Breakout (needing help)

Scucci

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So, I've been working on my Breakout PCB, I haven't made any real progress.

Here's what happens... I plug the boards in, turn the machine on and I get nothing one the screen (monitor needs repair but I have it hooked into the RCA jacks on a TV right now). There is a small, very faint hum bar that moves through the screen, you can barely see it. But, the coin counter works.

But, after playing around earlier, I saw that if you hit the credit switch that hum bar gets a LOT brighter. But, if I unplug the coin counter, that doesn't happen. ... but I still get nothing on the screen (minus that faint humbar).

I have a steady 5V on the board, but with that said the ceramic resistor, big diodes in the bridge, and the regulator get hot... fast... ... very hot. I'm pretty sure that's not normal. The diodes have already been replaced with new ones that are good... so I doubt their an issue. I pulled and checked the regulator, it seems good. It's no grounding on the heatsink or anything like that.

Any ideas as to where I should start?
 
I pulled out the logic probe and hooked it to the board... before I even got started with anything I noticed that the probe was pulsing.

So I dusted off the o-scope and hooked it up to the 5V line. I get a .5V drop every 15ms... sometimes it drops a little more than .5V and when it does my probe starts going nuts again.

Ideas? Anyone?
 

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I pulled out the logic probe and hooked it to the board... before I even got started with anything I noticed that the probe was pulsing.

So I dusted off the o-scope and hooked it up to the 5V line. I get a .5V drop every 15ms... sometimes it drops a little more than .5V and when it does my probe starts going nuts again.

Ideas? Anyone?

check the regulator and the filter caps after the voltage regulator. Just for its and grins check the input to the 5 volt regulator.
 
Dang... that's where I was leaning with it.

I've checked voltage after the bridge (just before the regulator) and it's going in good... so I guess it'll be a recap and replace on the regulator and see what I get after that. :(

... while I'm ordering parts I might as well just go nuts and replace everything that even looks like it could be trouble.
 
Pulled the regulator and I can now apply +5 and GND from a switching power supply. With the regulator on there it would drag the +5 down to around 3V.

Anywho, board is still not working (surprise...) but I do get some squiggles and crap on the monitor... so that's better than just the humbar.

I'm looking down at the 74161 by the crystal and I'm getting nothing out of it. 3 of the 4 inputs are tied low, and the output of the one that isn't tied low isn't doing anything... It's just staying low. CLK on the chip is pulsing away but the output for that guy is staying low. /RESET is floating (as it's not connected to anything in the schematics), CE, CI, and /PRESET are all high... and if I read the right stuff on the chip... with those being high shouldn't that pin (13, QB) be doing something?
 
Yeah... that was part of the issue.

Board comes up now, paddle moves... but it seems to be starting a game automatically and the serve button doesn't work (but just stays lit all the time)... BUT, I finally have something to work with.

... now I need to order some 161's to replace the one that I had to pull off a spare Pole Position board. lol ... totally worth it though.

May the Woz be with me on this one.

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After letting it sit over night when I plug it in it goes to the attract mode screen (solid paddle along the bottom) but the ball isn't launching. And the score is 117.

When I coin the machine up, my start buttons light up correctly (P1 for 1 credit, P1/P2 for 2 credits). When I press the P1 Start button it goes into game mode and I get my paddle at the bottom of the screen, and the score resets to 000.

I can launch the ball if I press the launch button THEN short pins 12 and 13 on E1 (basically skipping that NOT). That will launch the ball but ONLY if I press the launch button first or while shorting those pins. Even then it launches the ball at the top of the screen and it works it's way down. After the ball goes down past the paddle it will launch from the correct spots (but only if still do that manual shorting).

Anything else I should look be looking at?
 
Good job on saving another classic. Its been a long, long time since I played one, but that serving delay sounds right to me. It seems like it was to keep you from knowing exactly when the ball was coming.

BTW I always sucked at the coin-op and yet I was pretty good on my Atari 800 computer version of it.
 
Just remember there is a differences between a a 74LS04 and a 74HC04 in some applications The HC series are not a good substitute for the older LS series.
 
Just remember there is a differences between a a 74LS04 and a 74HC04 in some applications The HC series are not a good substitute for the older LS series.

Yeah, I originally pulled the 04 that was on there and put a couple HC04's in the socket... wouldn't handle the CLOCK to /CLOCK... pulled an LS04 off of a Crazy Kong board, and she came right up again. ;)
 
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