WAGDAG
Active member
I have been working on a K7000A this weekend and almost have it licked with the exception of one issue. The top half of the image seems to be drawn twice...kind of. There are horizontal lines across the top half at all times, but there is something else going on that can be clearly seen on the cross hatch screen. The top half has solid white lines across but the dots are also drawn twice. when I adjust vertical size (remote board) or adjust 50/60hz POTs, the bottom half adjusts perfectly and the top half expands vertically as it should, but the second "layer" on the top half also gets taller / shorter at a different rate. I can't adjust it to lay on top of the primary cross hatch as seen in the pic.
I picked this up on Ebay so I do not have any history.
- Installed full cap kit and reflowed most of the chassis and the entire neckboard.
- Replaced green drive POT (green was missing)
- Removed and straightened out the three neckboard transistors that were crushed and repaired lifted pads.
- Swapped both IC1 and IC2 with a parts board I had kicking around; no change
- Tried chassis on another tube/yoke combo; no change
Looking over the schematic, I tried to check for continuity between each pin on both IC's and the next component downstream (look for open traces) and everything seems to be making good connection.
Not sure if this info is helpful - I found incorrect value caps at C56 (22uF) and C57 (47uF). Both had 100uF 160v caps installed. Also found C21 had leaked and rotted a leg off which may have been one of the causes for it going into shutdown prior to the cap kit. Could this have taken out something else? Why would someone install caps with values so far off?
Can someone please point me in the right direction as to where I can look for potential problems or perhaps explain what components come into play that I should be testing?
Thanks for any suggestions. I would really appreciate some advice.
I picked this up on Ebay so I do not have any history.
- Installed full cap kit and reflowed most of the chassis and the entire neckboard.
- Replaced green drive POT (green was missing)
- Removed and straightened out the three neckboard transistors that were crushed and repaired lifted pads.
- Swapped both IC1 and IC2 with a parts board I had kicking around; no change
- Tried chassis on another tube/yoke combo; no change
Looking over the schematic, I tried to check for continuity between each pin on both IC's and the next component downstream (look for open traces) and everything seems to be making good connection.
Not sure if this info is helpful - I found incorrect value caps at C56 (22uF) and C57 (47uF). Both had 100uF 160v caps installed. Also found C21 had leaked and rotted a leg off which may have been one of the causes for it going into shutdown prior to the cap kit. Could this have taken out something else? Why would someone install caps with values so far off?
Can someone please point me in the right direction as to where I can look for potential problems or perhaps explain what components come into play that I should be testing?
Thanks for any suggestions. I would really appreciate some advice.