tektronix 2213 cant view both trace - Page 1
Forum section: electronics / repair

author: topology
author_rank: Newbie
timestamp: July 02, 2015, 02:20:57 am
content: hi allrecently i bougth a tektronix 2213 scopewhen i test it .......it can trace CH1 then i switch to CH2 and it trace that to niceBUT ,WHEN I SELECT BOTH IT ONLY SHOW ONLY ONE TRACEthis problem only on CHOP , ALT in VERTICAL MODE & INTENSE MODE>THIS SCOPE CANT VIEW 2 TRACE<i have downloaded the service manual but i don't know where to start

author: Addicted2AnalogTek
author_rank: Frequent Contributor
timestamp: July 02, 2015, 01:32:30 pm
content: did you hit beam find while you were attempting to view 2 traces to see if it's actually there but just not visible?

author: topology
author_rank: Newbie
timestamp: July 02, 2015, 02:47:09 pm
content: yes i did nothing just one trace

author: Addicted2AnalogTek
author_rank: Frequent Contributor
timestamp: July 02, 2015, 05:06:37 pm
content: I'm fairly new to all of this myself, but what I would do is try to isolate what area the problem is in.Possibilities:-Able to view both channels separately but not together =1 - Chop/Alt clock not properly functioning?2 - 2nd trace sweep not being triggered when Chop/alt clock active?etc.it sounds like you've probably done this already, but mess with every last setting and try every possible combination of settings and list what ones are not working correctly, and then compare and find what section all of these issues have in common.My personal first guess is the chop/alt clock. download the manual and start checking voltages and waveforms.

author: topology
author_rank: Newbie
timestamp: July 03, 2015, 04:13:52 pm
content: this is what i found

author: Addicted2AnalogTek
author_rank: Frequent Contributor
timestamp: July 03, 2015, 04:35:11 pm
content: bingo. I've noticed that even though my Tek 465 works properly, the chop clock seems to have some leakage issues. The 468 I'm repairing also had chop clock issues. I will download the manual and take a look to see if I can aid further.In the meantime, I suggest you start on the vertical mode switch board testing the voltages (or as close as you can get to that point - such as the pins of the connector that goes into the vertical switching logic). I'm guessing that the manual is one which does have voltages specified in the schematics, and the settings in which you should have the scope in order to get proper readings.Are all 3 (CH1 enable, CH2 enable, and Chop Clock) stuck at the same voltage? do they change at all when you cycle those vertical mode selector switches, or do they just stay constant?I'll have a look at the manual soon and get back with some more ideas.

author: topology
author_rank: Newbie
timestamp: July 03, 2015, 08:31:23 pm
content: yes they changed and i need to do more test

author: Psi
author_rank: Super Contributor
timestamp: July 03, 2015, 08:44:04 pm
content: I don't know this scope but have you checked you don't have math functions on A+B etcNever mind, I see you have found bad signals on the board

author: Addicted2AnalogTek
author_rank: Frequent Contributor
timestamp: July 03, 2015, 09:22:48 pm
content: Even though this isn't going to have anything to do with your problem, go ahead and check your power supply voltages, waveforms, and ripple on the regulated side and make sure that they are within spec. If they aren't, they could easily affect any of the waveforms/voltages you measure throughout this troubleshooting and make you think that you may have issues where you really do not.After that, check the waveforms from the picture below and see if you find anything off. If you don't, then the culprit will likely be U310A (on diagram 3). However I think you will find some bad waveforms in the sweep logic (diagram 5). maybe a fried VR644 (check voltage across it), a cracked resistor, or bad cap, or it could be something else.

author: topology
author_rank: Newbie
timestamp: July 04, 2015, 02:54:59 am
content: u know what the manual i have downloaded schematic 3 is missingon other hand U317 PIN 3 which have the missing clock signal is connected only to U301 PIN 3ONLY?!!!! the datasheet just say CLK1 .......if i fined those IC's tommorro i am going to replace them

author: Addicted2AnalogTek
author_rank: Frequent Contributor
timestamp: July 04, 2015, 09:42:25 pm
content: http://ko4bb.com/manuals/index.phpdownload the 2nd one.I noticed that diagram 3 was missing from the ElektroTanya manual also.It can't hurt to replace those IC's, but it might not solve your problem. The origin of your problem could be further back in the circuit. If swapping those out doesn't solve it, I think you might find your answer in the diagram that I posted.

author: topology
author_rank: Newbie
timestamp: July 05, 2015, 12:46:52 am
content: thank you for this manuali swap those IC's ..... no effect on targeti think i need to deeper

author: Addicted2AnalogTek
author_rank: Frequent Contributor
timestamp: July 05, 2015, 01:35:22 am
content: I had a feeling that swapping those wouldn't do anything. I very recently began going thru my first real scope troubleshooting and repair, and have learned loads since. I've probably spent a couple hundred dollars on various parts (in quantity) before I figured out how to trace and identify the actual problem parts.I wouldn't suggest replacing anything else unless you know that it's definitely bad. Either that, or because you're left with no other choices other than process of elimination type tactics.

author: topology
author_rank: Newbie
timestamp: July 06, 2015, 04:09:07 am
content: that's all u can do with no schematicsi agree with you but i do not have time for my scope wright nowand those ic's i have them for around 3$ thank you for the schematic again