Recently repaired 4600 has no red.

TheDrewster

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I got my chassis back from Arcade Cup a couple weeks ago and when I installed it, I realized I had no red in the image and the green was waaay too bright. I tried a different tube and still got no red (one of which I accidentally necked afterwards...). Personally, I thought I just had two bunk tubes. Tonight, I rip a decent tube out of a junk cocktail I picked up yesterday and knowing full well it had all 3 colors. I swapped it in tonight and what do you know, still no red. Adjusting the red drive and red cutoffs make no change in the monitor. Needless to say I am very frustrated and this will likely be the last time I even dare working on these God-damn shitty-ass 4600 monitors (I had two fail right before I sold two games and I royally despise them and everything they stand for), but is there anything else I can try before sending it back for re-repair?
 
I got my chassis back from Arcade Cup a couple weeks ago and when I installed it, I realized I had no red in the image and the green was waaay too bright. I tried a different tube and still got no red (one of which I accidentally necked afterwards...). Personally, I thought I just had two bunk tubes. Tonight, I rip a decent tube out of a junk cocktail I picked up yesterday and knowing full well it had all 3 colors. I swapped it in tonight and what do you know, still no red. Adjusting the red drive and red cutoffs make no change in the monitor. Needless to say I am very frustrated and this will likely be the last time I even dare working on these God-damn shitty-ass 4600 monitors (I had two fail right before I sold two games and I royally despise them and everything they stand for), but is there anything else I can try before sending it back for re-repair?

Dumb question, but are you sure it's the monitor and not the game PCB?
 
If you have another 4600, swap the input cards.
If not, you might change out the 2 transistors for red on that card.
Good thing is that at least those are cheap and available from the Shack!
 
If you have another 4600, swap the input cards.
If not, you might change out the 2 transistors for red on that card.
Good thing is that at least those are cheap and available from the Shack!

I dont have any other compatible cards unfortunately. Which one is the Red transistor? And what type is it?
 
I would check the neck board transistor first. swap it with the green or blue one and see if the problem follows to that color.
 
I dont have any other compatible cards unfortunately. Which one is the Red transistor? And what type is it?

TR204 -> MPS-A70
TR207 -> 2N3904
are the red transistors on the input card.

The 3904's are cheap and available at Radio shack or Bob sells them for a quarter each. Worth having a few in the parts bin for sure!
The A70's, not sure about shack availability.

Also, check to make sure red is making it from the input card to the neckboard!
 
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