RE: Starwars and Amplifone Issue

check the two big resistors on the deflection board. They may have been replaced with wirewound reistors. The two current sense resistors MUST BE non-inductive.

-Scott
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From: owner-vectorlist@vectorlist.org [owner-vectorlist@vectorlist.org] On Behalf Of PJ [pj1@shaw.ca]
Sent: Sunday, March 21, 2010 9:29 PM
To: vectorlist@vectorlist.org
Subject: VECTOR: Starwars and Amplifone Issue

Hi All,

After finally getting around to getting my Amplifone Star Wars up and running, I've got an issue that has me stumped.

With the HV board being suspect, and after a good run through, I was awarded with the usual red-is-dead, dried out capacitors, and board cooked by poorly placed bypass resistors. After a complete overhaul consisting of replacing virtually every active device except the 555, recapping with revised values, installing Dale 50ohm 25W resistors on the heatsink, fuses in the power leads to the board and installing a Cinelabs transformer, I was awarded with a running HV that ran through the adjustment ritual without a hitch 19.5KV, shutdown works 100%, B+ is 181v. Used the Dale resistors since they're small, stay cool, and mount easily to the heatsink. The newly overhauled board runs cool as a cucumber.

While I was at it, I recapped the deflection board, and installed a fresh set of output and predriver transistors. All connectors have been cleaned, and the ground/power mods per John Robertson have been done. All the brown jumpers have been removed on both the HV and deflection boards.

Now comes the problem: the vectors have issues lining up on motion objects, Text like the "Flight instructions to Red five" look like something from Bob's Honky-Tonk Country Bunker. The letters D, B and A amongst others have worst issues: the loops on B's are slightly too long, and the lower right lines on the A's are bent in toward the left. The Star Wars logo has issues with the top line of the S and the left side of the letter. Horizontal lines like the top of the shield indicator, insert coin, and princess leia text are crinkly, but are static in that they are not dancing like a bad grounds or power supply ripple. The level screen's mini Death Stars look like ratchet gears. Super bright objects like a shield level change, the closest green attract mode text or fireballs are so bright that the vectors grow out of focus, but the picture does not swell or change size.

Display on a scope is 100% normal using the testpoints on the AVG and everything looks 100%. The board passes all self tests without an issue, and the brightness test screen looks ok. If I raise the X and Y size on the AVG to almost clipping, and lower the corresponding pots on the deflection board, it improves, but nowhere near where it should be. Shrinking the screen down displays an improvement as well. Aligning the BIP and linearity does not solve the text but tweaking the BIP will make the Starwars logo look better, at the cost of messing everything else up, like say the tie fighters or the trench vectors.

On a whim, I replaced the 15V regulators and electrolytic caps on the AVG, since the positive one had low output. This did nothing to help/worsen the issue.
Could there be an issue with the Cinelabs HV transformer or board causing this issue? Any other insight would be appreciated.

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Received on Sun Mar 21 23:51:18 2010