Oh oer I spoke too soon did I
I still have every confidence in you reviving it successfully ![ThumbsUp :-+](https://www.eevblog.com/forum/Smileys/default/icon_smile_thumbsup.gif)
Might have to leave it a couple of weeks for me to cool down
![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif)
Well bugger me one of the HT resistors just exploded. Fucks sake this is a demon scope.
Will order some more....
The existing ones or new you'd installed ?
Edit
Of the images you showed of it earlier it looked like the originals had already been changed from carbon comp to metal film and 1 watters. I used 2W metal film in the D83 I had.
Carbon comp has the advantage they tend to drift open so as not to create fireworks.
I didn't actually bother replacing the ones in there as the HV ones were all nice metal film ones and the problem was clearly with the capacitors rather than the resistors. It was one of those. It powered up fine for a few seconds then blew a hole in the encapsulation. Grr. One resistor didn't like the suddenly properly working HT supply!
At least the HT wasn't arcing over. It was dead silent and running nicely. The tube in it is super duper bright as well which is good. Could use it as a projector.
I will order some resistors when I fancy approaching this one again. And some diodes as these ones are mega-fragile after 40 years. I lost about 5mm of leg off each one unravelling them
![Smiley :)](https://www.eevblog.com/forum/Smileys/default/smiley.gif)
For now, some pictures:
Shitty old caps removed. The Efco ones were totally knackered. One of them had bulged at one end as you can see:
![](https://i.imgur.com/4WvvelB.jpg)
New caps installed. I had to remove the HT transformer to get the board out. It usually sits in front of this. No 22n caps around so I just bought twice as many 10n ones and wound them together.
![](https://i.imgur.com/muUrd8n.jpg)
Win. Ish. Before kaboom that is.
![](https://i.imgur.com/MWVLC5S.jpg)
And screw this I'm going to bed as it's half past midnight now.
There are some real muppets on Evilbay, there's a scope I'm interested in but although the seller claims it powers up and shows 2 beams, he also claims that he doesn't understand how to use it, fair enough, but he does not show any photos of it powered. I asked to see some photos of it powered and he has replied that he has stated that he does not know how to use it so he can't post any photos of it working
Tell him he's a numpty.
Well bugger me one of the HT resistors just exploded. Fucks sake this is a demon scope.
Will order some more....
The existing ones or new you'd installed ?
Edit
Of the images you showed of it earlier it looked like the originals had already been changed from carbon comp to metal film and 1 watters. I used 2W metal film in the D83 I had.
Carbon comp has the advantage they tend to drift open so as not to create fireworks.
Don't metal film resistors tend to have much lower voltage ratings? Such as typical 375V max? As opposed to carbon comp which have much higher voltage ratings.
Carbon composition resistors actually vary resistance depending on voltage so they just need to go away and die really. Apart from a few things like pulse handling, they are dead and should stay dead.
You can get glazed metal film ones such as the Vishay VR25 / VR37 / VR68 etc which is what will go in this. They are rated 1.6KV, 3.5KV and 10KV respectively. Most stuff is really low voltage these days (under 30V across all potentials) so they just don't bother with the usual cheap MF ones being more than 300V or so.