The Beast

Centralised area for notes about construction projects. Each project has its own sub-forum. In the sub-forums will be topics relevant to parts of that project (e.g., there might be a topic on CRT problems). If you start a construction diary, just post in the forum with your project name as the topic, and a moderator will create a sub-forum for your project.

Moderators: Dave Moll, Andrew Davie, Steve Anderson

The Beast

Postby Harry Dalek » Thu Mar 25, 2021 9:19 pm

This one has come about due to my 60s oscilloscope BWD 421A mains transformer kicking the bucket and i am unlikely to find a replacement so pretty much junk and now spare parts to me ..nothing lasts forever as they say .
IMG_0055.JPG

So been studying up on the GEC 1025H cathode ray tube,its the same tube as the 1000 H used in the D 43 Scope pdf posted apart from a different phosphor
its also equivalents are CV8299 SE4D31 what phosphor they use i don't know mines Green as in the phosphor PDF below .
This double gun cathode ray tube with spiral helix PDA was made by GEC-MOV. Also used in the Telequipment D43 scopes.
The tube 1074H is the same tube with different phosphor.
GEC CRT numbering system:
first two digits= screen size in mm =10
next two= screen type. 24 or 74 or 25
24= short, green, as P31 or GH.
74= as 24 with Aluminised screen (by adding 50 to phosphor type)
the 25 screen is short, green-yellow, as P2 or GL.
Letter indicates tube type/characteristic. H = two guns, with PDA.

The CRT is of interest dual deflection as it will push me to learn how to tame this Beast thus the name :wink:
Rather interesting Tube with 2 guns 2 sets of deflection plates for the Y The X i think it uses one half for either gun or perhaps you could use both for one gun ,unless i am misreading the D43 scope schematic .
So 2 EHT supplies also needed for this and some other supplies as shown in the D43 Schematic and data .
DSCN7314.JPG

DSCN7315.JPG

DSCN7318.JPG

DSCN7317.JPG

The Mu metal screen was rather grubby so cleaned that and gave if a paint job for the New Project ,i also had a case large enough to reuse for this
IMG_0056.JPG
IMG_0056.JPG (90.34 KiB) Viewed 206 times

Now the Tube needs to be mounted as its not safe with these power supplies ,so this step is where i am up to took a little while to work out the best way with the case i have .
The 2 silver panels and hidden door panel will hold the controls ,still need to cover holes back of case .
This CRT is all experimental depending on how well i can control it will depend on how it ends up ,what i would like it to do is similar 2 the 240 line 2 hz frame rate test on the Devil monitor but horizontal scanning so something like 120 180 240 line frame rate select ..using low frame rate i can use the audio bandwidth of my PC to display higher quality which would be lost trying a higher frame rate also the phosphor is a little longer so more suited to a low frame rate ..any case if it gets to this stage i will play around here.
I forgot if i can also do a dual display i will do something similar to the Binocular monitor but unlike having a sperate CRT for the scope and have a scope display below the video image on the same crt ,well want and can do depends first up if i can light this Beast .
OH well Fingers crossed one hand behind my back and here we go again ...
Attachments
1074H_D43_crt-wm.pdf
(613.06 KiB) Downloaded 10 times
Telequipment--D43--service--ID9899.pdf
(1.14 MiB) Downloaded 10 times
CRT screen phosphors-wm.pdf
(475.46 KiB) Downloaded 4 times
DSCN7327.JPG
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4588
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: The Beast

Postby Harry Dalek » Fri Mar 26, 2021 6:29 pm

Today CRT mounted fixed to case ,back panel blocked and 240 socket + panel switch added ..that's out of the way safe to start wiring now .
Attachments
DSCN7330.JPG
DSCN7331.JPG
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4588
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: The Beast

Postby Harry Dalek » Sun Mar 28, 2021 3:48 pm

Well the power supply is now mains connected So i have the HV negative and some of the high positive , dual 12 volt supply for the circuits ,What i had been thinking about was how to do the under 3kv EHT was going to use a cheap Chinese HV module with a lm317 to it to adjust the output this worked fine for the magnetically deflected CRT projects i have done ..
Looking at the old scopes old caps at its once EHT supply they are all rated at 3KV so we are looking at a 2 or under 3kv supply i will just make that via the mains transformer as i am doing for the Negative and lower positive supply in the few hundreds ,easy enough if you take care .

I could of hooked the heater up today but will leave that till i work on the the CRT plug i was more interested in working out how to mount the boards so i had enough space , so if every thing works out i can stick in another board or 2 ,lots of room in the case but not so easy to place every thing and mount if i go flat so going vertical easier to get to every thing and gives me lots of board mounting room .
Use what's laying around best way you can i say ...free that way !
Attachments
DSCN7333.JPG
DSCN7334.JPG
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4588
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: The Beast

Postby Harry Dalek » Thu Apr 01, 2021 6:59 pm

Bit more work today but bit flat out till next week due to Easter .
I had another thought about the EHT needed since this is a little experimental i may be a bit limited using the mains transformer for this which i am already doing for the high negative positives in the hundreds of volts and low dual circuit supplies , So i think i will try my ZVS flyback with a variable low voltage supply to it can run on 10 to 40 volts have to do some testing again but last test i got a touch over 1.200 volts to high 12.050 volts ..i will have to set it so its controllable from low 1Kv to 4kv keep it safe for the CRT .
DSCN9867.JPG
DSCN9867.JPG (145.42 KiB) Viewed 116 times


Mounted but need to add the variable dc supply this will adjust 1 to 4 Kv
DSCN7338.JPG


Next i needed a place to fix the the CRT connections to terminals easy to work out what goes where .

DSCN7341.JPG


So still a few things to do before even trying to power this up ,i would like to mount the deflection amplifier board and power it and know i have deflection on one set of plates feel saver to add the supplies to the CRT . next week some more the holidays some times get in the way well this time around .
Attachments
DSCN7342.JPG
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4588
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: The Beast

Postby Harry Dalek » Fri Apr 09, 2021 8:07 pm

Now up to deflection side and that works really safer to have that before the powering the cathode ray tube .
Most of the HV supplies are there i will see if i can get them closer to what's need here before trying to fire up the CRT , that's my job tomorrow.
Attachments
DSCN7343.JPG
DSCN7344.JPG
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4588
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia


Return to Construction Diaries - Electronic Televisions

Who is online

Users browsing this forum: No registered users and 1 guest

cron