Tek 2465BCT question: CRT life? - Page 1
Forum section: electronics / testgear

author: NHnewbie
author_rank: Contributor
timestamp: October 27, 2018, 04:40:32 pm
content: I recently acquired a Tek 2465BCT (sn B063xxx) from an eBay seller who had done an extensive refurb of this unit prior to selling, including recapping, new NVRAM with recent cal data, new fan, etc. Came with nice options (09/10/1E), four P6137 probes, front cover, lots of accessories, comprehensive operator and service manuals. Cosmetics could pass for new and all checks pass. One minor surprise: the hour "meter" shows about 7100 hours. What should I expect (in hours) for the life of the CRT?BTW: The seller is highly experienced with 2465 repair and recommends against installing a heat sink on the U800 IC.

author: tkamiya
author_rank: Super Contributor
timestamp: October 28, 2018, 10:55:24 pm
content: Probably no less than two dozen scopes of 70s and 80s vintage went through my lab during last and this year. I have yet to see one which CRT is just worn out tired. If it's nice and bright and sharp in focus, and you paid reasonable price for it, I wouldn't worry about it. Do you see any burn in on your CRT? That's usually a pretty good indicator of neglect.

author: David Hess
author_rank: Super Contributor
timestamp: October 31, 2018, 05:39:12 pm
content: I also have yet to find a Tektronix oscilloscope of that age or older with a confirmed worn out CRT except for early 2213/2215s which operated the CRT heater at too high a voltage.The 2465 series oscilloscopes I have used however had a "softer" display than their slower contemporaries and this shows up in videos and photographs as well. I suspect this was a result of their CRT design which relies on greater scan expansion for higher bandwidth with a shorter CRT at lower deflection voltages.Quote from: NHnewbie on October 27, 2018, 04:40:32 pmThat is my recommendation also. I think the problem with U800 was improper mounting which caused excessive stress on the lead frame and die attachment.

author: NHnewbie
author_rank: Contributor
timestamp: November 01, 2018, 07:35:30 pm
content: Thanks to those who responded. The CRT will likely outlast me!RickK8EZB

author: 0culus
author_rank: Super Contributor
timestamp: November 02, 2018, 05:28:03 am
content: Quote from: David Hess on October 31, 2018, 05:39:12 pmI've found that if you're working under 20 MHz, the bandwidth limit feature massively sharpens the traces.OP, I recently got my 2465B refurbished from a reputable seller on ebay and it's CRT looks to be in great shape. You'll have to let me know how you like the options. I was thinking of perhaps being on the lookout for a second one with a few options (mine is a bare bones 2465B).

author: NHnewbie
author_rank: Contributor
timestamp: November 02, 2018, 02:06:20 pm
content: QuoteOnly a little time with this scope so far but here are initial impressions re options:Option 09 (CTT and WMR)/ Option 1E (CTT with EFR):Counter/Timer/Trigger, Word Recognizer and External Frequency Reference: Overall, this seems quite useful; the external freq ref (Option 1E) probably not relevant for most users, but does add another digit of resolution (8 vs 7 digits) to freq measurements.Options 10 (GPIB); havent tried this and suspect useful to a small minority of users.My scope does not have Option 05/5H (TV & HDTV), or Option 01 (DMM). I suspect the TV options will not be relevant to most present day users. As for the DMM, may be useful if scope is used mostly as a portable, but for bench use, a separate DMM would be my preference.RB

author: tkamiya
author_rank: Super Contributor
timestamp: November 02, 2018, 04:07:56 pm
content: If anyone needs spare parts, do let me know! I have Tek2465BCT where counter module is defective. I don't mind parting it out.

author: 0culus
author_rank: Super Contributor
timestamp: November 02, 2018, 04:33:34 pm
content: Quote from: NHnewbie on November 02, 2018, 02:06:20 pmYeah I doubt I'd need the DMM or the TV stuff, but the CTT option seems like it could be nice to have. I think mine actually does have the external frequency reference, now that I think about it. Thanks!Quote from: tkamiya on November 02, 2018, 04:07:56 pmWill definitely keep that in mind!

author: NHnewbie
author_rank: Contributor
timestamp: November 02, 2018, 04:35:10 pm
content: QuotePossible interest in some of the boards if a late instrument serial no. (B050000 and higher) and boards are working.RB

author: David Hess
author_rank: Super Contributor
timestamp: November 06, 2018, 08:59:05 am
content: Quote from: 0culus on November 02, 2018, 05:28:03 amThis is *with* the 20MHz bandwidth limit engaged and I hardly see any difference in noise with or without the 20MHz bandwidth limit on my 150MHz 2445B.QuoteMy 2445B has video triggering but that is hardly useful these days.I think the counter/timer option would be the most useful but I have not used it myself. The contemporary 2247A has more useful automatic measurement capability since it operates continuously.

author: med6753
author_rank: Super Contributor
timestamp: November 06, 2018, 10:18:22 am
content: Quote from: David Hess on November 06, 2018, 08:59:05 amThere is a noticeable difference in trace noise on the 2465's because of the much higher bandwidth.Quote from: David Hess on October 31, 2018, 05:39:12 pmIt is very useful.