What's involved with putting a newer LCD in an older Tek LCD scope - Page 1
Forum section: electronics / repair

author: Robomeds
author_rank: Frequent Contributor
timestamp: October 23, 2017, 02:56:25 am
content: I'm posting this just to learn from those who might have more experience/knowledge about this sort of subject. From time to time a Tektronix 2000, 1000 or 2x0 series scope will pop up for sale for a cheap price with a broken screen. The black and white screens seemed to be notorious for going cloudy over time. Other times you see a color version with a cracked LCD. These are 320x240 screen and in theory should be very low end by today's standards. However, if you look up replacement part costs they are over $100 for the B&W screens used in things like the TDS210 and over $200 for the color 2002 screen. I get that exact replacements are probably expensive but how hard would it be to get a more recent, same resolution screen and swap it in? I know a few people who know far more about this than I do have replaced Tek color CRTs with LCDs in the TDS500 machines. I know basically nothing about this so I'm curious what would be involved with swapping a new LCD into the system. Alternatively, what would be involved in creating a VGA interface and thus using a larger LCD screen as the display?Please forgive the naive nature of the question, this is totally out of my area of expertise so I'm as much interested in knowing "here is why this is hard" as anything. I would certainly understand that say converting the LCD's digital signals to a VGA's analog specs may not be an easy thing unless someone already makes just the right part for that job.This question was inspired by this scope on ebayhttps://www.ebay.com/itm/Tektronix-TDS2002-DIGITAL-OSCILLOSCOPE-60-MHZ-1GS-S-2-CH-In-need-of-repair/272897985731?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D48475%26meid%3Da23415e9eb5c425c9235d98f1f7f016b%26pid%3D100678%26rk%3D1%26rkt%3D15%26sd%3D272897985731&_trksid=p2481888.c100678.m3607&_trkparms=pageci%253A62d341c5-b79d-11e7-b508-74dbd1807c1a%257Cparentrq%253A47267c0315f0a9c56c210433fffc2d85%257Ciid%253A1I understand this scope wouldn't be worth spending much money on given a used Rigol can be had for around $200. However, I do like buying things off ebay for the challenge of "can I fix it" and is the price cheep enough just in case I looseThanks!

author: Rerouter
author_rank: Super Contributor
timestamp: October 23, 2017, 06:47:24 am
content: The main thing would be matching the LCD controller IC, if you can match that, then you don't need to reinvent the wheel, the built in code of the scope will be able to talk to it providing the same signals are broken out.If its custom, then you would need some glue logic, between the scope and your new LCD to format the commands and data to suite. which would involve figuring out the original protocol,

author: kc7gr-15
author_rank: Contributor
timestamp: October 23, 2017, 10:36:06 pm
content: I just finished replacing the CRT in my TDS784D with an LCD panel kit from these nice folks.http://simmconnlabs.com/Without seeing the guts of the particular model(s) you describe, I would have a tough time even guessing at what's involved with replacing a defective LCD in a 'scope which was designed for an LCD from the ground up. I will say Simmconn's LCD kits were created for the express purpose of replacing existing CRT displays, rather than redoing existing LCDs.Happy hunting.

author: Robomeds
author_rank: Frequent Contributor
timestamp: October 24, 2017, 03:20:28 am
content: Quote from: kc7gr-15 on October 23, 2017, 10:36:06 pmI would assume this could be somewhat easier since there is likely quite a bit of hardware designed to take analog signals and port them to LCDs. I kind of suspected what Rerouter suggested was true, you simply can't assume the digital interface protocols are the same. The scope I was looking at on Ebay is now over $50 which means if I had to spend $100 to fix it I'm not getting much for my money. Don't get me wrong, I have fond memories of using Tek scopes from that generation and your TDS700 generation (I really liked those scopes but may not have known better at the time). However, I've also read enough reviews to figure if I'm going to sink any amount of money into a scope it shouldn't be a 1000 or 2000 series Tek.(I recently sunk about $100 into an Agilent 56421A so I'm not in need of anything new)

author: cncjerry
author_rank: Unknown
timestamp: November 01, 2017, 12:53:28 am
content: I have a Tek 744 upgraded to 784 and was wondering about the display going bad over time. I like the old scope and actually love the color depth in the masked OEM, not to start a debate again. Anyway, how does the resolution compare old vs new?JerryQuote from: kc7gr-15 on October 23, 2017, 10:36:06 pm

author: texaspyro
author_rank: Super Contributor
timestamp: November 01, 2017, 01:40:29 am
content: If you have any old pieces of test equipment, keep checking Ebay for replacement displays at a good price. Too many pieces of fine test equipment seem to meet there demise just because of a bad display (LCD, VFD, CRT)I found a guy selling NOS screens for Tek 1000/2000/3000 scopes for $90 and snagged one... so did a lot of other people... they went quickly. Used ones seem to be normally offered for $300 .. $900.I've bought replacement displays for equipment that I don't even own... but might want to own and have known display failure modes.