Tektronix TDS 544A CRT Repair

**Donny3000** · 1st April 2009 02:00 PM

Re-posting in this forum since it's more applicable.

Hello Everyone,

I have acquired a Tek TDS544A Oscilloscope that had a faulty CRT that needed replacing. I was able to find a replacement CRT from Clinton electronics, but I noticed that the original CRT screen has another screen in front of it, which has some additional wiring coming off of it. This additional screen seems to be attached to the CRT with some kind of black rubber-like compound. I believe this screen is to display the soft menu items of the system. I was wondering if anyone has had to replace such a CRT display for these scopes and, if so, how they went about modifying the new display to work with the o'scope. Any help or information would be greatly appreciated.

Thanks,
Donald

**Sceadwian** · 1st April 2009 04:48 PM

Sounds like you should just be able to carefully cut the seal from the secondary screen away from the main CRT, as close to the CRT glass as you can. But I could be wrong there. Can you post some decent pictures of this?

**Donny3000** · 1st April 2009 06:07 PM

Sure, I'll take some pictures this evening when I get home and put them up.

**Donny3000** · 3rd April 2009 02:13 AM

Sorry about the delay, but I couldn't find my digital carmera so I had to borrow one. But, carrying on, I have attached some pictures help clarify my previous illustration. Pictures 1-3 show different angles of the rubber black rubber-like compound that I am referring to (you can see on picture2 see were I started trying to remove it). You will also notice the rainbow colored ribbon cables coming from the sides that are attached to the glass laminate (which you can see in picure4.jpg) and are coming through the rubber-like compound. Picture4.jpg gives you a comparison between the old CRT (on the left) and the new one that I purchased. I'm apprehensive to just peel off the rubber compound without really knowing how it's actually attached. I did go to the Tektronix website and download the maintenance & repair manual, but it didn't go into detail about the actual CRT maintenance/repair. Just how to remove/replace it. Hopefully this helps a little, because it would really be nice to have a working screen for this scope. Thanks in advance.

**Sceadwian** · 3rd April 2009 10:15 PM

I'm not a tektronix expert here, and I'm not sure how much the scope means to you, but to me it looks like you should be able to pry it away from the tube, with a flat screwdriver or putty knife very carefully. Not sure what all is in between that thing though it looks like it's sealed pretty good. I'd get a second opinion but that's my inexpert opinion =) That overlay doesn't look like it's in very good shape though, is it required for the scope to function? I'm guessing it has the graduations on it or are there touch buttons on there too?

**Donny3000** · 4th April 2009 01:52 PM

Thanks for the reply. I'm indeed still looking around to see if I can find a little more information about how it's connected under the sealing, but right now I'm going to leave the prying of the seal/glass filter overlay as a last resort. To answer your questions, I'm not sure if the overlay is required for operation. I will test that scenario and post my results. I'm guessing that the overlay displays the graduations as well. I should be able to find that out from my eventual testing, but it doesn't contain the soft menu touch buttons. I had to remove the aluminum carbon contact frame that the touch buttons depress upon, as well as, the touch buttons (located in the aesthetic outer display frame) in order to reach the CRT. I will test to see if the scope powers up with the overlay connection removed.