Electrohome G08 vector repair

80sarcade

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I have a flaky G08 vector monitor. I have installed a cap kit and re-flowed all the pin headers. The monitor works for a few minutes and will then shutdown. I have neck glow but that is it. From what I can piece together it appears to be the HV section.
I have exhausted my skills level and now an looking for someone to fix.

Any recommendations on someone to fix?

I have the Sega Multi kit coming and now is the time to get my Star Trek fully running.

80sarcade
 
I have a flaky G08 vector monitor. I have installed a cap kit and re-flowed all the pin headers. The monitor works for a few minutes and will then shutdown. I have neck glow but that is it. From what I can piece together it appears to be the HV section.
I have exhausted my skills level and now an looking for someone to fix.

Any recommendations on someone to fix?

I have the Sega Multi kit coming and now is the time to get my Star Trek fully running.

80sarcade

there was another thread on this a while back, there was someone here on the boards who indicated they can fix these. When I had mine fixed, it was done by Arcadecup, but he no longer does the repairs. Also, P&L Monitor in Baldwin Park has indicated that they can fix these but I think it's been a number of years since they actually worked on one. I guess that would be a last resort. Also KLOV'r Mongo on the boards is very knowledgable about this monitor...
 
If you lose either axis of deflection, the unit will shut down the high voltage.. I thought it would also shut down neck glow too.. Id reflow all the solder joints on the HV pcb..Sounds like a joint is opening up when it gets hot.
 
Looks like I will pull the monitor and try again.... Wish Chad or someone would offer to work in these again. With the Sega Multi kits, I am sure I am not the only one with a kit and a non-working G08.

Any other suggestions are always welcome. :)

80sarcade
 
I fixed a G08 that was doing this same thing a long time ago.

Turned out to be the IC on the high voltage board. Its not some generic chip though. Its a custom part that was made for or by Electrohome.

However, this does sound like a case of a failing axis either because of the monitor or because of the game board. Have you gone over your boards and power supply in the game?
 
I sure hope it is not that custom chip....
I have checked the power supply, voltages are good. I have pulled the boards out and the connector at the end of the cage. I re-flowed the connections on that board.
The game starts and even when the monitor goes out, the game still plays blind.
I have done a cap kit on the monitor and it was new transitors. I made sure to get the correct ones and not use the ones from the Bob Roberts kit.

Thanks everyone for all your suggestions.
80sarcade
 
Got a scope? Just because game is playing doesnt mean the vectors are working. Use the scope to see what the boards are sending to the monitor, then monitor the outputs just before the yoke. Either on the paddle boards or the yoke fuses. Make sure the scope is set to the correct volts/division...The output swing on the yoke is +-36 I think.

Andrew
 
I have read them. I did the transitor mod when replacing them.

Looks like I need to pull the monitor, again, and really go over it, again...

Thanks again, I will update on my progress.

I REALLY want to get the Sega Multi add on board in there and start playing. Looking forward to some Space Fury and the others which I have only played in MAME.

80sarcade
 
Take some voltage measurements on the X and Y input signals. You should get a few volts on the AC scale and you should see them change. The X signal is a little higher than the Y.

Unplug a couple of fans so you can hear better. You should be able to hear the 'chatter' of the changing signals going through the yoke.

These tests will help you see if you're getting deflection from the XY boards and help determine if it's making it all the way to the yoke.
 
II made sure to get the correct ones and not use the ones from the Bob Roberts kit.

Ok. Before I order a cap kit from Bob Roberts, can anyone advise me on why this may not be good idea? (I haven't even tried firing up my non working Star Trek, so I don't know if the monitor is working, but had been about to order a cap kit anyway).

Thanks.

Darren Harris
Staten Island, New York.
 
the original output transistors are 2N6259's they have not been made in a couple of decades, Bob ships 2n3716's with his kits. They last about 5 minutes... there are some other modern day transistors that will work see the FAQ for part numbers...

mh
 
the original output transistors are 2N6259's they have not been made in a couple of decades, Bob ships 2n3716's with his kits. They last about 5 minutes... there are some other modern day transistors that will work see the FAQ for part numbers...

mh

Mark, given a choice would you use a 2N6259 or one of the modern day transistors that work?
 
Ive used both...The replacements were cheaper, but you gotta get them from Mouser or Digikey.. I think they both work fine.. You can also get equivalents for the MPSU10 & MPSU60, and they use a different heat sink, so away with those copper foil heat sinks.Do the mods in the FAQ. Voltage & flipping the transistors. Make sure everything is working PERFECTLY before hooking up the yoke. Those .13 ohm resistors must not be more .13 or they will engage the current limiter, and your output will look squashed. What I hate about these are all the short wires tying the boards together. it makes working on it on the bench a pain. I usually just leave the HV cage unhooked until I get the deflection perfect. Thats something I do like about the 6100, is that everything is on plugs and easy to take apart. The G08 looks like a science fair project..lol

Good Luck.

Andrew
 
I would stick with the original 2n6259 if you can locate them... I have some pulls that are good if need some.

mh

Would that be the same thing that Bob has?
 
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