathode Fluorescent Lamp (CCFL).  Various sizes are available on eBay.  The CCFL inverter would be another candidate - universal replacements are also available.

Also thread in eevblog: https://www.eevblog.com/forum/testgear/rohde-schwarz-fsiq-7-signal-analyser-screen-not-working/

Regards
-rastro
sorenkir:
Hi rastro,
You are right, replacement CCFLs can be found on the Internet.
Accessing the 2 CCFLs seems easy but requires to fully disassemble the display and I am not sure I want to disturb this glued ribbon cable...
Michel.
rastro:
Hello Michel,

Yeah, they don't make it easy.  I would also be hesitant to put stress on the ribbon cable connection.  Those connections seem pretty delicate.  I appears you have to bend the tabs to remove the panel also. 

I'm not sure but I thought I saw some information that some of the models/units of RS displays are interchangeable.  Maybe a CMD test set that is obsolete.  I would probably be hard to be certain.

Regards
-rastro
sorenkir:
Exact! I have a another german device (Wandel & Goltermann SF-60) that uses the same display, but it has a few black lines, probably due to the glued ribbon cable...
May be I will try to fix it one day, as Dave does in a video for a Fluke Scopemeter.
Michel.
rastro:
Michel,

Good detective work finding a comprable display.  Too bad it's not 100%.  I saw Dave's video.  It was a good attempt but with mixed results - there has to be a better way.

Some further thoughts on display repairs:

1. I wonder if one of these "Home Sealing Impulse Heat Tool" could be hacked to reflow the solder or reactivate the glue on these troublesome LCD ribbon cables?  It looks like these have a heating element riding on a spongy heat resistant pad - so it may provide better contact with the faulty area.  The heat element is small enough that you could work on one area at a time.  They are certainly cheap enough to experiment with.  I have not seen anyone else try this - who knows...
Example:
Mini Bag Sealer Home Sealing Machine Heat Tool Impulse
http://www.ebay.com/itm/Mini-Bag-Sealer-Home-Sealing-Machine-Heat-Tool-Impulse-Food-Packaging-Fashion-/252052218343?hash=item3aaf7ba1e7:g:rhMAAOSw3ydVyBUh

2. If you go the route of changing the CCFL it may be possible to add a strain relief where the cable meets the PCB.  On either side of the cable there is a hole in the PCB.  Maybe a threaded hook on both ends to clamp down a metal strap and thin piece of rubber in contact with the cable. 

Still, you've made pretty good progress on this instrument!

Regards
-rastro
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod