25" K7000 Dark Picture

[SirPeale]

I have a Lethal Enforcers conversion I'm trying to brighten, as shots aren't registering on screen.

The picture is quite dark.  I have done no other work on it.  Yes, I'm going to cap it.

One thing I did want to mention is that someone hacked in part of a Zenith flyback.  You know how on Zenith k7000s they have that weird kind of double flyback?  Yep...someone hacked that in there.  I'll post pictures when I take them.

[SirPeale]

I miss the days I could just grab a known good chassis and toss it on the tube to rule that out.  I'm thinking it's a tube issue.

[D_Zoot]

Could very well be.   I've got 30 year old 19" tubes here still sharp and bright,   but as time goes on I'm pitching one 25"+ tube after another...   mostly Zenith tubes.

Sometimes a good jolt from the B&K brings them around, but more often than not within 6 months the emissions have dropped to squat again.    Chassis doesn't matter,  K7's, U series, Kortek's.....    Zenith tubes just had cheap guns.

*Sigh*.............



D

[SirPeale]

And here I am with no rejuvinator.

*sigh*.

Times like this I wish I still worked for the arcade game operator.

[SirPeale]

Was finally able to pull this unit.  I've replaced 90% of the caps.  Unfortunately I'm missing at least three.  Not surprising.  These were caps from my stash, and I haven't done any work in a while.  I ran out of some more common caps a while back.

The picture is definitely better, but nowhere near what I'd like it to be.  And as these caps are in the power supply section, I'm not surprised that it's still a bit dark.

I have plans on getting more caps, but want to place a large order because I just got a lot of  stuff to repair.  This doesn't help me in the interim, though.  Can anyone help me with about six caps to tide me over?  LMK and I'll provide specs.

[qrz]

boosting the fil voltage a bit may help a bit.

also try this proceedure:
turn the brite and contrast levels to minimum
adjust the screen grid  +/- until the image is just barely perceptable.
then , adjust brite and contrast to desired levels.

this would still need to be done after a rejuve ......

qrz

[SirPeale]

qrz: thanks for the tips.  That was the first thing I did.  I've been doing this a few years now.

Rejuve would likely help a bit (maybe - it is a Zenith tube after all) but I don't have access to one any more. 

But it does still need those three caps.

[qrz]

what are the values ?

qrz

[SirPeale]

It's out in the shop now.  I know one is the filter cap (47 @ 160V, but I bump those to 200V) and I'll have to go check for the other two later.

Likely I'll just place my regular cap order and be done with it.  There was just some extras I was going to tack on, I'll just place a separate order.

[qrz]

if u have a 100uF@160v (or higher v ), use it .  over value not that critical on supply filtering.

qrz