OK, after playing about a dozen games, I examined the HV PCB again. The resistors are the parts that get relatively hot, but that's probably normal. All other parts feel fine.
I put the HV PCB back in it's place.
I again sat down and examined the screen. For a start: It looks amazing after 25 years !!!!!!!!!!!!!!
Yes its' been in storage for quite some time, but still....this game saw a lot of action, despite it's good looks. The coin counter is around the 77000 mark (so it earned a lot of money for the operator !).....
While playing, the picture is great.....I totaly LOVE vectors !!!
I had never played SW on a real arcade cab, only in MAME with joystick control (which completely sucks of course). The control of the yoke is amazing and adds SO much to the game...
Anyway, when the game is running in attract mode, I do see some problems with the screen. First, there is a convergence problem in the lower left corner. It's possible that this can easily be corrected with a degaussing coil. However, it can also be that it already has been corrected by the internal degaussing....
Then, there is clearly some geometric problem.....my guess is that that is a matter of replacing caps on the deflection board.
Also, when the letters are displayed, the letters are not completely perfect. They seem a bit "crooked". I also think this can be a cap problem.
Then, the most obvious problem, is that the screen starts to flicker when there is a LOT of text on the screen. During gameplay, there is no problem at all....This again could be caps, maybe even the big blue on the power supply.....
So, I took the deflection and game PCBs out, and brought them home to work on them. They look amazingly good, especialy the game PCB set.
Check out the pics.....