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Author Topic: Atari Breakout PCB repair. Work In Progress  (Read 7758 times)
smarty
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« on: November 29, 2016, 09:48:30 PM »


Part 1

So I was given this Breakout PCB earlier in the year and thought I'd fire it up and see if it worked.



First up the PCB was covered in lots of wires that were soldered onto the board but with nothing connected to them, some sort of previous mod that had been removed.



I de-soldered these wires and re-made a trace that had been cut on the PCB.

Visually there were a few IC's missing and one that was broken almost in half and partially de-soldered. After looking up the IC locations in the Ops manual, all three were 74LS08's, clearly someone needed them for something else! The solder pads were cleaned, new sockets fitted and IC's fitted.



Next up was the big filter Capacitor near the edge connector. This was clearly past its best so I replace it with another I had in my stash.



There were four wire links on the board which denote the game bonus given depending on score. These were a right mess where I guess they had previously been moved around. I removed the links and fitted a nice new 4-way dip switch block similar to what all the later Atari games have.



Next up it was time to make a basic loom to apply power and get some composite video out of the game.

Looking at the high level wiring diagram for the game, the power input comes from a 16.5Vac centre tapped transformer, which via a couple of diodes feeds the audio amplifier and then into an LM323 regulator which provides the regulated 5Vdc for the game logic.

From previous experience with these old Atari Black & White games I know you can happily run these games from a 12Vdc power supply as long as it supplies 3 Amps of current if the have an LM323 regulator.. Most JAMMA switcher supplies wont work as they don't provide enough current on the 12V rail. With power connections made to an edge connector I looked up the pins for the Video output and it's ground connection and wired these to a phono (RCA) connector which would plug into my video monitor.

With only these connections made I should be able to see if the board is dead or alive, or somewhere in between.

One final check I decided to make was to confirm that the 5V rail and the Ground rail on the PCB were not shorted to each other, this was confirmed as being OK with my Multi-meter set on continuity test.

Time to fire it up!

So with monitor connected to the video cable and the edge connector plugged into the PCB I powered it up...



Not bad... The board has a video output, which is stable apart from some image tearing on the right hand side, I'll need to confirm if this is a fault with the PCB or if my monitor is struggling to sync to the signal.

You can see the score numbering along with the numbers indicating which player is 'up' and which ball is is in play. There are clearly not correct, but the fact they're being show is a good sign.

There's no playfield of bricks, a players paddle or any balls flying around the screen so the board at this point so I need to investigate further to see whats going on.




So next up I need to make connections for controls, and coins switches etc, then I'll print the schematics and get out my trusty Logic probe.

To be continued...  Smiley
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Andreas_AUT
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« Reply #1 on: November 30, 2016, 06:14:23 PM »

Nice repair log !
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Pinge
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« Reply #2 on: November 30, 2016, 06:18:50 PM »

Nice, I will follow this, have to learn how to use a logic probe for my super-breakout pcb:s...
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smarty
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« Reply #3 on: December 03, 2016, 09:55:17 AM »

Atari Breakout PCB repair. W.I.P Part 2

Part 2

Following on from my last session looking at the Breakout PCB, I spent a short while making the wiring connection more complete on the edge connector. I added Coin 1, 1 Player start, Serve and the paddle control. I also added a link to the edge connector for Coin 2; on these early games the coin switches use a common connection along with a normally open and a normally closed contact. If the normally closed contact connection of Coin2 isn't connected to the games common ground connection the game will always think the in Coin2 switch is being activated and stuck on usually stopping you from coining the coining up properly or playing the game correctly.



I decided to begin this session by checking all the the H & V clock signals that are divided down from the master clock circuit on the PCB. They all appear correct and present when using a logic probe to check for signals at the IC's where they are created (K1,L1,N1,N1 9316 IC's).

Next up I look at one of the Rams at L3 just checking for signals, no real idea of thinking about a fix just checking components that could lead to finding a fault; well its missing one of the Chip Enable signals on pin 3, not a high signal, not a low, nothing. Taking a look at the board (even though I already made a quick visual check) it's clear there's a broken trace, most likely from the original multiple wire mod that had been installed at some point.

Image below shows the offending broken trace.  



I checked where this was wired and sure enough one side of the broken trace was connected to pin 3 of the IC that had the missing signal.

I made a repair using an old cut off capacitor leg. shown below.



Powering up the game I'm now presented with some Playfield bricks Smiley



So in my mind now other than the bad video syncing/tearing issue, the game when in attract mode is missing a bouncing ball along with a paddle 'wall' which should completely cover the bottom part of the screen in attract mode. There is a 74157 IC which controls these component parts of the video graphics, before they are joined to a resistor network to make the final video signal.
The  *Pad signal is missing, again using a bright light to investigate another trace is broken (to the left of the middle IC in the photo below)



Once this is repaired we appear to have a paddle at the bottom of the screen, not completely covering the horizontal plane but good enough for now until I have fixed the bad syncing if the video.



I thought I'd try and find why the ball was not visible, it should be bouncing around the screen in attract mode. There is a signal called 'BALL' this was active, it passed through a circuit linked to the serve button on the control panel and the signal turns into 'BALLL DISPLAY' this signal is stuck low.

Tracing though this part of the circuit I find the 'Serve' signal (derived from the control panel button) is constantly stuck low even when the switch isn't connected, the signal should be 'high' when the serve switch is 'open'.

More signal tracing goes on which leads to a 7432 at location D2 looking at the image below you can see the area around pin 12 look a bit brown and burnt. It turns out pins12 a logic input is directly shorted to pin 11 an input. Also the track in between pins 11 & 12 was shorted to these two pins! That trace is a signal connected to the coin switch circuit. Considering pin 12 is connected to the serve switch I can only guess that at some point someone has put voltage down this connection instead of the serve switch wiring.



I decide to chop this pin out to see what's going on with the burnt looks around this IC. After snipping the leg off, I'm greeted with the following mess! This IC has failed big time with parts of it melting to the track below the IC.



This area needs to be cleaned up and checked over before replacing the IC and hopefully seeing the Ball bouncing around the screen.

To Be Continued...
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anunaki
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« Reply #4 on: December 03, 2016, 10:20:53 AM »

I enjoy these kind of topics a lot. Thanks for sharing
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xadhoom
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« Reply #5 on: December 03, 2016, 10:53:31 AM »

You can use LM323K Replacement Switching Regulator 5V 3A
It works like a charm
http://www.ezsbc.com/index.php/psu5.html
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smarty
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« Reply #6 on: December 03, 2016, 05:03:31 PM »

Interesting replacement for the regulator, I may buy a few of those. Thanks.

I spent a bit more time this afternoon looking at the game.

Part 3

So cleaning the are around the IC that had failed showed no real track damage, the board is burnt and doesn't look pretty but nothing is shorting together or in need of repair.



I fitted a new socket and replaced the 7432. Upon powering the game up the video tearing I was previously seeing has gone there's still some sort of image issue on the left side, and the bouncing ball has appeared. Progress is being made. Smiley

The ball was just running from the bottom of the display to the top and repeating over and over. No collision detection or rebounding with the bricks or side walls.



Now then, the paddle wasn't looking correct, It would change size when you turn the spinner but didn't really move correctly. In the paddle circuit I found a 7408 that had a bad output on pin 11. This was swapped out with a replacement and as shown below the paddle now works correctly, even though it is too small. The ball will now rebound off the paddle in game mode or in attract mode, it will also rebound off the top wall above the score line so it's not detecting the bricks.



Clearly there are issues with the game coming in & out of attract mode, the scoring isn't working correctly and I'm sure the amount of live isn't being counted correctly and I haven't even looked at the sound circuits yet.

There's still plenty more to fix by the looks of it. I'll keep you all updated.
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« Reply #7 on: December 06, 2016, 05:38:20 PM »

 Space Ace
thanks for sharing
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ckong
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« Reply #8 on: December 07, 2016, 04:23:38 PM »

Very nice topic.  Smiley
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Muerto
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« Reply #9 on: December 07, 2016, 05:30:28 PM »

Great topic! and very nice macro images!!
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Franzy21
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« Reply #10 on: December 22, 2016, 10:01:57 PM »

Excellent.
I love it.
When is the next episode?
 Grin
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Lonewolf
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« Reply #11 on: February 14, 2017, 10:14:04 AM »

Hello. Can you give me details on your test monitor and video wiring please
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vernimark
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« Reply #12 on: February 14, 2017, 12:35:16 PM »

I agree, great topic!
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smarty
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« Reply #13 on: February 15, 2017, 08:19:32 PM »

I will make a diagram over the weekend of exactly how I have this connected up.

The repair is slightly on hold at the moment as I have a few other projects which take priority.
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rogerxy
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« Reply #14 on: February 16, 2017, 08:36:14 AM »

Very interesting post  Smiley
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