Firts scope, Tektronix 465 repair and restoration - Page 1
Forum section: electronics / repair

author: v1t0r
author_rank: Contributor
timestamp: July 09, 2013, 03:07:18 pm
content: I'm new to the forum, but for quite some time that i follow the EEVBlog.Recently managed to get my hands on an old Tektronix 465 which has some problems, on CH1 volts\div from 0.5V to 50V range does not show the waveform, CH2 shows the waveform very blurred and curling.Already disassembled the scope, I noticed that the selector volts\div is controlled by cam-and-leaf contacts I will try to remove the board and clean the contacts to see if the problem in CH1 disappears. For CH2 does not have the slightest idea what might be causing the problem.Added a video to demonstrate the problem on CH2, if someone can help me locate the cause of the problem would be very grateful.I appreciate all the help given, and I apologize for my poor english.[img=http://s16.postimg.org/r6s593oa9/IMG_20130708_173714.jpg][img=http://s16.postimg.org/lbbzqxd4h/IMG_20130708_173919.jpg]http://youtu.be/ot2I6EbVKBQ

author: w2aew
author_rank: Super Contributor
timestamp: July 09, 2013, 03:22:38 pm
content: The best way to clean those leave contacts is to soak a strip of paper in isopropyl alcohol and rub it between the contacts and the lands on the board.You might want to check out this excellent thread on the restoration of a 465:https://www.eevblog.com/forum/projects/tektronix-465-repair-and-restoration/The wiggly trace looks to me like power supply ripple. You're going to want to go through and check the caps in all the power supplies.

author: v1t0r
author_rank: Contributor
timestamp: July 24, 2013, 06:09:39 pm
content: What appeared to be an easy problem to solve eventually became a pretty hard to solve, after opening the oscilloscope and take a look at the contacts of CH1, I checked that was all right with them. The problem appear after several hours around components of CH1.A google search revealed that this component is an attenuator, and for my frustration is not a common part to find. Already looked on ebay and did not find the exact part.Anyone know where I can find this part.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: July 25, 2013, 03:57:50 am
content: Just fix the part. Carefully open it up using an exacto knife to break the glue joints.The solder joints are likely cracked. This was a super-common problem due to the strange silver bearing solder used in the pins. I have to admit on my 465 I just used a bit of 60-40 to fix them. If you google around, I'm sure you'll find the "correct" solution.I learned about this on the damn Yahoo group. Why can't they make those more useful? I guess Yahoo just likes wasting resources.

author: v1t0r
author_rank: Contributor
timestamp: July 25, 2013, 01:40:18 pm
content: hi Paul Moir, thanks for replying.I did what you said, I applied some solder on the joints but unfortunately not solved the problem.

author: ptricks
author_rank: Frequent Contributor
timestamp: July 25, 2013, 01:56:01 pm
content: They have quite a few Tek parts, if it isn't listed call them because they may still have it or can get it.http://www.smcelectronics.com/tekpart.htm

author: Paul Moir
author_rank: Frequent Contributor
timestamp: July 26, 2013, 01:47:07 am
content: Ah, darn.Sphere has 'em:http://www.sphere.bc.ca/test/tek-parts/tekpots.html$14.They have grab bags too!

author: Computeruser
author_rank: Regular Contributor
timestamp: July 26, 2013, 02:01:28 am
content: There are a couple of approaches (I have used both).1. Find a better 465 on eBay (one known to be working and to be returnable). Use your problem 465 as a source of spare parts.2. Find a 465 junk machine on eBay as cheap as possible. Use it as a source of parts for your problem machine. I purchased a 7704a junk box for next to nothing which I stripped down and use special TEK parts to repair a good working 7704a..... C