atkelar | Workshop Project #9: CRT Tester (BMR 90) @atkelar | Uploaded July 2021 | Updated October 2024, 19 hours ago.
There are fewer and fewer CRTs out there every day. Most parts are commonly available, like transistors and even some microchips, but the CRT itself... not so much anymore. Wikipedia mentions that some industries still need CRTs, but replacements for consumer TVs are next to nonexisting.
In order to gear up for the occasional patient that might come through my little workshop, I decided to invest into a CRT tester. This one also includes a rejuvinator, or regenerator. It was made by a German company that went under in the 2000s and now all that remains is a PDF with the CRT tester adapter catalog on their website, which is now a front for a charity that advocates for organ donor cards. Weird combo.
The device had a few broken switches which required a creative solution, and the anode connector was missing. But since that involved only slapping a 4mm banana plug on a NOS plug I found on e-bay, I didn't include that in the video.
Since there are no new adapters available, I decided to sacrifice one of the provided ones for the socket and convert a few test leads into a "universal" adapter. Nothing for the faint of heart, since at least one lead carries the full 600-odd Volts for the G2 pin. Better stand clear when in use! Especially since the mains voltage is directly connected to - again - some of the output pins in some of the modes, depending on the switches. This is definitely NOT a toy! Especially with the high voltage pin on a regular, non-shielded 4mm banana plug...
I pushed this one through to test a non-working TV I have on my bench now. Given the symptoms, one possible failure would have been the CRT... and I wanted to rule that out early to focus on a solution or stop wasting time with the TV. I am glat to report that the TV is in basic working condition again and as soon as I get around to do the adjustments, it will be another video of course!
I couldn't resist to write out one of the warranty cards that came inside the case: the manufacturer - Müter GmbH - has included a set to validate that a TV has been processed properly. Also, sorry for the post-credit joke... reading the manual about how the rejuvination part works felt a bit like reading a fairy tale to me, so I just had to... ;)
0:00 Intro
1:25 The Button Problem / Opening up / High vs. Low Effort
2:35 Removing Mode Switches / Repairing Indicator Caps
3:32 Floating Resistor / Capacitors
5:22 Mode Buttons, Spring Problem / Reassembly
6:30 Cleaning Bulbs / Testing Potentiometers
7:12 Cleaning Case / Closing Unit
7:54 Adapter Cable Plug
8:41 "Universal" Adapter
9:52 Theory of Operation / Short Test and "Fix" / Current Measurements
11:30 Rejuvination Description / First Test
12:55 Completed! / Credits / Bonus
Wikipedia on CRTs: en.wikipedia.org/wiki/Cathode-ray_tube
Radiomuseum on the Device: radiomuseum.org/r/muter_bildroehren_mess_regener_2.html
Music:
My Train's A Comin'
Unicorn Heads
(YouTube Audio Library)
You can support me on Ko-Fi: ko-fi.com/atkelar
There are fewer and fewer CRTs out there every day. Most parts are commonly available, like transistors and even some microchips, but the CRT itself... not so much anymore. Wikipedia mentions that some industries still need CRTs, but replacements for consumer TVs are next to nonexisting.
In order to gear up for the occasional patient that might come through my little workshop, I decided to invest into a CRT tester. This one also includes a rejuvinator, or regenerator. It was made by a German company that went under in the 2000s and now all that remains is a PDF with the CRT tester adapter catalog on their website, which is now a front for a charity that advocates for organ donor cards. Weird combo.
The device had a few broken switches which required a creative solution, and the anode connector was missing. But since that involved only slapping a 4mm banana plug on a NOS plug I found on e-bay, I didn't include that in the video.
Since there are no new adapters available, I decided to sacrifice one of the provided ones for the socket and convert a few test leads into a "universal" adapter. Nothing for the faint of heart, since at least one lead carries the full 600-odd Volts for the G2 pin. Better stand clear when in use! Especially since the mains voltage is directly connected to - again - some of the output pins in some of the modes, depending on the switches. This is definitely NOT a toy! Especially with the high voltage pin on a regular, non-shielded 4mm banana plug...
I pushed this one through to test a non-working TV I have on my bench now. Given the symptoms, one possible failure would have been the CRT... and I wanted to rule that out early to focus on a solution or stop wasting time with the TV. I am glat to report that the TV is in basic working condition again and as soon as I get around to do the adjustments, it will be another video of course!
I couldn't resist to write out one of the warranty cards that came inside the case: the manufacturer - Müter GmbH - has included a set to validate that a TV has been processed properly. Also, sorry for the post-credit joke... reading the manual about how the rejuvination part works felt a bit like reading a fairy tale to me, so I just had to... ;)
0:00 Intro
1:25 The Button Problem / Opening up / High vs. Low Effort
2:35 Removing Mode Switches / Repairing Indicator Caps
3:32 Floating Resistor / Capacitors
5:22 Mode Buttons, Spring Problem / Reassembly
6:30 Cleaning Bulbs / Testing Potentiometers
7:12 Cleaning Case / Closing Unit
7:54 Adapter Cable Plug
8:41 "Universal" Adapter
9:52 Theory of Operation / Short Test and "Fix" / Current Measurements
11:30 Rejuvination Description / First Test
12:55 Completed! / Credits / Bonus
Wikipedia on CRTs: en.wikipedia.org/wiki/Cathode-ray_tube
Radiomuseum on the Device: radiomuseum.org/r/muter_bildroehren_mess_regener_2.html
Music:
My Train's A Comin'
Unicorn Heads
(YouTube Audio Library)
You can support me on Ko-Fi: ko-fi.com/atkelar
