4600 Short Somewhere..

mcandrewsoun

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I had a perfectly working 4600 earlier today... Put a cap kit in, reflowed a few joints.. Checked everything twice..fixed one cap that was arcing (the 1500v one near the HOT). I power it up, and it trips my 3a circuit breaker.. HOT measures Open (?)..

If I unplug the Flyback, B+ voltage on the Vreg looks ok, however, no deflection whine.. Plug in the flyback, B+ goes low, and if I crank the variac over 7v, breaker trips.

So is this gonna be the flyback or the HOT? Im hoping its the HOT..Not sure how I killed her, and why it went open I pulled it and checked the terminals. If the Hot is Open, will the Fly look like a short circuit to the b+ (DC)?

Andrew
 
I had a perfectly working 4600 earlier today... Put a cap kit in, reflowed a few joints.. Checked everything twice..fixed one cap that was arcing (the 1500v one near the HOT). I power it up, and it trips my 3a circuit breaker.. HOT measures Open (?)..

If I unplug the Flyback, B+ voltage on the Vreg looks ok, however, no deflection whine.. Plug in the flyback, B+ goes low, and if I crank the variac over 7v, breaker trips.

So is this gonna be the flyback or the HOT? Im hoping its the HOT..Not sure how I killed her, and why it went open I pulled it and checked the terminals. If the Hot is Open, will the Fly look like a short circuit to the b+ (DC)?

Andrew

I bought a Pacman that had a K4600 I knew was bad. Put a cap kit in, Hot was shorted, replaced it and on power up blew fuse. Checked and the new HOT was shorted. I put all 3 of the plug in boards in my Frogger 4600 and they were good so I took the flyback out of the working Frogger and put it in the Pac 4600 and it worked for 8 hours and went dead again. Blown fuse and shorted HOT. Turns out the flyback from the Frogger 4600 died so I put yet another used flyback in with a new HOT and it has been working fine ever sense. So if you keep blowing the circuit breaker and everything else looks good I would suspect a bad flyback. My HOTs were shorted not open. How did you fix that 1500 volt cap? That could be bad I guess as it has something to do with the screen voltage and if shorted could kill your hi voltage.. Just a guess. Also look for a solder bridge and reflow the pins on the flyback plug.
 
Sure! You can take one off another chassis. :p

I /think/ Chad @ ArcadeCup is working on getting new ones made. I've been seeing a lot die lately (at least on here).
 
Ive got the HOT pulled now...Its reading open across ALL Legs (legs and case). Im guessing this isnt correct. ;-)...but looking at the circuit..If the hot is always off..no current should flow to ground...so maybe thats not a problem.. I dont see any shorts from any of the flyback pins to ground...Are there any areas anyone has seen that I should focus on? Thanks, Andrew
 
An update..I had hooked the yoke wires up incorrectly. The marking for the green was worn off, and the blue marking was between the two terminals, do I got them backwards. So now the monitor fires up, but I fried the vertical drive circuit I think. The drive trans (2sc1625) and diode (ISS81) are metering out as shorts.

What is a replacement for the ISS81? I cant find anything online.

Andrew
 
Luckily, the iss81 looks ok now that i pulled it..The vertical drive transistor is showing .1
v on the diode tester..Im assuming that is basically a short... Im gonna replace it and she what she does..
 
Glad to see you got it going. It's easy to get the wires and some plugs in backwards. That's why before I start pulling one apart I take plenty of pictures so I can look and make sure it's right before applying power.
 
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