G07 rebuilt and dead

jimbodeanny

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This is the 2nd G07 I've rebuilt. The first one being the one in my centipede, which went smooth without a hitch.

However, this one is giving me problems. First off, I picked this one up at a great price. It WAS working when I grabbed it, but when I brought it home and turned it on with my Frogger, something popped and it was dead (no sound of high voltage, no B+, nothing.)

So, I picked up another rebuild kit from Bob Roberts and tonight I replaced the flyback, HOT, fuses and caps (and did the curl mod.) I plugged her in, turned it on and there was a tiny blue spark and that's it. Same as before. Absolutely nothing. I measured the AC voltage coming from the cabinet wiring and it was something like 124v. The 8liners/wei-ya monitor I have sitting next to it works just fine so I doubt it's that.

Right now I'm very puzzled and frustrated after putting in some time to fix up this chassis.

Ideas?
 
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Yes, it does have an isolation transformer. I did not replace the VR, just the HOT, flyback, fuses and caps.
 
Did you remember to put the insulator on the HOT?

I didn't see an "insulator" on the original and didn't add anything to the new one. Upon looking at Bob Robert's site, it would appear that I didn't add insulation. Is it safe to say that the HOT is toast now? What can I use as an insulator? I do have another replacement HOT I can use to try it with.

EDIT: It appears that high voltage never once reached the tube after I rebuilt this chassis as there was no pop to the anode when I discharged it and there was no pop to the filter cap either when I discharged that. If that helps at all.
 
Found the insulator on the old HOT. What should I do now? Should I replace the HOT again or try the one I installed already and add the insulator? I'm guessing one of the fuses probably went out?
 
1) You can measure the HOT to see if it's bad. if it is, you could put your old HOT in to see if it works with it.

2) put your insulator on.

3) Check to make sure your filter cap isn't all charged up before you do anything else. You might have popped your small fuse, and if so, the filter cap is probably full and ready to zap you....
 
Well, I'm stumped. I replaced the HOT and got the insulator on. I also replaced fuse 902 I believe (the one on the lower left of the chassis) as that appeared blown. I fired up the monitor and same thing. Looks like fuse 902 blew again with nothing else happening.

Thoughts?

Thanks
 
Did you replace the HOT with a good one? Make sure the wires soldered to the HOT aren't too close to the side wall where they may short?
 
I'll need to pick up some more fuses and turn the B+ down a bit. Since no power seems to be reaching the tube, I can't get a read on the B+ so I'll just turn it down and see what happens. I don't have a VR to replace the current one. Does Bob sell just those?

I really just want to get this G07 going so I can finish this Frogger. Maybe I'll just hunt down a working chassis and play with this one once this project is done...
 
Just reading this post and the G07 not even being mine still made me queasy. My hat goes off to you Jimbo.. If this were my G07, I'd currently be having to get pricing for not only a working G07 now, but also for a new window to replace the one the old G07 went through.. :(
 
The wires are soldered near the ends. I'm going to check the HOT and VR with my multimeter when I get home. I'll also take a photo of the HOT and post it in case there's something obviously wrong that someone spots.

Also, I'm going to stop at Radio Shack on my lunch break and pick up some replacement fuses for 902. They are 3A 5AG fast blow pigtail, correct? Oh, and I might also see if they have some diodes for D901-904 in case one of those needs to be replaced. What kind of diodes should I look for?
 
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UPDATE: PROGRESS!

Checked the HOT and VR and both appeared to be ok on my DMM. I then proceeded to check diodes D901-D904 and all checked out.

I mounted a fuse holder for 902 and replaced the fuse.

Then I looked at the B+ and noticed that the POT was all the way up. I turned it to about the halfway mark. I popped the chassis in, unplugged the degaussing coil just in case, fired it up, expecting another 902 fuse to blow and instead was happy to hear high voltage! I checked the B+ and it was at 104vdc. I adjusted it to 120 and now she seems to work! I didn't have a game plugged in so I haven't seen the picture yet. Right now, I just get a light green screen so I'm going to guess there'll be some color tweaking to do once I plug in Frogger, but so far so good!
 
That happened on a G07 I worked on not long ago. When I first got it the first thing that happened was the VR was bad, so I replaced it. Then the HOT blew the next power up. Turned out the B+ pot was cranked all the way.
 
Was probably going into shutdown after you repaired the initial problems.
FYI I have the pigtail fuses, hot and regulator for GO7 for a decent price. I also recently stocked the Sanyo 2SD869 hots and im working on stocking a few others.
 
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