Atari arcade Asteroids monitor dead -

[Bruce G]

Howdy gang - a good customer of mine gave me a nice original Asteroids arcade game. 
Video not working. 
Monitor was made by Electrohome, model G05. 
 
I pulled out the GO5 - 801 regulator board ( because it was easiest ) and did some component testing

Both 5A SB fuses good
Both darlington transistors totally open 
Both zeners dead shorted
One 7200 uF storage cap is OK, the other has 20 % leakage ( and is badly out of form )


I ordered replacement caps from Mouser, the rest of the parts I have on hand in my shop. 

This is my FIRST go-round with an X-Y CRT monitor repair attempt.

I have overhauled a number of vintage B&W televisions in the past, and have over 35 years repairing tube and SS equipment for a dealer in my town.  But no monitors....... 

So with that said - I don't want to roast my repairs on power-up.  I would like some feedback on how to proceed after refreshing the regulator board.  I would like to see where the system status is after doing just this repair.  If the CRT isn't dead - I'll proceed to refreshing caps & checking components on the other boards.  At this point, I don't even know if the H.V supply / flyback transformer are any good.

Mos of all - I don't know if the failure of the regulator board was an on-board problem, or some other failure down stream.   

Helpful advice is greatly appreciated. 

[Bruce G]

I overhauled the regulator board with new components to replace the damaged ones.  If works well now.  But the boards down the line from it are damaged, so it'll be one board repair at a time - as my time allows. 

[Chris-socal]

Hi Bruce: 
Those are common monitors in the early games.
Sounds like you got caps which is really important.  Those are all getting to the point where Flybacks go out on them too, be sure to check the HOT and voltage regulators too.
Always discharge the 2nd anode cup on these too.
If you need specific parts reach out to Bob Roberts, they know that unit well and they usually have Flybacks in stock. www.therealbobroberts.net
Here is a link to a G05 repair video, I'm at my  9-5 job today so I didn't watch it in detail, but he talks through some of the component specifics and potential issues.

Please keep us updated.

Chris

[Bruce G]

Thanks much Chris - having a source for parts is a huge help.  I did a quick look at the EHT / flyback box - It's obviously had a hard life.  I need to order caps for it, but the semis on it check out.  With little to zero experience with these, I need all the help I can find.  I pulled the X-Y deflection board and power section.  The board looks good with no wonky repairs.  I''ll recap it and check the other components as time allows.  I found the the X channel power amplifiers (2N3716 and 2N3792 ) were both dead shorted.  I have those parts on hand.  BUT - I don't like the idea of just replacing parts and then firing this thing back up.  These semiconductors are getting expensive and I tend to feel there has to be a reason for the component failures.  Because one channel is bad - that would seem to eliminate the regulator as the cause of the fault.  If it had been the regulator board that caused the failure, I would think that both channels would have cooked.  I did test the heater of CRT for continuity ( it shows 3.2 Ohm ) but I have no other way of testing it - at lease that I'm aware of.  So I feel like I'm flying blind.  I really don't want to waste money destroying replacement parts.