DanV
Member
I have a few questions about the medium resolution variant of the K7000.
First, a customer had me repair a 19K7000 in his APB machine. Since the chassis had a white knob flyback, I replaced it while it was out. Between the flyback, trace repair, and caps, the monitor now fired up with a nice looking picture.
However, after about 30 seconds, the screen went blank, and then about 5 seconds after the screen went blank, I heard the loud "snap" and could smell burning electrical components. The new flyback had completely split in two. It has a horizontal crack in the center that left a clean break all the way around. The break was so clean that I thought I must have gotten a defective new flyback.
First question, does the medium resolution K7000 variant use the same flyback as the standard resolution version? I assumed it does since I was under the impression that the medium resolution variant was just a normal K7000 with a few hacks. But I want to make sure before I start blowing up a whole bunch of new flybacks trying to find the issue.
Next question, I repaired a different 19K7000 (std. res) and put it in the APB so that I wouldn't have to keep the customer waiting (this is actually how I discovered APB was a medium resolution game – stupid me). Needless to say, I was puzzled at first by the double image. I eventually gave up and went home, looked up the APB manual and discovered the problem. So now I have a non-working medium resolution K7000 and a working standard resolution K7000. Pardon me if this question is stupid, but is there a way I can take parts from the non-working medium resolution K7000 to make the working monitor into a medium resolution? I could easily move the satellite board, the capacitor on the foil-side of the chassis and copy the jumper modifications, but would this make a medium resolution K7000 or would it make a non-working K7000?
Finally, there was some sort of modification on the neck board, I believe it was jumping one of the neck pins to somewhere else on the neck board. If it's a common factory modification, it was a grey wire, about 4" long, if not, disregard that information. Whatever it was, it fell off the neck board after the flyback exploded. Does someone have a medium resolution K7000 they can look at and let me know the modifications to the neck board? Maybe a couple pictures?
The parts that blew when the flyback went:
- Fuse popped
- C57 shorted (is that normal when a flyback goes?)
- C36
- IC4
- HOT
- R103 reads a dead short – I thought it would go open?
- Haven't repaired it yet to test, but I'd imagine IC2 is bad as well
- Probably others I'll find, all the HV diodes tested fine, and there doesn't seem to be any additional burnt traces
If I can't modify the working K7000 to be medium resolution, I'll repair the non-working medium resolution chassis. Does anyone know if all the above components are the same between the two chassis? The both have the same voltage regulator, which is fortunate. I'm worried that I need a different oscillator to match the medium resolution frequency?
I appreciate any input or advice.
First, a customer had me repair a 19K7000 in his APB machine. Since the chassis had a white knob flyback, I replaced it while it was out. Between the flyback, trace repair, and caps, the monitor now fired up with a nice looking picture.
However, after about 30 seconds, the screen went blank, and then about 5 seconds after the screen went blank, I heard the loud "snap" and could smell burning electrical components. The new flyback had completely split in two. It has a horizontal crack in the center that left a clean break all the way around. The break was so clean that I thought I must have gotten a defective new flyback.
First question, does the medium resolution K7000 variant use the same flyback as the standard resolution version? I assumed it does since I was under the impression that the medium resolution variant was just a normal K7000 with a few hacks. But I want to make sure before I start blowing up a whole bunch of new flybacks trying to find the issue.
Next question, I repaired a different 19K7000 (std. res) and put it in the APB so that I wouldn't have to keep the customer waiting (this is actually how I discovered APB was a medium resolution game – stupid me). Needless to say, I was puzzled at first by the double image. I eventually gave up and went home, looked up the APB manual and discovered the problem. So now I have a non-working medium resolution K7000 and a working standard resolution K7000. Pardon me if this question is stupid, but is there a way I can take parts from the non-working medium resolution K7000 to make the working monitor into a medium resolution? I could easily move the satellite board, the capacitor on the foil-side of the chassis and copy the jumper modifications, but would this make a medium resolution K7000 or would it make a non-working K7000?
Finally, there was some sort of modification on the neck board, I believe it was jumping one of the neck pins to somewhere else on the neck board. If it's a common factory modification, it was a grey wire, about 4" long, if not, disregard that information. Whatever it was, it fell off the neck board after the flyback exploded. Does someone have a medium resolution K7000 they can look at and let me know the modifications to the neck board? Maybe a couple pictures?
The parts that blew when the flyback went:
- Fuse popped
- C57 shorted (is that normal when a flyback goes?)
- C36
- IC4
- HOT
- R103 reads a dead short – I thought it would go open?
- Haven't repaired it yet to test, but I'd imagine IC2 is bad as well
- Probably others I'll find, all the HV diodes tested fine, and there doesn't seem to be any additional burnt traces
If I can't modify the working K7000 to be medium resolution, I'll repair the non-working medium resolution chassis. Does anyone know if all the above components are the same between the two chassis? The both have the same voltage regulator, which is fortunate. I'm worried that I need a different oscillator to match the medium resolution frequency?
I appreciate any input or advice.