European Tektronix 2465B - Help - Page 1
Forum section: electronics / beginners

author: Firebird00
author_rank: Contributor
timestamp: March 02, 2017, 01:00:30 am
content: Hi all.Just arrived here and it's my first post, hope somebody can help me. Please sorry for my bad english, be sure I will do the best of me to you understand what I mean. Thank you.I bought today an 2465B, european versión with serial number H705186. As service manual states, this one was made in The Netherlands, or at least assembled there. I don't think Tektronix was building this scopes in Europe, but maybe assembled, what do you think? The case is that this unit now resides in Spain, and will be here for long time.If this scope supports one summer here in the south of Spain then be sure that this is like a rockI bought this unit in EBay, and arrived at my home today. The scope was showing in the picture on EBay an error, "Test 02 Fail 53". Looking at the SM I found that the problem was the Delta T key, and then I told myself "go for it". Received it today and after a fast looking I saw that this key was stucked pressed, so pull out the key with small pliers and "Bingo" now the key Works and feel correct.Power on the scope again and the key error was dissapeared, but another error comes, Test 04 Error 11. The SM shows calibration problem. After Reading a lot in this forum I've downloaded the NVRAM file, and I will try to burn a new DS1225 that I will buy in Mouser, don't know if that will work, but I will try... Don't know what will happens because this unit comes with Option 05 (TV), and maybe I will get some errors coming from that option..?Another issue with this scope is that after about 20 seconds working (when cold) the trace starts to dissapear together with readout and in less tan 5 seconds there is no image on the screen, and did not come again when power off/on several times. If wait some hours then I see the trace/readout again for some seconds and dissapears again, slowly (5 seconds...).The rest of the scope seems to work fine, if I press A/B Trigger key to sort the Cal error, pressing the keys it changes the parameters, channels, trigger, coupling, Autoset can hear the noise of the relays working, etc, all keys are working but no image on the screen. For this reason I think I can discard any issue with logic boards, but concentrate my attention to HV supply to CRT.I know that is a good idea to change all Electrolytic capacitors, and I will do it soon, when I see that the scope is working. For Now I want to see the trace and do some tests.I will open the scope this week and I will take pictures that I will post here. Maybe someone find this unit interesting by the fact that is rare to find (at least in this blog I think). I want to open it not only to repair it, but to see if there are big differences between the US Spec and this one, will see soon.Can you please point me in the right direction on what to look first to solve the screen problem? I'm not an expert in electronic things, but very basic knowledgment.Thank you all in advance.

author: rstofer
author_rank: Super Contributor
timestamp: March 02, 2017, 01:09:48 am
content: All I can do is point out that there are several Tektronix specific repair/refurbish forums via Google.One such forum:https://forum.tek.com/

author: tggzzz
author_rank: Super Contributor
timestamp: March 02, 2017, 09:18:41 am
content: Quote from: Firebird00 on March 02, 2017, 01:00:30 amThe NVRAM contains information that is specific toyourscope, especially the software calibration constants. Information that is common to all scopes is stored in ROM, not NVRAM.You should definitely try to read the NVRAM's contents and store them somewhere safe. The easiest method is via the test routine that single-steps through the contents; if possible I would take a video of the screen while scrolling through the contents, since that is fastest and you can interpret any characters at your leisure.QuoteYour first step is to check the various low voltage PSU rails.Your second step is to look at the control DAC output voltages.Your third step is to investigate the Z output waveform.Your fourth step is tovery carefullyinvestigate the high voltage PSU and DC restorer circuits.There is much good information about those on this forum and in the Yahoo TekScopes group.QuoteChanging anything risks damaging the equipment, so don't do it unnecessarily.I would expect that you would have to change the infamous mains EMI film capacitors before they detonate. There's a good pdf on the forum, IIRC from condoraudioYou will probably have to change some capacitors on the control board near the DAC. Again, this is well described elsewhere.

author: Firebird00
author_rank: Contributor
timestamp: March 02, 2017, 07:44:18 pm
content: Ok, I can try to read the contents of the NVRAM but do you think it will be posible when the scope says Test 04 Fail 11 on startup?I'm asking that because I was thinking the calibration data are lost in this point...One thing I miss to say is that when I can see the trace/readout, the bottom line shows a lot of questions, together with some readable data. Also, today the image on the scope was there for about 2 minutes!!, yesterday 20 seconds. Maybe if I don't do anything and start it every day, after 1 year I will get half an hour of imageOk, this weekend I will open it, take pictures and show what it's inside, and will take the measures as the SM says.Regarding the CRT problem, don't you think the responsible of that issue is a bad capacitor on the HVPS?Yoy say "Changing anything risks damaging the equipment, so don't do it unnecessarily."AMENI'm totally with you, and that's why I'm focusing my attention to the CRT only. Once solved I will do the next step, that is the calibration issue if the image on the CRT is stable.Ok I've downloaded all the valuable information you said. I will need that info in the near future...Thanks a lot