My Missile Command has no sound

smalltownguy2

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Picked up a very nice Missile Command this week, but it has no sound. Need some help here. Here's what I've done already:


  • Verified all wires to the speaker are all connected.
  • Tested and replaced the ARII board with a known working replacement
  • Tested the volume pot
  • listened to the speaker on full blast, just a hum that gets louder as you turn up the pot
  • cleaned the edge connector on the board with a pencil eraser and re-seated it.
  • removed and re-seated all socketed rom chips on the game pcb
What next?
 
Go buy an Atari 7800 Ballblazer cart or pick up an old Atari 5200 off of Craigslist for parts. :) There you will find a POKEY chip.

Only if you enjoy desoldering 40-pin devices. :) Or spend the extra $3-$4 bucks and buy a new one.
 
Bad LM324 op-amp on the board. I don't have the exact location but I think it's in the 10th or 11th row.
 
Here's what the original owner of the game told me when I bought it:

"This game does work, but probably 13 years ago the sounds started getting crackly sounding. I seem to remember disconnecting it, but maybe we just turned it down... either way, there is no sound now.
"

Does that hep shed any light on the situation?
 
Bad LM324

345678

Here's what the original owner of the game told me when I bought it:

"This game does work, but probably 13 years ago the sounds started getting crackly sounding. I seem to remember disconnecting it, but maybe we just turned it down... either way, there is no sound now.
"

Does that hep shed any light on the situation?
 
You're probably right on the 5200 pokey being socketed, but I'll pay more in shipping for a 5200 than I will for a Ballblazer cartridge. In the end, I spend more moeny (in shipping) for a socketed chip, or spend more time desoldering one from a cartridge.

As it seems, bit_slicer seems to think it's something else...
 
If you have access to a simple audio probe or to an oscilloscope you can make quick work of isolating it.

Also, you may be able to use a logic probe that has audio beeps to listen to the audio as it comes out of the digital portion of the circuitry (pokey) and on to the op amps and other analog components. I've done that many times to isolate where audio issues are on boards. It sounds really screwing coming from the little beeper but you can make out audio noise. :)

Also, for 5200s, just check your local Craigslist and for cartridges check the used game stores.
 
Well I was thinking if he had another Atari game he could just swap pokeys to check real quick to eliminate that chip pretty easy.
 
I do have access to a Centipede, but it's on location, so I'll have to wait until after hours to grab the board. Maybe I'll do that tomorrow night.
 
Swapped pokeys, no dice. Then I looked to the LM324. Now mind you, I haven't ever done an IC removal before.

Survey says.....










































We've got SOUND! Sweet! I fixed my own board!! WOOT!
 
Yeah, thanks for the help (and hardware!), bit_slicer. I really appreciate it. Let me know if there's anything else I can do to return the favor.

Pics coming tonight...

No sweat! Pics would be a great way to return the favor. :cool:
 
I call the LM324s "three to fours" because you'll be replacing three to four of them while repairing boards that have them. :)

Bill
 
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