183 replies to this topic

[Underball]

Look at the picture you posted.

You removed R4 & R5. R4 is part of the video circuit.

Edited by Underball, Sat Sep 25, 2010 1:22 PM.

[ramdass]

Underball, on Sat Sep 25, 2010 1:19 PM, said:

Look at the picture you posted.

You removed R4 & R5. R4 is part of the video circuit.

I'm mortified. Must be creeping senility. Changed it to the correct resistors and the audio works fine.

[PacManPlus]

Just as a side note, this mod also works for the 'Stunt Cycle' stand alone SC-450. Specifically, I did this one: http://www.atariage....ost__p__1796143

No resistors to remove, and the audio already has it's own connector.

[Deteacher]

I can pretty much follow all those steps, except for the 7800 Amplifier schematic (I have never been able to read schematics.)

Would it be possible to post a picture of the assembled amplifier, labeling the parts? With a pic of the real thing, I could probably build it with little to no problem. Sorry. I'm just getting into this aspect of tinkering (I'm getting pretty good at soldering now) and I'd love to attempt this mod on my own before taking it to someone to do it for me.

I know...I'm a n00b!

[twoquickcapri]

Thanks to everyone who took time to work on this mod. I Had an 7800 that need a new power switch so I figure while I was in there in would A/V mod too. I used Underball's instructions.

I removed the RF unit and removed its guts. then I removed the channel switch to make room for the sound phono. I reused the case to mount the video phono and then used the bottom of the case to make a mount to house the sound phone.



Then remounted it to the board and did the A/V mod.


Was able to the mod without cutting the case

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[ApolloBoy]

Very clever reuse of the RF modulator!

[iesposta]

I just finished this easier 7800 A/V mod on my lousy Serial #X201 7800.
I did Post #97 PacManPlus way, only with parts I had, the $0 mod
I didn't have a 75 ohm resistor (did anyone??), so I used a 82 ohm resistor instead.
I didn't find any RCA connectors, so I used a cord that ended in female RCA jacks.
Thanks for the tip that the Atari XM301 Modem has three of those value transistors!
I also had used the modem's box for an SIO2SD.
I'm quite pleased with the video and sound, however LittleJoe's 'Longhorn' 7800 A/V mod with S-Video is nicer in my opinion.

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[AtariBrian]

will the xm work with modded systems?

[mimo]

AtariBrian, on Fri May 4, 2012 10:10 PM, said:

will the xm work with modded systems?

yes