Asteroids repair

g2nickk0

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I recently picked up a '79 Asteroids cabinet that I was going to make into a custom MAME type project. However, after some reading and learning I've decided that tearing this beautiful machine apart would be a tragedy! I have a background in repair and servicing HVAC equipment and appliances. And a love of electronics projects. I am beyond excited to dive into repairing this arcade cabinet and imagine this will not be the first for me.

I bought the cabinet as non-working. The guy I bought it from said he had swapped in a working Lunar Landing board and everything worked fine, so that leaves me with a PCB that needs some love. Here is a video of what it does when you turn it on: https://www.youtube.com/watch?v=7ml4XKCX9Mo&feature=youtu.be

Any advice for a beginner would be awesome. I do have a logic probe and multimeter. I've read the beginners guide and watched some videos. I'm just excited to learn arcade cabinet repairs.
 
Get a cap kit for the asteriods pcb.
Does the asteriods games coin up meaning did you pull down the coin switch and did the game make a coin up sound?
Did you press player on button?

Here what i would do while waitng for the cap kit..
With the power off...

Clean the edge connector. A pink eraser will clean the edge connector.
Reseeat the rom chips and see if the pcb changes..
 
The red (spot killer) light flickering on the monitor is "BAD".
If you continue to have the monitor plugged in with the "BAD" logic board then soon you'll have to repair both the logic board AND the monitor. :(

Test all voltages on the logic board.
Put in TEST mode and listen for beeps.
Clean all connections.
Keep the monitor disconnected for now.
READ - there are many threads and URLs about fixing Asteroids.
 
I had to read the manual to fix mine started out with a AR board dead no power . Recap it got the power back , still had a issue recap board and monitor , was still nothing working then I found out that the ram was bad .
 
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if you need cap kits or parts for anything i have them in stock along with full rebuild kits for the AR boards, big blues, etc. let me know if you have any questions with parts.
 
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Recapping the game PCB is not really needed unless one of the caps is actually bad. That is rare because they are not subject to anywhere near the heat and voltage of those on the monitor boards, and also because they are typically rated at 25v or even 50v and the PCB operates well below that at 5v.

On the other hand, they are 38 years old and parts of the PCB do operate closer to the rated voltages of the caps (notably the +22v and -22v going past the larger 470uF caps).

On the other hand, the symptoms shown in the video are not caused by bad caps on the PCB.

The rapid blinking of the image but more importantly the P1 and P2 start buttons means the PCB is in a reset loop. This is caused by its inability to execute the game code. That might mean it cannot access the game code (clean the legs of the four ROM chips) or that the RAM it needs as workspace is bad (run self-test to check) or that a fault on the vector side of the board is not giving it a chance (insert complex troubleshooting here).

You can verify this by probing pin 40 of the CPU (the reset pin) which you will find pulsing. In normal operation it will be low at power up but then go to a steady high state.

I agree with all of VectorCollector's steps, and the order in which he lists them, Including the first one of disconnecting the 12 pin Molex connector going to the monitor. There are labeled test points for voltages on the PCB. Beeps upon power up with the test switch on will indicate RAM problems (or no beeps = all good RAM). Next steps depend on data from these steps.
 
Get a cap kit for the asteriods pcb.
Does the asteriods games coin up meaning did you pull down the coin switch and did the game make a coin up sound?
Did you press player on button?

Here what i would do while waitng for the cap kit..
With the power off...

Clean the edge connector. A pink eraser will clean the edge connector.
Reseeat the rom chips and see if the pcb changes..

I'm not sure what you mean by coin switch... But I've tried inserting a quarter and pressing any and all buttons. The kill switches on both the back of the cabinet and coin door are pulled out while testing.

I've cleaned all the connections with an eraser, dusted off the board, and pulled out the socketed chips out and cleaned up the connectors and reinserted.

Any recommended resources for buying the cap kit?
 
The red (spot killer) light flickering on the monitor is "BAD".
If you continue to have the monitor plugged in with the "BAD" logic board then soon you'll have to repair both the logic board AND the monitor. :(

Test all voltages on the logic board.
Put in TEST mode and listen for beeps.
Clean all connections.
Keep the monitor disconnected for now.
READ - there are many threads and URLs about fixing Asteroids.


Great info, thank you for saving me from blowing my monitor!

I'm going to start testing with the logic board. But I have a question about TEST mode. When I put it in test mode a single dot or a 1 inch vertical bar shows on the monitor and I get a once a second popping/pow type sound. Wouldn't call it a beep..... Is that an indicator of something I should focus on?
 
Read the troubleshooting guide in the manual. (see links in link below)

http://arcarc.xmission.com/Tech/Asteroid Tech/asteroidsrepair.html

>> read advice from douglasgb
>> voltage and clocks first
>> visual inspection of broken traces, bad parts etc
>> use eprom programmer to check roms
>> swap out 6502 perhaps
>> ohm out sockets (or replace suspected "bad ones" if you are skilled at soldering)
>> get test mode working

Got a logic probe?
Got a scope?
Must have a DVM.
>> makes debuggin' the logic board much easier ;)
 
Tonight's progress:
Disconnected monitor plug
Confirmed power brick is outputting voltages within specs according to the diagram.
Attempted to probe pin 40 and got stuck...
Do I use TTL or CMOS logic setting?
Which pin is pin 40? The schematic doesn't help me to identify which pin it is.
When you say logic board, is that the main PCB?
I have a meter and a logic probe. No scope....a bit on the expensive side for just getting into this.

Sorry if these are some newb questions but I need to get the basics down to fully understand moving forward :D
 

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Dude ...

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BTW, you need to verify the DC voltages ON the logic PCB and not necessarily just at the power brick or the ARI.

Set logic probe to TTL.

Keep going and learn ... but ultimately, you might have to send the board out for repair.
 
Keep going and learn ... but ultimately, you might have to send the board out for repair.

I'm still plugging away and I think learning some things but also becoming frustrated in the process.

Probed pin 40 with logic probe, definitely pulsing.

On AR board test points getting 5.3vdc (+5v reg test point) and 11.69vdc(+10.3 unreg test points(which I believe is fine since unregulated))

SPKR1 and 2 getting 6.1vdc. Schematic doesn't tell me what voltage should be here, but simply that it is a test point, so I'm not sure if that is correct or not, but I'm not too worried about sound at this point....

To be sure I also back-probed the molex plug to eliminate a failed connection. So I believe this narrows it down to being a PCB problem for sure.

The beeping RAM test has me a bit confused, because I get a pow pow pow type sound in test mode but I'm not sure if it could be considered a beep. Also I noticed I get a what I think is a possible actual game sound effect. Heres a short video of it: https://youtu.be/3PFCCTtcn_g

Ignore the clicking in background, its just my water softner. Also ignore the mismatched socks and pajama pants.

As always thank you for any help you can provide!
 
I recall there being a leg on an IC that you can cut that effectively isolates the "game" side of the board from the "Vector generator" side of the board. If you do this and the game comes up and plays blind (meaning it has no picture) then all your RAM, ROM and cpu stuff is fine. If it still resets then you need to fix that before you can move onto the AVG (Analog Vector Generator).

I want to say it was a 74LS42 and you had to cut pin 1.

DONT DO THIS IF YOU THINK YOU MAY NOT BE ABLE TO REPAIR THE CUT PIN!!!!
 
found it. Not sure if its a LS42 or not though.

cut pin 1 of L6 (DMAGO) which isolates the Vector Generator
 
Inability to run self test means bad ROM or bad CPU.

That is where I will start, especially since they are socketed. Correct me if I am wrong with my understanding, but the CPU is a bit universal in the sense that I can buy an "off the shelf" 6502A with no special setup required.

Now the ROM chips are programmed for the specific game, if I'm understanding this correctly. So I'd need the chip plus would need to burn/install the information onto the rom using an eprom reader. Other than trying to do that myself, where can I buy a already programmed ROM chip?
 
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