DEC VT-101 Flyback Transformer Blues
Re: DEC VT-101 Flyback Transformer Blues
I have settled on the following snubber diode:
2CL2FM 20 kV 100ma 100ns
The 30 kV diodes I have been able to get a look at seem too large to fit. I think 20 kV should be fine given that the VT snubber is running at 15 kV when operating correctly.
The data sheet is attached here.
* this is not yet advice as I have yet to install and proof this diode
2CL2FM 20 kV 100ma 100ns
The 30 kV diodes I have been able to get a look at seem too large to fit. I think 20 kV should be fine given that the VT snubber is running at 15 kV when operating correctly.
The data sheet is attached here.
* this is not yet advice as I have yet to install and proof this diode
- Attachments
-
- D-2CL_Series_REV_5.0.pdf
- (262.58 KiB) Downloaded 3 times
Last edited by beatkamp on Fri Apr 26, 2024 12:26 am, edited 1 time in total.
Re: DEC VT-101 Flyback Transformer Blues
Ooof... scratch that.
I am getting:
2CL2FP 30 kV 100ma 100ns
- from the data sheet above.
I don't feel too cozy putting a diode in with so little safety margin: 15 kV operating with a 20 kV diode.
30 kV for 15 kV operating feels much better.
Now I wait for the part to arrive in Iceland.
I am getting:
2CL2FP 30 kV 100ma 100ns
- from the data sheet above.
I don't feel too cozy putting a diode in with so little safety margin: 15 kV operating with a 20 kV diode.
30 kV for 15 kV operating feels much better.
Now I wait for the part to arrive in Iceland.
Re: DEC VT-101 Flyback Transformer Blues
Wow. So.. This is the diode inside the flyback?
Re: DEC VT-101 Flyback Transformer Blues
I just received the diode and visually, its a perfect match. Now to install it. Very excited!
Re: DEC VT-101 Flyback Transformer Blues
Here it goes! I will insulate temporarily with electrical tape.
Re: DEC VT-101 Flyback Transformer Blues
OK,,this is exciting. Keep us (or me, ha) posted!
I have what I **think** is the exact same situation. But sadly, I am not the electronics expert you are, nor do I possess the equiptment you have for testing.
I have a few questions:
(A) Where did you get the diode from? Web link/url/info?
(B) If I shipped you MY flyback would you test it for me? To confirm my suspicions. I of course would pay all postage to and from and throw in a few bucks for your time.
If I have the same situation (after testing), I can do the same thing, I'm super good with my hands and have no problem soldering in a replacement component....
I have what I **think** is the exact same situation. But sadly, I am not the electronics expert you are, nor do I possess the equiptment you have for testing.
I have a few questions:
(A) Where did you get the diode from? Web link/url/info?
(B) If I shipped you MY flyback would you test it for me? To confirm my suspicions. I of course would pay all postage to and from and throw in a few bucks for your time.
If I have the same situation (after testing), I can do the same thing, I'm super good with my hands and have no problem soldering in a replacement component....
Re: DEC VT-101 Flyback Transformer Blues
So, I just tested and now I have a working flyback. Great. There is also bad news. Still, I have something not right here. The video board starts to heat up terribly and the video is not stable. I must still have a bad driver transistor. The video begins to fade out as quickly as the driver board heats up.
Re: DEC VT-101 Flyback Transformer Blues
The diode I had to get from Ebay. I paid 13 Euros for a single one. I am not in a position to recommend anyone do this as I have not been able to prove success.
Re: DEC VT-101 Flyback Transformer Blues
Another Test:
All video, CRT, driver board disconnected. Composite video only from the motherboard to a Sony monitor.
This works well.
So I have to have a look at what I am trying to accomplish here.
The goal:
- a fully functioning dummy terminal I can use daily
I am now going to look at fully replacing the CRT elements with a LCD panel.
Perhaps this is the best long term solution?
Its times like these I really miss the slide rule generation of engineers.
All video, CRT, driver board disconnected. Composite video only from the motherboard to a Sony monitor.
This works well.
So I have to have a look at what I am trying to accomplish here.
The goal:
- a fully functioning dummy terminal I can use daily
I am now going to look at fully replacing the CRT elements with a LCD panel.
Perhaps this is the best long term solution?
Its times like these I really miss the slide rule generation of engineers.
Re: DEC VT-101 Flyback Transformer Blues
I was quite disappointed yesterday having put so much hope into a bad snubber diode.
Now I am going ahead with an LCD panel install in my VT.
The main issue with this is that the composite video in the VT is very non-standard NTSC.
A Sony PVM monitor will display it but virtually nothing else will work. None of the cheap composite video converters that are readily available will handle this signal. It needs to be somehow conditioned or converted.
Lotharek.pl seems to be making something that may do the trick. I have asked them about it and am waiting to hear back,
The Medusa:
https://lotharek.pl/productdetail.php?id=135
This caught my attention due to the following description:
,, Special modes (unrecognised PAL-like and NTSC-like)
unknown PAL
unknown NTSC
Now I am going ahead with an LCD panel install in my VT.
The main issue with this is that the composite video in the VT is very non-standard NTSC.
A Sony PVM monitor will display it but virtually nothing else will work. None of the cheap composite video converters that are readily available will handle this signal. It needs to be somehow conditioned or converted.
Lotharek.pl seems to be making something that may do the trick. I have asked them about it and am waiting to hear back,
The Medusa:
https://lotharek.pl/productdetail.php?id=135
This caught my attention due to the following description:
,, Special modes (unrecognised PAL-like and NTSC-like)
unknown PAL
unknown NTSC
Re: DEC VT-101 Flyback Transformer Blues
Heard back from Lotharek. They said that they cannot guarantee that Medussa will work but that it likely will given that the Sony PVM does and that normal composite video devices display a shifted image. The Medussa can be configured to scale and shift vertical & horizontal.
So I am going to get it and see what happens.
So I am going to get it and see what happens.
Last edited by beatkamp on Thu May 09, 2024 1:51 am, edited 1 time in total.
Re: DEC VT-101 Flyback Transformer Blues
I also ordered a 12.1 inch 4:3 aspect 1024x768 LED display with HDMI controller board.
It is described so: ,,HD-MI LCD Controller Board with 12.1inch M121GNX2 1024X768 4:3 LED Screen"
I won´t bother putting a link to Ebay here as it will be dead in a short time.
It is described so: ,,HD-MI LCD Controller Board with 12.1inch M121GNX2 1024X768 4:3 LED Screen"
I won´t bother putting a link to Ebay here as it will be dead in a short time.