Cathode.ray tubes for tektronix - Page 1
Forum section: electronics / testgear

author: Analogdevice
author_rank: Contributor
timestamp: March 01, 2014, 01:50:02 pm
content: Hello gentlemen.Let me introduce myself. My name is Lubomír, I´m 19 and I living in a small country called Slovakia. (Note: not slovenia, like tekfan). My hobbies are servicing analog (and sometimes digital) measure equipments for electronics, such as oscilloscopes, counters, generators, all kinds of meters, etc.Today I have the tektronix 7613 oscilloscopes on my table. It´s fully operational machine, but I want change CRT in 7613 from Tek 466, because I like the graticule on CRT from 466. Do you have datasheets from both of CRT´s? Or could you tell me, if this CRT´s are compatible.Thank you very much for response.Best regardsLubomír Tomík, Slovakia.P.S.: sorry for my english, I´m still learn it.

author: PaulAm
author_rank: Frequent Contributor
timestamp: March 01, 2014, 02:00:48 pm
content: Maybe this will helphttp://www.reprise.com/host/tektronix/reference/crt.aspAlso, sphere has some CRT specs:http://www.sphere.bc.ca/test/crt-data.html

author: Analogdevice
author_rank: Contributor
timestamp: March 01, 2014, 10:54:51 pm
content: Thanks for your response.On the sphere.com they don´t have the datasheet of this one

author: Analogdevice
author_rank: Contributor
timestamp: March 02, 2014, 09:38:32 am
content: So I was looked at schematics from 7613 and 466. Looks like CRT´s are pin compatible. But somewhere is different voltages, for example the astig. gate variable resistor is connected to +130V on the 7613 and to +140V on the 466. I think that the CRT´s are compatible, but after change I will must adjust screen geometry like trace rotation, astigmatism, focus etc.What do you think?

author: Rigby
author_rank: Super Contributor
timestamp: March 03, 2014, 01:05:18 am
content: If the voltages are that close, I think you'll probably be OK. You might not get the full range on the astigmatism adjustment, to use your example, but you should be able to get there.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: March 03, 2014, 01:35:01 am
content: Hi,I do not believe that these CRTs are compatible.The 466 has a much higher writing speed at 1350cm/us (full scan mode)compared to the 7613 which is only 5 div/usThe writing speed is a measure of how fast a single event can be captured on the screen.Jay_Diddy_B

author: Rigby
author_rank: Super Contributor
timestamp: March 03, 2014, 01:47:24 am
content: Right, but he wants to put the higher performance tube in the lower performance body. He's not asking a 7613 tube to perform as a 466 tube would in a 466.

author: crusader66
author_rank: Contributor
timestamp: March 03, 2014, 02:58:35 am
content: Hello Lubomír,I am curious if the CRT in the 7613 happens to be the Option 6 CRT. When the 7613 was sold with a 7L13 spectrum analyzer module installed, Option 6 "replaces the standard crt with one incorporating a special internal graticule for Spectrum Analyzer operation." The option 6 crt has a 8 x 10 division display area with LIN, LOG, and Frequency markings.Because you didn't mention the crt being drastically different from the 466 I doubt that is what you have but I thought I would point this out before you removed it.(I am fairly certain there were more model numbers for the SA module. I used the 7L13 as an example as it is the one that I have in my 7613.)

author: Analogdevice
author_rank: Contributor
timestamp: March 03, 2014, 01:23:36 pm
content: Hello.Thank you for fast response. I was tested the 7613 and the CRT is lightly burned. 7613 was sold with option3, now there are 2pcs. 7A18 for vertical channels and 7B53A for horizontal channel. But if I know, the crt from 466 had a auxiliary anode for reduced scan (pin6), when the catode was turned into -3kV from -1,5kV.So I think that solution is connect this auxiliary anode to pin 13. What do you think?I know, that it´s absurd, change the CRT only for graticule, but I have 2pcs. of 466 CRT´s in new condition.Quote from: Jay_Diddy_B on March 03, 2014, 01:35:01 amJay, you are right. But I know, that I can´t change the parameters, I wanna change only CRT.

author: iDevice
author_rank: Regular Contributor
timestamp: March 03, 2014, 08:13:38 pm
content: Quote from: Analogdevice on March 03, 2014, 01:23:36 pmThat's interesting !Any chance to buy you one of these 466 CRT's ?I have a fully restored 466 just laying on my shelf, waiting for a matching donor as my copy is on the weak side as far as beam intensity is concerned.

author: Analogdevice
author_rank: Contributor
timestamp: March 03, 2014, 10:33:56 pm
content: I envy you the 466. I had tesla BM621 - the czechoslovakian clone of 466 with this CRT, but:1. the weight is so high relative to 466 tek,2. the dimensions is too large and...3. the VN transformer burned and I can´t wind with 0,1mm wire, I don´t have machine to do it. And I don´t want to repair it, beacuse it is only tesla, the format is poor. There are used plastics of poor quality, faulty power supply etc. So I bought tek 463 because of it.Moreover I have 463, 7613 now and digitizing HP54503A. I bought 7613 for 94€ from germany, but I want change it by 466 or something tektronix, where was used this CRT with this great graticule. I´m still looking on e-bay if there are auction or 466 for sale.Please, contact me by mail: ltelektronr@gmail.com.

author: iDevice
author_rank: Regular Contributor
timestamp: March 05, 2014, 10:36:23 pm
content: You can find 466's on eBay.But these models are clearly not as popular as the 465, there were specialty models back in the days and used for specific purposes.The fact that the special CRT made them quite expansive and the lack of luminosity to protect the storage meshes made them not as universal as their 465 sibling.You have to use them with special care to preserve the life of the CRT.Also the usable screen area is smaller and the graticule is cluttered by the reduced scan area in the middle.And finally the screen and graticule are almost unreadable due to the heavily smoked front mask.I wonder why you find this graticule so great btw...It becomes better after LED conversion though because you can boost illumination beyond what the original bulbs were capable of. But that won't help a fading CRT though.But, all these limitations and particularities are what distinguish them from the mass and why I find them so desirable as vintage instruments.It's a wonderful piece of old technology. The complexity of the storage system and preparation sequences is amazing and it takes a while reading the service manual to understand the principle of operation. Respect to the engineers who designed these CRT's and driving electronics.And they are so much fun to restore because you can spend hours just to disassemble them ;-)No one would build instruments like that today for sure !I'll contact you by PM next w-e.

author: David Hess
author_rank: Super Contributor
timestamp: March 05, 2014, 11:16:06 pm
content: Quote from: iDevice on March 05, 2014, 10:36:23 pmI used a 468 long ago and was never impressed by it but I have a 7834 that works great that I make good use of. It is still noticeably dimmer than its non-storage counterparts though. Where it really shines is catching elusive glitches by displaying 500,000+ sweeps per second which is faster than current DSOs until you get into the $3000+ range.Storage CRTs use a significantly lower post deflection acceleration voltage, like half, than their non-storage counterparts making them dimmer. Reduced scan mode can make up for some of this but it sacrifices deflection sensitivity.

author: Rigby
author_rank: Super Contributor
timestamp: March 05, 2014, 11:39:24 pm
content: Yeah, I'm kind of amazed by what my Tek 7633 can show me. the analog storage tube is kind of a neat thing, too. not practical in a lot of ways that DSOs are practical, but very neat nonetheless.

author: David Hess
author_rank: Super Contributor
timestamp: March 06, 2014, 04:08:39 am
content: The 7834 I have was my first exposure an analog storage oscilloscope since the 464 that I was so disappointed with long before but it is an entirely different class of instrument. It only looks dim compared to its cousins which have post deflection acceleration voltages about 2.5 times higher and when I first got it, I was surprised how bright it is but they make it look dim. I only use it for glitch hunting when my fastest DSO which is pretty slow is not fast enough.At some point I plan on picking up a 7613, 7623, or 7633 for less demanding applications.