Atari Canyon Bomber Restoration

No further work directly on the game. My basement workshop flooded a couple of weeks back and most of my free time goes to calculating how much new flooring to buy and to cleaning and reorganizing the space before I install it in another week or so. It needs done but its a frustrating distraction.

I did receive the TDA-1004A chips and I now suspect that the CB chips are/were in fact the 'A' version. I have a supply of the heat sinks and I picked up some silicon conductive pads I thought I'd try out. Current plan is to finish the basement, focus on my Drag Race cabinet and hardware work, then repair the CB and DR boards at the same time. The audio section is similar in both.

However, my supply of heat sinks is from donor boards where the audio section is either literally burned or shows signs of the TDA-1004 chips having been replaced. The problem is so common I'm extremely hesitant to just patch it back up. The image below is not my board but its not atypical. Id like to be able to leave the machine running for a couple of hours without fearing it'll catch on fire.

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I was thinking of asking for community brain power in sourceing a better heat sink, something like this maybe . I also tested out the TDA-2030 based two-channel amplifier I posted a picture of above and it works well. These run off ~ 12V and do 15 watts per channel. I need to document how many amps they pull on 4, 5 and 8 inch speakers but its very, very low. The form factor would work well for mounting and inserting into the circuit on boards of this design.

The CB will get fixed with the 1004A chips but for future restores, including the DR probably, Im going to be testing this out. The issue needs a better solution than the orginal design I think.
 
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

Call back on opening and reforming Cherry E68 switches. These are the E68-50A version which cant be found anymore. For this restore I resorted to modding some E68-00A buttons which are still in production or at least are still available. It worked out but required modifying the button cages.

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For my current restore I needed more of these and popped a poorly-performing one open. They are indeed glued at the bottom, not much glue but its there. And they are indeed a PITA if that tiny spring mechanism gets out of the casing, though I finally figured out the tooling combo needed to get them back together. So another future hurdle solved.

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First half of this year ended up dedicated to audio and other 'fix up the house' projects. The second half will be working on games. I've been quietly processing multiple cabs for powder coating and chroming. Mainly this was to have someone else deal with the sandblasting, leaving the 'funner' parts for me. We'll now see how fun it gets.

Anyway, when I left off on this a year ago :rolleyes: we had a good looking cabinet, solid video and game play but no sound ! The TDA-1004 amplifiers (one for each player) were clearly toast, as in magic smoke appearing when I applied power. No good images of the smoke but the chips looked like this:

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This is actually good condition as I've seen these amps burn through the board. @cwilkson was able to verify above that the un-obtainium TDA-1004 amps could be replaced with TDA-1004A, these obtainable from sketchy flea-bay dealers.

Over the last few days I rebuilt an Atari power brick with appropriate output voltages for CB. Transformer no. A006181-01, it has no F3, F4 or F5, just two fuses for the 120V power input. Power output is the same as the Type B Power Supply so an earlier progenitor? Anyway, the 'original' supply in the cabinet will need to be verified as to the audio power output ( pins 4-6). I remember not quite understanding what I was seeing as far as output; perhaps it was putting out too many volts thus the nuked caps and amps?

E-caps and new diodes for the audio power regulation were already done. The 'new' brick puts out ~ 26 volts which regulates down to ~17 on the board. Supply for the TDA-1004A ranges from 9 to 20 Volts and it puts out 10Watts @20V into 4 Ohms. Too much math for a Monday evening but the numbers are fine to power a 5" speaker apiece.

Rebuilt audio section with socketed TDA-1004As rocking new-style heatsinks.

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All sounds are working but White's engine sounds 'whiny'. Apparently, to derive a 'realistic car motor sound,' they used a complex method which takes a whole paragraph to describe in the service manual and which I will not be re-typing here. They generously list the exact timer, resistors and gates I need to check though. Hopefully it will be short work to find the problem.
 
This took a few minutes to work out this morning, these settings are scattered over several pages in the manual and the frequency adjustment trim resistors are only listed for the left channel.

Speaker volume and 'motor idle' trim pots interact, they need to be set at the same time. The whistle is pretty much independent.

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I'm sorry to hear about your flooding. That is hard, no matter what.
 
I'm sorry to hear about your flooding. That is hard, no matter what.
Yeah, that's fixed up now, that was actually last year. Micro-burst storm hit the west side of the house and the window wells werent covered and hadnt been cleaned in ever . I cleaned them and put acrylic covers on them, took several weeks to get around to re-doing the floors.

Brief scare with the original power brick I spent a lot of time rebuilding last year: No power at all to the audio channels ! Looks like I wired it wrong and blew both those fuses. Ok, I was \ am learning. New fuses and we're good to go.
 
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