Atari 5200 problem -- crackling, static sound?

[Gapporin]

Hello, everybody. I'm a long time listener, first time caller (or third time caller, I guess, if you look at my post count). I wasn't sure whether to put this in the 5200 forum or the Hardware forum, so please forgive me if I chose the wrong spot.

 

After finally collecting together all the needed parts for my Atari 5200, I plugged it in for the first time the other day. I put the RF lead in my regular switchbox, and the power adaptor into the Atari itself (it's a two-port model, so it doesn't need the proprietary switchbox). Turned it on, and...was greeted by a loud static noise. Picture looks fine, but there is no [normal] sound coming out at all, just a loud "crackling" noise. I can wiggle the RF lead and the switchbox around to make it softer, but I can't get rid of it as a whole and I can't hear the actual sounds, either.

 

I took apart the system and sprayed the insides thoroughly with canned air. I found where the RF lead was connected, and replaced it with a known working lead. I even removed the RF shielding from the system, thinking that might be involved somehow. No dice. I get the same results -- a more or less good picture, but unbearable static for sound. I even tested the RF lead that was originally in the Atari that I thought was "bad" and it works fine with my other consoles.

 

At this point, I'm stumped. I've not familiarized myself with the 5200 long enough to know of any other solutions. Does anybody have any ideas as to what the problem might be? Thanks in advance!

[classics]

Are you sure you have the correct power supply?

 

What are the markings on the brick?

 

Steve

[Gapporin]

It's got an Atari logo on the back, followed by:

 

"AC/DC Power Adaptor

 

Part No.: C018187

Input: 120VAC 60Hz 38VA

Output: 11.5VDC AT 1.95A"

[+FujiSkunk]

Is the crackling sound coming from the system or the TV? If it's the TV, it may just be simple RF interference. Playing with your TV's fine-tuning control might help.

Edited August 15, 2008 by skunkworx

[+Mitch]

You may need to adjust the audio frequency. There should be a tall red thing on the 5200 system board that can be adjusted with a hex wrench. Using a plastic hex wrench is highly recommended.

 

Mitch

[classics]

Power supply is correct.

 

Steve

[Gapporin]

None of those ideas seemed to work. Sorry! :/

 

I really do think it's a problem with the 5200 more than it is my TV. All my other RF-based systems work just fine with the setup I've got.

[classics]

Sound in the 5200 is produced by the Pokey chip. Try swapping it out with one from an 8-bit computer, another 5200, or a 7800 Ballblazer cartridge.

 

Steve

[classics]

Actually, if you just remove pokey from its socket, bend up pin 37 and put it back in its socket, you should be able to tell if its a bad chip or not. If you get no static with pin 37 out of the socket, then the static is coming from inside Pokey. If you still get static with the pin out of the socket, its coming from the RF section.

 

Steve