Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Diagnostic & Test Equipment

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #1  
Old 05-06-2012, 11:38 AM
andy's Avatar
andy andy is offline
VideoKarma Member
 
Join Date: Jul 2002
Location: Austin, TX
Posts: 3,987
WTB Tektronix 564

I'm feeling nostalgic for a classic Tek scope, and the 564 looks like the best option. It's small enough not to be in the way, and modern enough to use occasionally. I also have a nice 3B3 dual time base that will fit it. Before I spend more than its worth on ebay, does anyone have one they want to part with? I'm located in Austin, TX for shipping.
Reply With Quote
  #2  
Old 05-06-2012, 01:48 PM
jr_tech's Avatar
jr_tech jr_tech is offline
VideoKarma Member
 
Join Date: Sep 2009
Posts: 3,786
In "Oscilloscopes Selecting and Restoring a Classic" (1992) by Stan Griffiths, W7NI, the 564 is not recommended due to the short life span of the special "storage" CRT:

Quote:
Buy a storage oscilloscope only if you really need the storage feature. They cost more to maintain and replacement cathode ray tubes can be impossible to find
The same book shows the 561A, which is the same size and takes the same plug-ins:

Quote:
the 561A is a good general purpose mainframe. You will need two plug-ins to make it a complete oscilloscope.
Of course, you could get lucky and find a 564 with a good tube.

jr
Reply With Quote
  #3  
Old 05-06-2012, 02:31 PM
andy's Avatar
andy andy is offline
VideoKarma Member
 
Join Date: Jul 2002
Location: Austin, TX
Posts: 3,987
Thanks for the warning. I wonder what happens to the CRTs? Is it general low emission, or a problem with the storage feature? There are several NOS 564 CRTs on ebay right now (although for more than a complete 564 is worth).

I had a 564 about 8 years ago, but it had to go when I moved across the country. There was an intermittent problem with the power supply that caused the -100v supply to lose regulation that I never finished tracking down, but it had a good CRT as far as I could tell.

I agree that mesh storage isn't a very useful feature anymore, but if I'm going to make room for a vintage scope, I might as well get one with everything.
Reply With Quote
  #4  
Old 05-06-2012, 03:09 PM
jr_tech's Avatar
jr_tech jr_tech is offline
VideoKarma Member
 
Join Date: Sep 2009
Posts: 3,786
Quote:
Originally Posted by andy View Post
I agree that mesh storage isn't a very useful feature anymore, but if I'm going to make room for a vintage scope, I might as well get one with everything.
The 564 is not a mesh storage scope... the storage takes place on the P-1 phosphor surface itself, and the stored information is "illuminated" by low voltage electrons. In order to get usable brightness of the stored traces, at these low voltages, a fairly high current density is used. This will cause "aging" (loss of efficiency) of the phosphor areas most used for storage of traces.
This is similar to the aging observed in a 6E5 indicator "eye" for many of the same reasons... P-1 phosphor bombarded with high current (low voltage) electrons yields loss of phosphor efficiency in the most used areas. I have seen several used 564s with ugly dark areas/traces "burned" into the phosphor, seen in "store" mode...."non-store" operation is usually not degraded by these "burned" areas.

IMHO, the 564 is a lot more fun than a 561... if you get one with a good CRT, and don't use the storage function too much, it can last for many years.

jr
Reply With Quote
Reply


Thread Tools
Display Modes

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

Forum Jump


All times are GMT -5. The time now is 09:12 AM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
ęCopyright 2012 VideoKarma.org, All rights reserved.