19V2000 Low HV (adjustment tops out low)

jasonsmith01

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My 19V2000 shows 12KV @ 0 Beam. If I try and adjust it maxes at 13.5KV and the game (Asteroids Deluxe) freaks out, beeps, resets and repeats that cycle.

Cap kit is being done now.

The HV Adjusment pot is almost maxed out as well.

Could this be an HV diode issue?
Where is normal for the pot to be upon re-install, don't wanna blow anything up.
 
I would remove R100 and R101 if they are present, and replace them with heavy gauge wire. Then check the + and - legs of the DB100 rectifier for +34v and -34v. Make sure F102 is clean and tight. Then check the striped side of D100 for +38v. These parts are all on the deflection board and constitute the low voltage power supply used as a starting point by the HV board.
 
What Douglas said.

It's a little odd that adjusting the monitor would affect the game board, as they are relatively separate systems, so I'm curious as to what's going on there. But definitely check power first, as suggested. (Also, make sure your game board is measuring 5.00V on the game board, using the 5V and GND test points on the board.)

If the HV is still low, yes the HV diode is the next most likely culprit. It's a common issue on these (in addition to recapping the HV cage). You'll need to clean out the boots, springs, and contacts, when you disassemble the old diode. Goof Off and Q-tips work well to remove the old grease. You need to have good contacts everywhere, else you'll burn up the boots when you install the new diode. I sometimes just solder them directly to the anode wires, if the springs are too rusty. (But keep the boots, as you still need the insulation.)
 
Just curious with these HV Diodes. They always look so yucky, is there a benefit to cleaning it all up and re-installing the original? After all the years one would think that the goo could be making things worse.
 
Just curious with these HV Diodes. They always look so yucky, is there a benefit to cleaning it all up and re-installing the original? After all the years one would think that the goo could be making things worse.


I always fully clean the boots and diode with Goof Off and Q-tips. Especially the insides of the boots, where the springs and contacts are. I believe the grease, as it gets waxy, can degrade the connection inside the boots (along with rusting the springs).

The connections to the diode need to be electrically very clean, as even a small amount of extra resistance will generate a lot of heat (as power = voltage squared divided by resistance, and the voltage is very high).

The outside of the diode being clean is less critical to the operation, but I clean it all while I'm cleaning and inspecting the boots and connections. I just use Goof Off, and a lot of Q-tips, until the Q-tips stop turning dirty.
 
Understood, thanks. My order of business is to finish capping it, check all the voltages that douglas mentioned and those resistors, clean the HV diode and fire it up and check the board for 5v.

I agree, it is weird that the board would react from the monitor adjustment. Was giving me ram type error beeps as well during the freak out that to me kinda screams low voltage.
 
Okay, so cap kit is done. R100 and R101 removed and shorted with 18 awg. Both resistors checked out at 4.5 ohms, not bad.

Cleaned the HV Diode and the connections but didn't replace it.

I have 38v at D100.
+36v and -38v at DB100.

Still can't adjust past 13 something Kv, game didn't reset this time but the HV adjustment pot is maxed. I also get a highish frequency jitter on the screen and slight breathing.

Must be the diode huh?
 
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