William,
Ok, I finally had some time to look at this.
Replaced C508-C510 and no changes.
I think D504 - D506 were replaced prior, but I'll replace them again just for the hell of it.
I could understand the Tube being related to the Spot, but not the Spot Killer LED...
-- Brien King spammehere@arcaderestoration.com Visit the Arcade Restoration Workshop @ http://www.arcaderestoration.com Home of Cart Commander, the Ultimate Cartridge Cataloging Utility! Thursday, February 9, 2012, 7:29:41 PM, you wrote: > Replace C510. > I've been staring at the schematic for a 1/2 hour and it doesn't make sense > that the spot killer LED is on but you have a picture. That means that the > problem is likely intermittent (repeating at some frequency too fast for the > eye to see). If C510 is losing its ability to provide the proper time delay > for the SK circuit, then maybe the LED is not really on all the time, but > just partially or flashing fast enough to look like it's solid on. > Similarly, Q503 may be misbehaving due to the bad C510. Who knows, maybe > it's causing the center dot. A scope trace from D506 cathode would likely > reveal much. > I recommend also, since you are going to be in there anyway, replace C508 > and C509 since they are the same type and age. If C510 has failed, then you > might as well hit them all. Also, the diodes D504, D505, D506 (1N914 or > 1N4148) might as well be replaced. They are super cheap and easy to replace > so you might as well change them just to be 100% sure that they are all > switching properly and not leaking or something. A shorted D505 would cause > strange things to happen. > William Boucher > http://www.biltronix.com > ----- Original Message ----- > From: "Brien King" <spammehere@arcaderestoration.com> > To: <vectorlist@vectorlist.org> > Sent: Thursday, February 09, 2012 11:18 AM > Subject: VECTOR: Asteroids G05-801. Perfect picture for 5 mins then a circle > appears in the middle of the screen. >> Ok, I have an Asteroids with a G05-801 in it. When the game is first >> turned on, the picture is perfect. >> >> However, the Spot Killer is on, and after about 5 minutes, a circle and >> dot show up in the center of the screen. >> >> http://www.arcaderestoration.com/graphics/repair/AsteroidsCircleInMiddle.jpg >> >> I capped the monitor and here is what has been replaced so far in the Spot >> Killer section: >> >> Q503 >> Q506 >> R518 >> R528 >> R529 >> R523 >> R524 >> >> >> Any help would be greatly appreciated! >> >> >> -- >> Brien King >> spammehere@arcaderestoration.com >> Visit the Arcade Restoration Workshop @ http://www.arcaderestoration.com >> Home of Cart Commander, the Ultimate Cartridge Cataloging Utility! >> >> --------------------------------------------------------------------------- >> ** Unsubscribe, subscribe, or view the archives at >> http://www.vectorlist.org >> ** Please direct other questions, comments, or problems to >> chris@westnet.com > --------------------------------------------------------------------------- > ** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org > ** Please direct other questions, comments, or problems to chris@westnet.com --------------------------------------------------------------------------- ** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org ** Please direct other questions, comments, or problems to chris@westnet.comReceived on Sun Mar 25 22:48:25 2012
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