Speaking of Oscilloscopes - diyAudio
Go Back   Home > Forums > Design & Build > Equipment & Tools

Equipment & Tools From test equipment to hand tools

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 10th October 2010, 10:02 PM   #1
capnbob is offline capnbob  United States
diyAudio Member
 
Join Date: Jun 2010
Location: Wilmington, NC
Default Speaking of Oscilloscopes

I bought a new dual trace Tenma 30MHz Oscilloscope with an LCD Frequency counter (model number 72-6802) from MCM Electronics in December 2007. It worked fine until a few months ago when the LCD display started losing parts of the numbers. Now it is impossible to read the numbers. I contacted MCM who checked and even though it is a current model, they say that the LCD display is not available as a replacement part. So, I don't know what to do. Anyone have any ideas on how to repair it?
  Reply With Quote
Old 10th October 2010, 10:43 PM   #2
diyAudio Member
 
Join Date: Sep 2004
Location: Minneapolis, Minnesota, USA
Hi Capnbob

Most of the LCD units I've seen have electrical contacts made of dense conductive foam rubber that tend to compress and shrink over time. I had the same problem with my Fluke DVM. I fixed it by first cleaning the contact surfaces with denatured alcohol, then adding shims of thin plastic made from a thin, non-conductive plastic sheet to put more pressure on the contacts. I did that about 2 years ago, and it's been working fine ever since.

Hope that helps.
  Reply With Quote
Old 10th October 2010, 10:57 PM   #3
richiem is offline richiem  United States
diyAudio Member
 
richiem's Avatar
 
Join Date: Sep 2010
Location: Grapeview, WA
Michael's advice is spot on. Clean both of the rubber contact bar and the display's contact area with the denatured alcohol.
  Reply With Quote
Old 11th October 2010, 10:33 PM   #4
capnbob is offline capnbob  United States
diyAudio Member
 
Join Date: Jun 2010
Location: Wilmington, NC
Thanks for the advice. This display is molded into a small metal frame that has hard wired multi-pin connectors on the back. I can easily remove the display unit, but cannot separate the display from the frame with the pinouts on the back. It is a small part and I am surprised that I cannot find a replaement part. Anyone else have problems getting parts for Tenma products? I can't believe that MCM treats the Oscilloscope like a toaster.
  Reply With Quote
Old 12th October 2010, 08:43 PM   #5
richiem is offline richiem  United States
diyAudio Member
 
richiem's Avatar
 
Join Date: Sep 2010
Location: Grapeview, WA
Well, they just import the stuff, nothing more. There's probably a replacement display that will work or can be made to work, but the details need to be known -- what the pin connections are, etc.
  Reply With Quote
Old 11th April 2011, 05:52 AM   #6
diyAudio Member
 
Join Date: Apr 2011
Hi Capnbob! I am Atomkid and new to this forum. I also same with you who brought this Oscilloscope and the LCD Display segment/numbering out until unreadable. So how is your solution and what's the current condition? Solve? Any replacement parts?
I have email to Farnell and bring up this issue for market claims matter. Now still waiting the reply.
  Reply With Quote
Old 12th April 2011, 10:40 PM   #7
cliffyk is offline cliffyk  United States
diyAudio Member
 
cliffyk's Avatar
 
Join Date: Nov 2009
Such displays of that vintage fall in to two broad functional categories, "dumb" raster driven components that display dots where they are told to by external circuitry--and "smart" displays that display, typically from internal bitmaps, what they are told to via commands delivered by a host device (typically via serial connections).

The first thing to do is determine into which of these categories the display falls, and then seek out potential replacements based on the functional category.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need help from Polish-speaking member Nisbeth Everything Else 2 21st February 2007 12:47 AM
Speaking of postings... Sch3mat1c Everything Else 5 23rd July 2003 05:47 AM
Speaking of notebooks jackinnj Everything Else 1 22nd December 2002 09:28 PM
Speaking of remotes.. Sawzall Everything Else 3 24th August 2001 08:25 AM


New To Site? Need Help?

All times are GMT. The time now is 11:05 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2