WG 27K7501 - Replaced the Tube, now what

zosofan

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Hey Gang,

I picked up a Rush the Rock Alcatraz Edition that was missing the tube, but had the chassis. I found and installed a donor tube last night.

The image displays, but has a couple of issues that i'm hoping you all can help with.

1. The image appears to only be in shades of gray, no color present.
2. The image is of correct height, but is not stretching to the edge of the monitor, there is about 4" of black space on each side. I adjusted the width on the aux board to near max.
3. The image is pretty dim. I adjusted the brightness on the aux board to near max.

I have not done any caps, as i'm trying to evaluate whether to continue with this chassis.


eye thank ewe

greg
zosofan
 

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hey gang,

i was reading an ancient thread that popped to the top of the list. it was talking about problems somewhat like mine and was talking that the faint image is due to an incorrect yoke.

do medium res monitors have different yokes than what is found in a donor tv/tube?
 
Yes. If you swapped the tube, you need to swap the yoke also.

And for a 7500, make sure the connector to the transistor on the frame is connected properly...
 
the game was missing the tube and yoke when i got it, so i've used both the tube and yoke from the donor tv. i don't think that i've got a frame mounted transistor, but i'll look.
 
the game was missing the tube and yoke when i got it, so i've used both the tube and yoke from the donor tv. i don't think that i've got a frame mounted transistor, but i'll look.

Of even greater concern - I've found that the 7501 yoke is different than the 7502 yoke.

Do you have a 3-wire connector coming off of the chassis near the back right corner (closest to the tube)? If so, you need a frame-mount transistor mounted there. Without it, the picture will not adjust horizontally...
 
the game was missing the tube and yoke when i got it, so i've used both the tube and yoke from the donor tv. i don't think that i've got a frame mounted transistor, but i'll look.

Of even greater concern - I've found that the 7501 yoke is different than the 7502 yoke.

Do you have a 3-wire connector coming off of the chassis near the back right corner (closest to the tube)? If so, you need a frame-mount transistor mounted there. Without it, the picture will not adjust horizontally.

There were versions of the 7500 that had this transistor mounted on the chassis...
 
hey gang,



do medium res monitors have different yokes than what is found in a donor tv/tube?

I am not sure but was this a TV tube as a donor?? and Isnt TV's Tubes standard Res??? or can they be used as med. Res and all you need to do is have the right yoke??? Sorry for the HI Jacking the Thread....
 
no apology needed :) that's what i'm trying to figure out as well. lol.



I am not sure but was this a TV tube as a donor?? and Isnt TV's Tubes standard Res??? or can they be used as med. Res and all you need to do is have the right yoke??? Sorry for the HI Jacking the Thread....
 
I am not sure but was this a TV tube as a donor?? and Isnt TV's Tubes standard Res??? or can they be used as med. Res and all you need to do is have the right yoke??? Sorry for the HI Jacking the Thread....

just the yoke changes. same tubes. those Zenith tubes cropped up on all the U2000/U5000/K7x00 monitors of the era, and I was actually told by a guy at a tv shop that Zenith's designs were largely unchanged.

if it helps any, I got a Blitz '99 cab that had a warning label on the frame saying you had to change yokes too if you switched a U5000 to K7500 lol
 
just the yoke changes. same tubes. those Zenith tubes cropped up on all the U2000/U5000/K7x00 monitors of the era, and I was actually told by a guy at a tv shop that Zenith's designs were largely unchanged.

if it helps any, I got a Blitz '99 cab that had a warning label on the frame saying you had to change yokes too if you switched a U5000 to K7500 lol

Wow that great info. So basically if I have a 25 or 27 inch tube that has low empedence yoke (stds Res) then to make a med res you need the High empedence yoke... that is the only thing I can figure out that is different on the tube as all 25 and larger tubes have the same pinouts for the neck board. and I guess that the monitor board has to beable to produce the med res out puts.

This sound about right Mecha 187

Merry Christmas and GOD BLESS all
 
Wow that great info. So basically if I have a 25 or 27 inch tube that has low empedence yoke (stds Res) then to make a med res you need the High empedence yoke...

No, that is incorrect. The med-res yoke will also be low-impedance, but will be wound differently from the standard-res yoke...
 
soooo, are there any tv's that you can use that have a medium resolution coil?


It does not sound like it.

Not that I know of. Ask in the WTB section for a 7500 yoke. If you know whether you have a 7501 or 7502, ask for that specifically...
 
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