A Tale of Two Chassis

ieure

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I have two K7000 chassis. #1 has a jacked up image (http://forums.arcade-museum.com/showthread.php?t=248925), but the width is fine. I've capped it, but not replaced the fly. #2 has a great image (capped + fly), but the image is way too wide. Probably 2" off either side. Both width coils seem to work — I can see the image size change, but can't bring it in enough.

All I want is one chassis that works 100%. Seems like it's easier to fix the width on #2 than figure out what's up with #1.

Chassis #1 has a .39uf cap at C38, plus another cap soldered on the underside. Chassis #2 has a single .39uf cap at C38.

I swapped the cap on the underside of #1 to #2. No change. I swapped C38 from #1 to #2, metering them both when they were out. Both metered good, but the image is still too wide on chassis #2.

I don't have other width caps for this thing, but I'm not sure that's what is wrong. Having the same caps work on one chassis and not the other tells me that something else is wrong, but I'm not sure what. B+ measures 130v on the near (furthest away from the tube) end of R302, which looks good to me.

What else should I be looking at. HOT? Or just track down width caps and hope that brings it in enough?
 
It was the best of synch, it was the worst of synch...

Anyway, I bet #2 is a 25" chassis.. The width coil looks different and the regulator is 130v vs 123v.
 
Or, look at the voltage regulators.

STR30130 (or, STR3130) = 25"
STR30123 (or, STR3123) = 19"


yes but you can put the wrong one in the both chassis and if that was the case you would not know the difference.

a visual is always better.

Peace
Buffett
 
width coil is different, heat sink on the vertical driver is bigger, and the B+ ceramic resistor is bigger..

Sorry , I didnt realize you had 25's. my first k7000 was supposedly a 19" (sold as such), but when I finally got it working, the image was too big.. a little research, and hmmm a 25" built on the 19" chassis...
 
most notable is the # on the chassis.

P447 = 19" in some cases it can also be a 13"

P538 = 25" in some cases it can also be a 27"

-----------------------

the heat sink that has the vertical IC.

about 1" tall = 19" in some cases it can also be a 13"

about 2-1/2" tall = 25" in some cases it can also be a 27"

-------------------------

most all 13-19" chassis have a black horizontal with coil.
with the same heat synk as listed at the top.

all 25-27" chassis have a wite horizontal width coil like on a 74xx, 75xx, U2000, 5000.
with the same heat synk as listed at the top.

--------------------------

19" zenith K7000a have a 10 pin fat neck and a different flyback foot print. and will fit on a 25" tube
with the same heat synk as listed at the top.

19" WELLS chassis are a 8 pin skinny neck.
with the same heat synk as listed at the top.
-----------------------------

25" zenith K7000a have a 10 pin neck and a different flyback foot print. and will fit on a 19" fat neck tube.
with the same heat synk as listed at the top.

25" wells have a 10 pin fat neck and will fit on a 19" fat neck tube.
with the same heat synk as listed at the top.
-----------------------------

all standard res K7000's including the K7000a neck boards will swap from one chassis to another, if a fat or skinny neck is what the tube is what is in the game.

------------------------------

any med res 19" k7000 neck boards will not be a direct swap without the proper modifications.

do not try this if you don't have an example to go off of.

------------------------------

there are some other clues like the VR's if they have not been changed out and are wrong

hope this helps.

Peace
Buffett
 
Okay, here's #1, correct-size jacked image:
NZiRn.jpg


Here's #2, way-too-big non-jacked image:
6z0Sc.jpg


Mean time, I guess I will reflow the header pins on #1 and see if that makes a difference.
 
pic #1 25"

re-flow everything see what happens.


pic #2 possible 27" 719x
see how the heat synk for the vertical IC has wings and you have a yellow and wite wire going to a remote board on the heat sink by the fly.

this would explain the larger image.

how about a swap on pic #2 i need a 27" and ill send you a rebuilt 25"
chassis PM me if you want to do this.

Peace
Buffett
 
pic #1 25"

re-flow everything see what happens.

Re-flowed the video input headers, connected it up to my Galaga, and everything looks great! Shouldn't have doubted you, buffett. Going to go swap it back onto the MVS and see what happens.


pic #2 possible 27" 719x
see how the heat synk for the vertical IC has wings and you have a yellow and wite wire going to a remote board on the heat sink by the fly.

this would explain the larger image.

how about a swap on pic #2 i need a 27" and ill send you a rebuilt 25"
chassis PM me if you want to do this.

Peace
Buffett
Will do.
 
This is true.

What are some of the visuals that would clue you in to the model? I've always gone by the VR.


usually 447,449 silkscreened on chassis and xxx123 vreg- 19"

usually 5xx on chassis, xxx130 vreg- 25"

BUt ive seem mixes and matches that didnt comply lol but most are either option a or option b there.

TO the op i forget which polypropelene cap is the width cap maybe c57?? Hell its been too long. It should be listed in the sticky. Basically get a k7000 width caps assortment from bob roberts and keep swapping caps till you find one that allows width adjustment to your liking.
 
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Conclusion: hooked it back up to my MVS-2, and it worked great. Looks like I'll be trading the 27" chassis to buffett, since I don't have a use for it.
 
that second pics going in the sticky, i frickin forgot all about the 27 inchers... good lord. GOod thing buffett is on his a game :D
 
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