16 replies to this topic

[A-T-A-R-I]

Hi all,
As you all know, I am always having problems with my units. I haven't got around to fixing my sixer yet, so I popped out one of my 4 switchers. Turned it on and all is working ok, but it seems like some rf or something is coming in on the screen. I tried taking a picture, but it doesn't show up too well.

It is hard to explain, looks like if you had the screen under water and was looking down thru it while the water was moving a little. So, I thought I would open it up and tinker. So far, I changed the power regulator, that green thing next to it, the grey tube thing right above it, and also reflowed the board. Also changed the cable leating from the unit to the tv. STILL HAPPENING!

Like I said, it plays ok, I would just like to clear up the "watery" look. BTW, if I switch it to channel 2, the screen looks pretty good, hardly any interference.

Any ideas? Thanks

[ApolloBoy]

How do you have it connected to the TV? If you're using the switchbox that might be your problem.

[A-T-A-R-I]

I am using one of those RCA to f type connectors.

[A-T-A-R-I]

UPDATE
I also changed the resistor next to the power jack, no change.
Also, I forgot to mention, the "water" look is not constant, It comes and goes every 5 or 6 seconds. It really seems like radio waves coming and going in and out of the screen. I have moved the console to different areas of the house, still the same, but I don't have it on my other units, so it has to be this board.

[A-T-A-R-I]

UPDATE
It does it on color or black & white settings.

[Underball]

RF interference. Make sure your power cable isn't crossing the video/ rf cable. Also make sure to use a good quality coax video cable.

The only way to really eliminate it is to video mod the system to composite or s- video.

[A-T-A-R-I]

OK, been beating my head all afternoon and playing with this board.
I took another one of my 4 switchers apart and when I took the metal shield off the back of that one, it does the same thing that has been going on with the other one, so obviously, it is RF issues.
BUT, the one I have been working on HAS THE FRONT AND BACK COVER STILL ON AND WAS NEVER REMOVED! So how is the rf getting in to it?

[zylon]

It could be getting in through the cable itself. Try one of the cables with a coil on it like the computers used. I had a Jr. that would only work well on channel 2 and was blurry on channel 3. My functioning 600 does this as well, but only on one particular tv. Also, try taking the system to a room that doesn't have a lot of items plugged in on the same circuit. The power supply is another way for interference to sneak in.

[A-T-A-R-I]

Zylon, funny you mention that cable. I have one here with the coil made by Atari which was still brand new. I opened it and tried it, but RF still there.
I tried a different power supply and also moved it to a different room complete other side of living quarters and it's still there.

It's almost like the silver box is off, but it isn't. No gaps, bends, etc.

[zylon]

Might just need to fine tune RF box, or just use channel 2. It's not the end of the world. If you use a metal allen wrench for tuning, be careful not to short anything and to take the wrench completely out of the box between adjustments.

[Herbarius]

Quote

So how is the rf getting in to it?

Well because I guess RF is devils' work It gets through everything... I don't think there really is a practical way to really shield it.

I guess all this is because the RF standard is also capable of and was originally intended to be an "airwave" you get through an antenna...

[A-T-A-R-I]

Tried adjusting RF box, no change.
The sad thing is this was finally the first unit I got that that actually works ok otherwise, except for the RF issue.

[zylon]

I had a 6er long ago that played AM radio through the sound channel. If I moved my finger along the band of resistors above one of the chips, I could tune to different stations.

[tetrode kink]

Herbarius, on Tue Mar 23, 2010 11:41 PM, said:

Quote

So how is the rf getting in to it?

Well because I guess RF is devils' work It gets through everything... I don't think there really is a practical way to really shield it.

Huh?

...wrong in so many ways...

...so little time...

• Big metal box shielding around chips: Works.
  
• Braided wire around signal core in shielded cable: Works.
  
• Stand in front of running microwave oven and your guts don't get cooked: Works.

It may not be perfect, but you said practical.

That last one is quite ingenious; it works and you can still see through it. Also, I'm not afraid of standing in front of a running microwave oven because microwave ovens can't run very fast.

Oh, you were right about one thing: RF is, indeed, the Devil's work.

-tet

[Herbarius]

I'm sorry, I meant "no practical way to really completely shield it"

[A-T-A-R-I]

Well, I have given up. I have tried everything, so I guess I will just use channel 2 when using this system. While still a lot of RF on 2, it is a heck of a lot better than ch 3.

[zylon]

When I lived in the Quakertown area, I had to use channel 2 on my Atari and 4 on my Sega for good video. I think they had a channel broadcasting on vhf 3 if I remember right.