The electron beam of old analog oscilloscope TYPE TR-4657 not showing - Page 1
Forum section: electronics / testgear

author: pancake9590
author_rank: Newbie
timestamp: May 21, 2019, 10:41:40 am
content: Hello everyone, I got this oscilloscope from my university, when they were changing the old ones with new digital oscilloscopes.And so, to not be thrown on the garbage I thought that as electronic hobbyist it will be good for me too. The guy that gifted the oscilloscope to me tested it in front of me and when he was testing it everything was working fine.He mentioned that I will only have to clean it up from inside from the dust and it will be ready to go. So I returned happy at home with my new old analog oscilloscope.Forgot about it for about an year.And when I turned it on lately the electron beam on the monitor was not showing at all, I could not find any dot at first place to form a beam.So here I am, asking for help. What it can be? It was not touched for an year and it worked when the guy showed it to me. Could it be me, not finding the dot, because I am new to this type of oscilloscopes?I have searched for a button that shows the dot on the center of the display in order to know to start bringing the dot up or down, but did not found such button on my oscilloscope.Can I make some diagnostic to find the problem (if there is one) ? Please help me, it is a good oscilloscope, two channel and I want to start using it.

author: YetAnotherTechie
author_rank: Regular Contributor
timestamp: May 21, 2019, 12:17:32 pm
content: In the radiomuseum website there is a picture at an angle that clearly shows the push buttons and beams on. Set all rotary buttons to mid position, intensities to 3/4 and the push buttons as in the picture. Post results.https://www.radiomuseum.org/r/elektronik_dual_beam_oscilloscope_15_3.html

author: pancake9590
author_rank: Newbie
timestamp: May 24, 2019, 05:01:02 pm
content: Sorry for the late reply, but could not get my hands on it the day after your response. So here it is now, I tried to copy all push buttons like in the picture from the museum, but I am not really sure about it because you can not have bigger size of the picture if you are not a member of the museum. So I tried to make it up as close as possible to your description, but still no result. Here are the pictures after the changes. Can you look and tell if I have made any mistake with the push buttons or something? Thank you for your help by the way!P.S. Tried taking the pictures at an angle, so you could see and compare the museum picture and the ones I made.(hope they are good enough)

author: YetAnotherTechie
author_rank: Regular Contributor
timestamp: May 27, 2019, 10:35:35 pm
content: Hello,I don't know your specific oscilloscope. It might help if you could take pictures that show the push button labels only.In any case, this is a dual beam scope, so it's like having two independent scopes, one on the left, one on the right.You can focus your efforts on one of the sides plus a push button combination.

author: LazyJack
author_rank: Frequent Contributor
timestamp: May 28, 2019, 07:24:28 pm
content: Find the link to the manual on this page.http://regimuszereklhanzi.5mp.eu/web.php?a=regimuszereklhanzi&o=Rpm1so_VpyThis is a Hungarian made scope.

author: LazyJack
author_rank: Frequent Contributor
timestamp: May 28, 2019, 07:25:50 pm
content: A common problem is arcing at the HV transformer or rectifier.