Blurry GO7

[ToplessZ]

ok, I have a GO7 chassis that takes 20-30 mins to "warm up", before the picture gets clear.  It starts up really blurry and then clears up.  I have capped it-no change, replaced the flyback-no change, replaced the HOT-no change.  I even reflowed the solder on every part-no change....so it seems like a part is the kulprit to me-anyone know which one? (Adjusting the focus knob at first doesnt fix it either for those who are going to ask)
 

[SirPeale]

Could be a tube fault.

When you replaced the caps, did you replace them *all* or just the ones in the kit?

[Ken Layton]

Probably a weak tube. Connect to a rejuvenator and test it. That'll take the guesswork out.

[Lutus]

I have been curious myself but where can these rejuvenators be obtained and how much moolah are we talking for each one?

[ToplessZ]

its not the tube,,,I forgot to mention how this all panned out...

I had this chassis in my galaga cocktail...so I did all the repairs mentioned above..didnt fix it.  I swapped out the chassis with another one and it was fixed..so I put that blurry chassis away for about 6 months...then a friend of mine needed a GO7 chassis to repair his pole position,,so I gave it to him with the knowledge that it needed 20 mins to warm up to work.  When we installed it into his tube in his pole position the picture started out just a little blurry and took about 5 mins to become nice and clear.  after about three days though its back to starting up really blurry and taking 20 minutes to clear up.. 

sounds like a solder problem but i reflowed everything! so Im stuck....

[Ken Layton]

Check the soldering on the neckboard. One thing you should do too is to unsolder the picture tube socket from the neckboard. Now carefully slip off the plastic cover where the "focus" white wire goes into the socket. Resolder that wire and snap the plastic cover back on. Now resolder the tube socket back onto the neckboard and try it.

Another thing you might check is the monitor main board B+ power supply. Should be +120 volts as soon as you apply power and it should remain at that voltage. If the voltage is low when you first power up (like 110 volts or less) then you have a power supply problem. Maybe resistor R908 (not included in some capkits) is off value or the main filter capacitor is going bad or the B+ regulator transistors are bad.

WARNING: DO NOT ATTMPT TO MEASURE THE FOCUS VOLTAGE. YOU ARE DEALING WITH 8,000 VOLTS!

[ToplessZ]

Thanks Ken,, I'll try it out and post back when I have results...

[qrz]

had a sit down pole position a couple of months ago with poor focus .
focus voltage was fine going to the crt skt . was puzzeled until decided to check the focus pin OUT on the socket .
was loosing 3.5 kv !!   found corrosion around the spark gap that was bleeding off voltage .
 replacing  socket eliminated the problem.

qrz