Re: Asteroids G05-801. Perfect picture for 5 mins then a circle appears in the middle of the screen.

From: Brien King <spammehere_at_arcaderestoration.com>
Date: Sun Mar 25 2012 - 22:48:15 EDT

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!
>>
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Received on Sun Mar 25 22:48:25 2012

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