Atari Canyon Bomber Restoration

I left the PCB running for hours in attract mode last night & the house didn't burn down so I presumed everything past C35 wasn't doing any harm. Cleaned the legs on the original resistor and reinstalled. Installed one of these in place of the LM323 regulator as I had it on hand. PCB now works on power from the original power supply. Voltage is 10.03 at the edge connector, 5.19 following the space-heater resistor, and 5.16 at the far end of the board.

I'm assuming the gunk on the original resistor was preventing power flow from my DC power supply from getting into the board, accounting for the voltage drop I was measuring, and that he LM323 was bad or shorted somehow, causing issues when feeding it with the OEM power supply. Will leave it running and wire up controllers to test out sound and gameplay.

The wire wound resistor put off a lot of smoke, presumably burning off dust I hadn't completely cleared out of it. Its still pretty hot. Any value in replacing with a newer resistor type with a higher wattage rating?
A higher wattage rating won't reduce the heat.

The heat is given off by the resistor, which is acting as a voltage divider in a network.

P (power dissipated) = V^2 (voltage squared) ÷ R (resistance)

Measure your voltage drop across the resistor, and plug in the formula. You'll see changing the rating higher won't affect the power - the key factors are resistance and voltage drop.

Or if you know the current through the resistor, you can use this formula:

P (power dissipated) = I^2 (current) × R (resistance)
 
Before

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After

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The volcanos polished up nicely. Still hope to do a thorough paint job on this in the future.

Fun Fact: Canyon Bomber calls for Cherry E68-50A push buttons in those metal cages under the big round buttons. The '50A' has a distinctly different actuator and movement profile compared to the versions available these days, to the point that the common 00A version doesn't work here without modifying both the actuator and cages slightly.

Button Profiles.jpg
The '50A' version doesn't seem to be available anywhere of course, and I suspect this will be the same in other games by Atari and Kee of this era, several of which I have coming up to work on. :( I will try out the 40A version ( a few are still out there) and report back once I stock up.
 
I'm aligned with what you said, except if the resistor corroded into the solder joint, you could be taking a voltage drop before the resistor.

I assume you have one of these that you can benchmark, but if that resistor is dropping voltage, it will get hot. It's just the science of it. The power is dissipated as heat.

Nope. Not talking about that. I'm talking about cross-board IR drop on the +5V rail(s).
Neither the LM323 not its power assist resistor has anything to do with that.
It's simply the resistance of the traces on the board times the current flowing through them that causes that drop.

I don't have a cabinet and my PCB isn't checked out and I don't have the time to do that anyway.
But as @thegleek said....

it's not rocket science ffs.

It's a linear supply. And a simple one at that. You can spitball the values and be damned close to reality.
If I survive to the weekend, may I can do a write up.

Actually, I'll do it right now.
Neglecting the variance in line voltage and the waveform and component tolerances and assuming the PCB is drawing 3.15 ADC....

You get 120 VAC from the wall.
That's dropped to 8.25 VAC by the transformer. (16.5 VAC - center tapped)
The peak voltage of the transformer output is 11.67 V....unloaded.
Loaded with half of 3.15 amps (DC) at a pretty small duty cycle (about 20A peak current) maybe that drops to 11.5 VAC.
At 20 amps the diode drops maybe 0.9 V to charge the BFC to to 10.6 V (peak).
It's probably discharging for about 6-7ms. (too lazy to solve equations)
A 3.15 amps, the BFC voltage should sag about 0.7-0.8V.
So it should drop to about 9.9 V.
Assuming a piecewise linear waveform (a good assumption!) , the average BFC voltage should be 10.25 VDC.

Now, assuming the LM323 is doing its job, the output voltage is 5.00 VDC.
The 2 ohm resistor sees (on average) 10.25 V - 5.00 V = 5.25 V across it.
So it provides 2.625 amps to the 5V rail and it dissipates I^2 * R = 13.8 W.
The LM323 has to make up the difference.
It supplies 3.15 A - 2.625 A = 0.525 A to the 5V rail...on average.
In the instantaneous extremes the LM323 will supply 350-700 mA.

That's how it works. The exact measured numbers will be verry close to these.

This weekend I'll try to have a live call with @greedycrisp to figure out what's going on.

Meanwhile, he has a thing that works. So that's good.
 
Before

View attachment 750243View attachment 750244

After

View attachment 750245View attachment 750246


The volcanos polished up nicely. Still hope to do a thorough paint job on this in the future.

Fun Fact: Canyon Bomber calls for Cherry E68-50A push buttons in those metal cages under the big round buttons. The '50A' has a distinctly different actuator and movement profile compared to the versions available these days, to the point that the common 00A version doesn't work here without modifying both the actuator and cages slightly.

View attachment 750250
The '50A' version doesn't seem to be available anywhere of course, and I suspect this will be the same in other games by Atari and Kee of this era, several of which I have coming up to work on. :( I will try out the 40A version ( a few are still out there) and report back once I stock up.

Interesting that those metal button frames look like inverted Nintendo joystick frames.

I've had a lot of luck disassembling and cleaning/repairing old components like volume pots/switches. But beyond that, I suspect that those old interlock switches still use the same innards as the old so you could swap the push pin over to a new assembly or possibly move the contacts/springs to the old setup. Assuming you have the old switches that is.
 
But beyond that, I suspect that those old interlock switches still use the same innards as the old so you could swap the push pin over to a new assembly or possibly move the contacts/springs to the old setup. Assuming you have the old switches that is.

I do have the original switches but don't see a way to open them without irreversible destruction, they're either glued or heated during production to make the plastic halves inseparable. And after seeing this diagram I presumed the best I could do was to have tiny springs shooting off all over the room anyways.

1718885629180.png

My modifications are pretty simple.

1) Shape actuator of new switch with a vibrating knife so it matches the '50A' profile. Basically this just stops the button from revolving, I might skip it if I do these in the future.

2) Shim the cage halves apart with a 0.06" strip of metal. This expands the cage bottom the same distance away from the control panel, which in turn allows for the button to be 'open' when at rest. Without the shim the switch is 'closed' without even pressing the button. I tried continually shortening the actuator but eventually the back of the button was whacking on the cage due to the overtravel.

I ordered some 40A buttons which have the shorter overtravel, I think they may be a better solution. Perhaps insert a small screw in the top of the actuator, allowing easy adjustment of button pressure.

All of this is massive overthinking and engineering on my part anyways.
 
I do have the original switches but don't see a way to open them without irreversible destruction, they're either glued or heated during production to make the plastic halves inseparable. And after seeing this diagram I presumed the best I could do was to have tiny springs shooting off all over the room anyways.

Don't have any in front of me but glue/heat would be an extra MFG step and increase cost. I can't recall COTS switches where they bother with that. I'm sure it's just a tight plastic snap fit. At any rate, any leftover interlock is going to be the same and Atari used them in droves so just pull a spare that if it gets broken it's not important.

YMMV
 
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@cwilkson , yes, the area was still wet. Just very happy to have the area done so I snapped the pic.

New speakers installed, coin door and speaker plate attached, one side has T molding installed. Pushing to get a lot completed this weekend. I think all the parts are ready to go.

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Completed T molding installation using Rotheblog 3/4 Atari flat molding. This machine uses quite a bit of it. Installing it between the top and bottom sections of the cab required use of a floor pull bar.

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Installed locks on front and back, had to bend the pawl into shape.

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Original tube from the missing TEC monitor was swapped to an M7000 a while back in the process. I installed the monitor.

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Installed the PCB cage, PCB, IR filter board, power supply, back door cutout switch, test switch behind coin door. Built / installed a new power cable.

Initial testing indicates something is miswired in the power switch circuit ( i.e., the power brick works when jumped on but not behind the switch wiring) and possibly elsewhere. No idea if it's my repairs or if it was configured wrong before. Who knows the last time this thing was working.

Was going to troubleshoot this morning but decided to take the day off instead. C'est la vie.
 
It's a linear supply. And a simple one at that. You can spitball the values and be damned close to reality.
If I survive to the weekend, may I can do a write up.

Actually, I'll do it right now.
[SNIP]

I just reread that post and realized it might come off as abrasive. That was not my intent.
I was in a hurry to post while I had a real computer with a real keyboard and I had to finish ASAP before sprinting to my baseball game.
So yeah....terse but not angry. Carry on! :)
 
Getting back to this today.

Power switch circuit resolved. One wire crossed, a couple of the .084 connectors on the brick needed readjusting. Have line power to monitor and marquee, now to trace the PCB harness.
 
Main harness is traced and correct. Powering up game produces lights in marquee and control panel, neck glow on monitor, no gameplay, no sound

Power at board is 12.3 VDC, 26.5 VAC at the correct places, 6.92 V at control panel.

Taking the board back to the test bench to make sure its still good, will put a TPG on monitor.
 
Power at board is 12.3 VDC, 26.5 VAC at the correct places, 6.92 V at control panel.
12.3 VDC is too much. Like your board is open circuit. Is your +5 V still good?

With PCB powered by the cabinet measure both ends of your power resistor.
You ahould get approximately 10.3 VDC (unregulated) at the input end and 5.0 VDC (regulated) at the output end in an original system.

BUT….
You redesigned your power supply.
So all bets are off.

-IF- the replacement regulator is working you might get less input current than you're supposed to. So the transformer output will be higher. And your power resistor will work harder.

No that doesn't make sense. The math wouldn't work. Your +5V rail is either too high (oh no!) or it's zero.

I think you have to have an open circuit.
Measure the resistor voltages and report back.
 
I'm pretty sure now the power issue was a red herring. I traced every wire in the cab but found only a single issue with the power switch. I looked at the 'new' connector I installed (below) and decided some wires might not be touching the board. So I re-did it again.

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Board now works in the cab, game plays successfully. However, no sound. Not entirely a surprise, Id never tested it and suspected I'd have to get to it.

I spent yesterday building a full test harness so I can troubleshoot sound on the test bench with the game running. Going to troubleshoot as much as I can today.
 
Taking a small victory lap on this one ( though a few odds and ends remain, more on that later...)

Atari Canyon Bomber, serial # CB-1332. Everything still original except that missing monitor chassis and the back panel \ doors.

Much thanks to @maberle @hisnice @cwilkson @lilypad19 @ArcadeTechGW and others for assistance with this one.

01.jpg02.jpg
 
List of stuff I've done that I remember

Power brick ( Atari style B)
- Clean or replace all connections
- Replace two broken fuse holders
- New Big Blue Capacitor

Monitor
- Locate, clean, and re-cap a M7000 monitor
- Tube swap original TEC-623 tube & yoke
- Build new cardboard bezel
- Clean and polish original Plexi screen cover and Plexi bezel

PCB
- Socket and replace failed RAM
- Track down and repair trace shorts from same
- Socket and replace couple of flip-flops
- Replace voltage regulator to repair 5V power
- Replace cracked connector on RF shield
- Audio amp work (ongoing)

Wiring Harness
- Replace most connectors due to corrosion

Coin Door
- Replace missing coin mech
- Replace missing light
- Rewire and replace coin switches
- Powder coat AND paint
- Re-chrome Owl Eyes and coin returns

Control Panel
- Strip and clean metal button frames
- Replace broken button aprons with NOS
- Replace button mechanicals, clean and polish buttons
- Clean and polish Volcanos
- Update wiring connectors

Cabinet
- Repair broken panels
- Polish\varnish panels
- New laminate on front
- Replace missing back door and panel
- New heavy-duty feet
- New T-Molding
- Speaker grill painted
- Bezel holders powder coated & painted

Misc
- Clean & Polish coin bucket
- Clean & Repaint light fixture
- Clean and re-oxidize original bolts
- New speakers
- New power, test, and cut-out switches
- New power cable
 
Brilliant. Great thread, great restore, great game. One of the coolest art packages of the vintage Atari era.
 
Door and upper back panel were missing

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TEC-623 monitor chassis was just gone... Tube was still there, swapped it into an M7000, the other OEM model for this game

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I never bothered to test the power supply as it was, just refurbed it

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Kept the original coin door, still has security bar holes though

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