K4600 - Put a cap in wrong - now what?

neopolss

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I recapped a k4600 chassis for my galaga cab, after putting it back in, it kept blowing the main 110v fuse line in the cab. Shortly after, smoke billowed out and I discovered that I had put in a cap reversed (501 I think, the cap in the bottom right corner). I fixed my mistake, but I'm still having the issue of it blowing the main fuse in the cab, but the fuse on the chassis is still good. What should I be looking to replace?
 
try unplugging your monitor just to make sure the main fuse doesnt blow anymore, did you buy a new cap or just flip the one you put in backwards?
 
I had my blue and green yoke wires flipped. No more fuse issue. The cap was c608. Replaced and now i have a nice collapsed picture. Vertical transistor right? Is that a bottlecap one?
 
You have several transistors on the daughtercard, you need to test them all until you find the bad one or ones
 
I accidently did the same thing last week....same result, colapsed the picture...
I mean the EXACT same thing.....I had the B and the G. wires backwards, it blew a fuse in the main fuse block, I put the B and G wires in the correct place, changed the fuse and then had a collapse.....
It was the C1625 transister....
That's the NON green transister, on the one heat sink....on the H/V daughter board
 
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Replaced c1625 with an nte291 and now vertical size is back. I have some double imaging going on, but i thought there was a thread somewhere on adjusting it out.
 
Replaced c1625 with an nte291 and now vertical size is back. I have some double imaging going on, but i thought there was a thread somewhere on adjusting it out.

What kind of double imaging? Grab a pic if you can? You may need to adjust the pot down on the other daughter card, turned up too high it can stretch the image. Also make sure your B+ is in the 127-131vdc range.
 
Just measured my B+ and it was low, around 117v. Now it's set to 127.5V but the triple image is persistant. There's no scroll to it, it's perfectly stable but has three images. Is this L351 adjustment?
 
Just measured my B+ and it was low, around 117v. Now it's set to 127.5V but the triple image is persistant. There's no scroll to it, it's perfectly stable but has three images. Is this L351 adjustment?

No don't touch that, that is the rough adjustment for the sync.....
You want the vr pot on the OTHER daughter card....its the one that comes with the bob roberts cap kit.....when you install it, you put it on the BACK of the board, that way you can easily reach it to adjust it.....else it is tough to reach as it is sandwiched between the 2 daughter cards...
 
No don't touch that, that is the rough adjustment for the sync.....
You want the vr pot on the OTHER daughter card....its the one that comes with the bob roberts cap kit.....when you install it, you put it on the BACK of the board, that way you can easily reach it to adjust it.....else it is tough to reach as it is sandwiched between the 2 daughter cards...

the pot that comes with bob roberts kit is for the sub brightness and would not help here. I would assume one of the other transistors on the card has failed causing the double image.test at all transistors in the vertical section of the daughter card.
 
I believe it is the 2sa490 transistor. Is there a good cross refence for this?
 
Yeah Bob sells those, he refers to them as a TIP30, but I'm sure if you tell him you need a A490 for a 4600 he will know what you need.....
 
Subbed it for a nte153. It still had the triple image, but adjusting the vertical hold cleared it up. Interesting that the hold wasnt making it scroll, just solid triple imaging. Either way, all fixed now, i have a great picture. Resolved.
 
Yeah, if it is scrolling REALLY fast, it will give that effect, glad to see this resolved.....
 
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