Atari Video Music -- HELP!

[snesfreak]

Hi,

Picked up an Atari Video Music this weekend at a flea market for $20.

The unit powers on and appears to work OK, however, there is a lot of noise in the picture -- the objects flutter and jump a whole bunch, making it hard on the eyes, almost like something isn't connected right or a piece is broken. The RF switch is good, so it seems like it's an isssue with the timing or something like that.

I'm not real familiar with electronics, I've tried cleaning the potentiometers like I've gotten the flutter out of some 2600 paddles, but it's still doing the same thing.

I found some schematics at a AVM site, http://chucklarge.mine.nu/avm/ but I don't even know where to start looking!


Can any of you techi-geniuses out there lend me a hand?

[Mitch]

You aren't using an auto RF switch like the ones the came with the NES and every system since are you? They will give you problems like you described. You need an old style manual RF box, or an RCA to F-Jack adapter.
If you are already using a manual switch box then I have no idea.

Mitch

[snesfreak]

Mitch. Thanks for the reply. I'm using a standard RF switch, the one I use for my 2600.


I've considered replacing the potentiometers -- Radio Shack carries 100k Ohm ones for around three dollars so it might be a worthwhile investment to see what happens...

Is there anything else that can be easily replaceable?

This might be a dumb question, but are all of these units kind of hard to look at after some watching? Maybe I was expecting smoother graphics?

[jaegodylan]

Hello

I recently found an old Video Music. The problem is the power cord was literally chewed off! I found a photo of one and am looking for a modern replacement. Any clues?

Input 120 VAC 60 HZ 6W
output 16.6 VAC and 100 MA


Thanks!
Joe

[SleepyCow]

Hi guys, long time lurker, first time poster...

Wanted to shed some light on a few issues to be aware of...

First of all, the Atari Video Music units are *extremely* *rediculously* *very very* sensitive to static, and can be easilly damaged by even a slight charge from your fingers. So always wear a grounding strap when working on the unit, and NEVER EVER EVER connect or disconnect audio cables while the unit is plugged in and or powered on.

As to your noisy output issue, you are likely on the right track with the pots. Before attempting to replace them, try using an electronic cleaning solvent to try and bring the pots back to life.

Two other areas to examine closely:

Any electrolytic capacitors on the board may be dried out, burned out, or just aged. These are critical to the filtering of the power input as well as the audio and video signals. If these caps have gone bad, you can get snow-like noise, wavy lines, or pulsing. They should be fairly easy to replace and it is good preventative maintinance any case.

You should also try testing the unit with a modern high quality regulated switching power supply. IIRC, the original power supply is a simple linear unit, which after 30 years may not be working so great.

RE: The expected output, I think there are 16 possible output combinations with four 'shapes' and four 'patterns', all of which are, well, blocky. This is pre-VCS, non-microprocessor technology.

Good luck!