Think you might have a 'hokey' POKEY?

[TheRealAnubis]

Hi,

 

Just a quick note in case this helps anyone -

 

I have a couple of 5200's (2 port) in need of repair, and both of them have extremely faint sound. If you crank the volume waaaay up you can just barely hear the sounds. I thought it was strange that both of these units could have a dead POKEY, so instead of trying to locate a cartridge (then desolder, then clean up the pins, then install in 5200), I decided to pop out the POKEY's and test them in my Atari 800XL.

 

PLEASE make sure that you get the right IC for your motherboard! I'm not sure if Atari did any revisions and moved things around or not... This goes for the 800XL as well!

 

First, the POKEY in my 2 port 5200 was the large IC in the lower left of the motherboard (when the joystick ports are facing you).

 

The label on the 5200 motherboard reads 'A7', and the chip has the number '12294' on it. I'm not sure why the labels are so fuzzy - they look great at 200%! Anyway, you get the idea.

 

 

On the Atari 800XL, the POKEY is 'U22' on the motherboard.

 

 

Pop the POKEY out of your 5200 and swap it with the one in your Atari 800XL, then hold down the 'option' key on the right hand row of buttons while powering on. When you see the blue screen, release the button. The self test options will come up, and then you can use the 'select' button to go to the 'Audio-Visual' test, then hit 'start'. The test will play a simple tune on all 4 voices. If it sounds good, I'm betting your POKEY is fine - look at the Axial Poly capacitors (C13 & C14) 820Pf 25V - in your 5200, as these are prone to failure.

 

 

I just ordered some from Mouser - I could only find 50V, but the voltage rating on caps can always be larger than the original value, you just have to match the farad rating exactly.

 

Search - 23PS182 - they are 25 cents each. I'd replace both of them at once.

 

If anyone has anything to add, or if you find a mistake, please let me know!

Edited June 27, 2014 by TheRealAnubis

[Lynxpro]

Might want to rephrase that. People are calling an FPGA emulating a POKEY a HOKEY.

[TheRealAnubis]

Might want to rephrase that. People are calling an FPGA emulating a POKEY a HOKEY.

 

Really? HAHAHAHAHA! That's pretty funny!

[valthonis]

I replaced the caps with a pair of these (http://console5.com/store/820pf-50v-polystyrene-film-capacitor.html) as I was getting no sound. But even after replacing the caps I still have no sound.

Any suggestions of what else it could be?

 

Thanks!

[TheRealAnubis]

I replaced the caps with a pair of these (http://console5.com/store/820pf-50v-polystyrene-film-capacitor.html) as I was getting no sound. But even after replacing the caps I still have no sound.

Any suggestions of what else it could be?

 

Thanks!

 

Those look like the right ones.. Have you swapped the POKEY out to see if that's a problem? Also, try (gently) removing and then replacing the POKEY - sometimes they get corroded a bit and don't connect well.

[valthonis]

 

Those look like the right ones.. Have you swapped the POKEY out to see if that's a problem? Also, try (gently) removing and then replacing the POKEY - sometimes they get corroded a bit and don't connect well.

 

Pull it out and plugged it back in, sadly no difference. I cranked my audio on the tv way up, not even the fainted sound from the game.

Well that's assuming Dig Dug or Qix should play something even in demo mode (no working controllers yet).

 

 

---Going to start a new thread as there appears to be additional problems with my 5200.

Edited July 16, 2014 by valthonis

[TheRealAnubis]

That got me as well... None of the 10 or so games that I had made a sound until you hit start! You may be fine! Let me know what happens once you get a working controller hooked up..

I thought that it was strange that they were all so quiet, but this being my first 5200, I didn't know.

Edited July 16, 2014 by TheRealAnubis