G07 HV Shutdown

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Hi;
I have a Missile Command with a G07 that goes into HV shutdown when turned on. I wasn't sure why the monitor was not working and it appeared to come on when power was applied so I put my HV probe onto it, fired it up and the voltage goes up 26+kV then shuts down.

I had rebuilt this chassis about a year or two ago and the game played fine. I replaced the HVT and a cap kit, all other components were good.

I checked the following transistors and all look good:
X04
X902
X901
X701
X501
X01
X401
X402

Any suggestions as to which component would cause this to occurr?

I'm leaning towards IC501, only because I really have no idea!

Any help would be much appreciated.
Thanks in advance
Jeff
 
Check R908......47K 1/2watt....you will have to lift a leg out of circuit to get a correct reading.

Edward
 
OK, thank you for the suggestions....

I will pull R908 and test first and see if that is the culprit.

If that does not do it, I will pull X701 but by pulling that, would that not effectivly prevent the HV from being genetrated at all?

Thanks
Jeff
 
Hi;
I have a Missile Command with a G07 that goes into HV shutdown when turned on. I wasn't sure why the monitor was not working and it appeared to come on when power was applied so I put my HV probe onto it, fired it up and the voltage goes up 26+kV then shuts down.

I had rebuilt this chassis about a year or two ago and the game played fine. I replaced the HVT and a cap kit, all other components were good.

I checked the following transistors and all look good:
X04
X902
X901
X701
X501
X01
X401
X402

Any suggestions as to which component would cause this to occurr?

I'm leaning towards IC501, only because I really have no idea!

Any help would be much appreciated.
Thanks in advance
Jeff

before doing anything, change out c511. I have had a couple of chassis over the years go into hv shutdown because of that cap. Even if you did a cap kit at some point, try changing c511 again.
 
I pulled C511 and it tested good but I went ahead and replaced it since I already had it out..

I pulled and tested R908 and it came in at 56.4K ohms and since it appears to be a "critical" component, I am hoping it is the culprit. I will replace that and give it a try.

Thanks again for the suggestions and I will be posting the findings tonight.

Jeff
 
NICE!

The monitor stays on - does not shutdown on HV!

Now I have another problem, I cannot adjust the B+, it stays around +118vdc no matter which way I turn the pot, there is no change of the voltage....

Also, I have no green!

I am going to search the forums for a solution.

Thanks everyone for your suggetions and help.

Peace
Jeff
 
X103 or X104 on the main chassis board for your green issue.

You can test it too, figure out the red & blue transitor, take 1 of them out and insert it in green's place. Green will come back and 1 of the other color will be gone.

NICE!

The monitor stays on - does not shutdown on HV!

Now I have another problem, I cannot adjust the B+, it stays around +118vdc no matter which way I turn the pot, there is no change of the voltage....

Also, I have no green!

I am going to search the forums for a solution.

Thanks everyone for your suggetions and help.

Peace
Jeff
 
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