19V2000 dim in middle

Altan

Active member
Joined
Jun 15, 2009
Messages
1,105
Reaction score
10
Location
Georgia
I've been bringing an Asteroids Deluxe back to life... I've got the game working and now the monitor is showing images.

I'm seeing two things that need to be addressed:

1) Image is dimmer in the middle

The brightness in the middle of the screen changes while its powered on, ranging from slightly dimmer than the non-middle to very dark.

I've done a bit of research and it seems the HV diode might be the problem?

Also, I haven't done a cap kit on the monitor yet. Is this a symptom that might be solved by a cap kit?

2) Image is too large and the size seems to occasionally bounce between "too big" and "even bigger"

I suspect I should start by adjusting the X/Y linearity pots. That may change the "too big" image into the "right size" image. But I suspect it will not address the image size change.

Note that the letters/graphics are not "crinkly".

I'm worried this one points to some HV issues... which I didn't want to mess with.

Thanks in advance for any thoughts

... Altan
 
The image size issues sound like blooming, and a cap kit should fix it. Not sure about the dimness - can you post some images or video? Also, look at the spotkiller LED on the deflection board and see if it's flickering on or not.
 
The image size issues sound like blooming, and a cap kit should fix it. Not sure about the dimness - can you post some images or video? Also, look at the spotkiller LED on the deflection board and see if it's flickering on or not.

Blooming is not cured by a cap kit, not that a cap kit won't help because it will.
 
Thanks!

Any suggestions regarding cleaning the diode?

I just cleaned a diode like in on an old B/W monitor. I've done a few, but I don't remember what I did with the first couple, but I used some "Purple Stuff" on this last one and it was quick and easy. ... wear gloves because Purple Stuff is some crazy strong stuff and will make the top layer of your skin slough off. ... But it's my new favorite cleaner, I used it for degrease'ng REALLY nasty stuff, cleaning tape residue off of glass/plexi, and just tonight found out that it's really (REALLY) good at cleaning flux off of a board after I work on it. You're supposed to dilute it, but... really... screw health and safety, that's my motto. I want job done, and I want it done quickly... finger prints be damned.

EDIT: Oh, and don't forget to put some dielectric grease back on the diode ends and all that jazz when you get done cleaning it.
 
Last edited:
I'm confused by the dielectric grease comment. My understanding is dielectric grease is an insulator. Why would it be good to put this on the metal connectors of the HV diode?

I assume you meant putting it on the diodes metal connectors...

(oh, I'd appreciate a link to this stuff.. Just so I don't get the wrong thing)
 
Last edited:
Quick follow up... I built my own little discharge tool (clips, resistor, wire...). Did the discard, worked great.

I opened the HV cage and saw something that looked like

[flyback][wire][cup-like thing][diode][cup-like thing][wire][transformer]

I very gently touch the wire (after all, I was a little wary of it...). The diode then swung down 10 degrees. One of the leads had apparently broken (well before I touched it). In the "swung down" position, it was no longer connected to one of the cup-like things.

it's pretty amazing the monitor was working as well as it was! Is this even possible?

... Altan
 
Last edited:
I'm confused by the dielectric grease comment. My understanding is dielectric grease is an insulator. Why would it be good to put this on the metal connectors of the HV diode?

I assume you meant putting it on the diodes metal connectors...

(oh, I'd appreciate a link to this stuff.. Just so I don't get the wrong thing)

It is an insulator, but it's also acts as a protective coating to fight corrosion and keep the connection clean. The pieces will be presses together so the grease won't get in the way of that, it's just there to keep everything corrosion free. If you ever get your spark plugs in your car changed, you'll notice they put it in their boots as well (and they come from the factory like that)... same deal, just there to keep the connection clean.

Yes, I meant putting it on the connectors on the end of the diode and a little in the cup they sit in. Not a lot, because it can run when it heats up, but just enough to cover the connections.




As far as the diode swinging down... I'm not sure about that. Lemme check my Battlezone real quick, I was just working on it and the HV cage is off so I should be able to get a good look at it.
 
I'm assuming it snapped over where either one of those amazing manly colored circles is? If that's the case you -should- be able to solder that wire back on to the little spring cup that the diode plugs into and she should be good to go.

FWIW, with the amount of juice that goes through there, you're lucky the machine wasn't on when it let go... it could've made a mess out of your HV board there.

attachment.php
 

Attachments

  • 19v2000hvdiode.jpg
    19v2000hvdiode.jpg
    66.2 KB · Views: 63
Scucci,

No, it break where the cup thing is. Here is an edited version of you picture... see the yellow circle. (Sadly I don't know how to upload an image and get it to appear here... so it's just an attachment below).

I tried to take several pics, but they were terrible. It's because I still have the HV cage attached to the monitor frame and too much stuff is in the way.

So now it goes

[flyback][wire][cup-like thing][diode] just hanging ... not connected to the other cup.

I assume I need to pull out the old lead from that cup.

... Altan
 

Attachments

  • diode-break.jpg
    diode-break.jpg
    43.3 KB · Views: 24
Buy and replace the HV Diode.

Answer to your next question: Arcadeshop, Bob is out.

Thanks mind reader Dokert.

I may have a buddy local that has one... I'm checking.
 
I used a smaller camera and got some pics. While taking these, the HV diode just fell out completely.

hvdiode1.jpg


hvdiode2.jpg


I hope those "bent outward" ends of the HV diode holders are ok...?
 
I used a smaller camera and got some pics. While taking these, the HV diode just fell out completely.

hvdiode1.jpg


hvdiode2.jpg


I hope those "bent outward" ends of the HV diode holders are ok...?

That diode looks corroded as all hell... clean those ends up and see how she does. ... as far as those holders?... wow. I don't know about those.

Maybe clean it, shove it in there, and see if you can zip-tie (or something?) the holders into place so the diode will be secure and maybe hold a connection? ... wowsiers.
 
Scucci... I'm new to this an assuming the diode should have metal leads coming out each side... Is that not the case?
 
Scucci... I'm new to this an assuming the diode should have metal leads coming out each side... Is that not the case?

Unless I'm not seeing what I think I am, it looks like there's one coming out of the right end of the diode (as the picture is facing), I can't see anything on the other side and I do remember mine face opposite directions (because I'm anal retentive and remembered that detail...)

I took mine out and cleaned it up real quick to get a picture of it and the leads. There's not much there for leads, just a couple of little stubs.

attachment.php


If you don't have ANYTHING coming out of one of the ends... then, yeah... you're going to need a new diode.
 

Attachments

  • 19v2000hvdiodeout.jpg
    19v2000hvdiodeout.jpg
    110 KB · Views: 55
Thanks!

There was a very tiny lead on one side, but it immediately fell off when I touched it. So there are no leads on either side :(

I'm surprised how small the leads are you your HV diode. How do these connect when you put them into the holders?
 
Your HV diode is bad. The green shit is known as vertigrae, which is corrosion. When it gets bad, it rots through the metal.
 
Back
Top Bottom