G05-801 not working

tordyvel78

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Hi guys!
I need some help with my Asteroids monitor. Its not all dead... I have neck glow. Thats it.
I have searched the forums but no luck.

Played around with my multimeter and checked all the voltages on the regulator board.
Looks fine until i connect something to it. Doesnt matter if its the deflect or HV.

As soon as i connect something to it, pin 1 & 2 drops to 8v.
Unloaded its 28v. I checked the current going to the HV and its only 90mA (deflection not connected).
I replaced the zenerdoides (ZD100, ZD101) and the diodes (D100, D101) because they looked like crap. Reflowed all pins. Same problem.
What do you think?
 
Last edited:
Also P900 on the HV.

1. 160.1 VDC (400/-200)
2.
3. 160.4 VDC (400)
4.
5. 36.6 VDC (90)
6.
7. 8.2 VDC (25)
8. GND

Does this mean the trafo is ok?
 
Anyone?
Maybe its something that dragging the volts down for saftey reason. What can it be?
That means its something wrong with the HV AND the deflection board.
 
Not in front of a schematic or parts right now. Will be tackling a few of these next week. In the past, big issues have been NUMEROUS broken trades/cold solder joints/loose parts/bad parts on the regulaotr board. Go completely through that and make sure you have continuity between each and every trace/part on that board. When it is removed, people wiggle the connectors etc. and after 30+ years of it, things break. When you have verified EVERYTHING is correct, recheck your voltages etc. I cannot stress this enough. I had multiple issues with a regulator board and it wasn't till I fixed all the issues that the monitor actually worked and I was able to troubleshoot the minor issues in the HV cage and on the deflection board. You did also check each transistor on the heat sinks on the side correct? When those are 100%, it makes troubleshooting so much easier. Your voltages sound good but without my notes and manual in front of me I can't help much. I have only done 2 of these in the past year or so.

Hang tough and maybe somebody else will jump in.
 
I removed the diode with minor results.

P900 pin are now
1. 203v
3. 204v
5. 46v
7. gnd
8. 10.15v

Not supergood, but something...
Looks like if i double voltage in, i double it out too. Does that mean
my trafo is OK?
Feels like the trafo is the hardest to replace.

Can it be the regulator that are really really weak? I still have
original transistors and big caps.
 
80% of problems with that monitor are in the low voltage section and the big bottle cap transistors. Unplug the connectors to the transistors and check if they are shorted or if the transistor case or pins are shorted (touching) to the metal they mount thru.
 
Seems like Q100 is bad. Have no connection with the collector.
Does anyone have cross reference to the 2N6057?
Ok with MJ3001?

Thanks!
 
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