LHE mod problems

[ApolloBoy]

Recently I got an LHE board for my 7800 and I recently finished wiring everything up and testing it all. 2600 games look great on it, but I'm not getting any color for 7800 games. Is this a known issue with the LHE mod or is something else afoot?

[gorfcadet]

Well, mine should be in this week so I'll let you know what I come up with on mine then. Did you look at the solder point to make sure their wasn't just some sloppy connections on it? I've heard that some of the boards are really touchy.

[ApolloBoy]

I got the color working now, but I'm getting some interference, which is odd considering the 2600 side is crystal clear. Any ideas? Also, the external audio is too quiet.

Edited August 7, 2011 by ApolloBoy

[Bradsco]

I got the color working now, but I'm getting some interference, which is odd considering the 2600 side is crystal clear. Any ideas? Also, the external audio is too quiet.

I installed one a of couple weeks ago. No issues whatsoever.

[+Mitch]

Also, the external audio is too quiet.

 

That's because the install instructions for the audio are incorrect. Very common on 7800 A/V mods, all the attention is paid to the video and the audio is pretty much ignored.

 

Mitch

[gorfcadet]

So whats the fix on the audio?

[+Mitch]

You need to add two resistors, one is 6.8K and the other is 18K.

 

On the install page, about two-thirds of the way down, it tells you to solder down the yellow wire bridging two resistors together. You don't want to do that. If it's already installed then unsolder the yellow wire and make sure that the resistors are not connected anymore. Then solder your two new resistors to the two resistors on the board that you removed the yellow wire from. The 6.8K goes to the 6.8K and the 18K to the 18K. Now bridge the free ends of the two new resistors and solder the yellow wire to them.

 

The pic is from the 8bitdomain video mod, it has the same issue.

 

Mitch

 

(Hmm, I really should clean up those solder joints)

[gorfcadet]

Thanks! Sigh... my hands just aren't as steady as they used to be, but I think I can do that. That's what a decade of teaching does to you.

[ApolloBoy]

I managed to fix both problems today! Mitch's fix for the external audio worked fine, and I managed to figure out why I was getting interference with 7800 games. Turns out the TIA line was creating interference, kind of like what's described in this thread. So to fix the problem, I wired up a switch that can disable the TIA line, eliminating the interference completely. Now I've got crystal clear video with both 2600 and 7800 games! Great mod aside from these two issues!

Edited August 8, 2011 by ApolloBoy

[phattyboombatty]

I managed to fix both problems today! Mitch's fix for the external audio worked fine, and I managed to figure out why I was getting interference with 7800 games. Turns out the TIA line was creating interference, kind of like what's described in this thread. So to fix the problem, I wired up a switch that can disable the TIA line, eliminating the interference completely. Now I've got crystal clear video with both 2600 and 7800 games! Great mod aside from these two issues!

 

Wow, I'll check that out. I'm on my second board, sent to me from electronicsentimentalities, and I'm getting 7800 games all in black & white, and 2600 games are completely scrambled or I get a black screen. The b&w 7800 image is crystal clear though. Re-flowed the solder on the tiny chip per LHE's suggestion and everything to no avail. I'm pretty handy with electronics, but I've yet to figure this one out.

[gorfcadet]

I got my modded systems back from electronicsentimentalities today and the 7800 worked great. Audio was good and loud and colors were solid. I haven't tried the 2600 yet because I need a new plug, but the 78 was spot on.

[gorfcadet]

I actually had a problem with my tv giving me a washed out/too white picture when I used s video, but changing the source on my tv to rca and back to svid fixed it so i guess it is something screwy with how my tv handles the signal. Svid is very pretty.

[phattyboombatty]

I managed to fix both problems today! Mitch's fix for the external audio worked fine, and I managed to figure out why I was getting interference with 7800 games. Turns out the TIA line was creating interference, kind of like what's described in this thread. So to fix the problem, I wired up a switch that can disable the TIA line, eliminating the interference completely. Now I've got crystal clear video with both 2600 and 7800 games! Great mod aside from these two issues!

 

Wow, I'll check that out. I'm on my second board, sent to me from electronicsentimentalities, and I'm getting 7800 games all in black & white, and 2600 games are completely scrambled or I get a black screen. The b&w 7800 image is crystal clear though. Re-flowed the solder on the tiny chip per LHE's suggestion and everything to no avail. I'm pretty handy with electronics, but I've yet to figure this one out.

 

Had a very good experience with Joe from electronicsentimentalities. He offered to look at my 7800 board and replaced it with a spare he'd had. I adore LHE's design, and I'm stoked for the support and care offered by electronicsentimentalities. If LHE Is out, check eBay for Joe's sales of the video mod!

Edited August 20, 2011 by phattyboombatty

[Deteacher]

I managed to fix both problems today! Mitch's fix for the external audio worked fine, and I managed to figure out why I was getting interference with 7800 games. Turns out the TIA line was creating interference, kind of like what's described in this thread. So to fix the problem, I wired up a switch that can disable the TIA line, eliminating the interference completely. Now I've got crystal clear video with both 2600 and 7800 games! Great mod aside from these two issues!

 

Could you post directions on how you made this modification? I have the same problem with my 7800 LHE mod. Beautiful color in 2600 mode, b/w in 7800 mode. I'd love to try your switch idea before I send it off to LH for repair.