SEGA GENESIS hedphone jack not friendly with HDTV.

[Digimaks]

Hello all, mighty retro game lovers and tech gurus!
I need some tech insight and advice please:
Few years ago I bought Sega Genesis platform, model 1. And I used to hook it up to HDTV though RF box. However the picture quality was grainy. In addition the TV seem to have automatic antenna adjuster, which caused the video to disappear when the game shows more then 50% black pixels - seems like auto adjust thought the signal was lost or something. (When you move back to non0black pixel areas in the game- the picture restores.)

Anyways, that being said- I created my own AV video two pin plug for 8 pin DIN (pin 1 and 5).
- The video quality is awesome now!

HERE'S THE PROBLEM - When I use the AV Cable: DC3.5mm Headphone to RCA Stereo
I connect it to front Sega's headphone jack to L - R on the HDTV, it results in Genny not starting up at all, no video or sound (the red light is bit dimmer then normal).
- Maybe something wrong with cable or the headphone jack?
TESTED - plugged it into my guitar amp AUX IN - sound works, (except for minor humm and maximum loudness, regardless of amp controls.)
TESTED - Plugged sega's headphone jack to laptop's line in - works fine, (maximum loudness, regardless of the laptop volume.)
TESTED - plugged in headphones - works perfectly fine.
RESULT - Genny's headphone jack is working fine.
But it just does not make friends with HDTV AUX input. If plugged in during the game, it freezes up and screws up the video. If plugged in and turned on- Sega doesn't start up.
Why is it? How to get that headphone-out to work with HDTV? Am I missing some steps, or it is simply not compatible?

P.S. - Yes, I know there are sound pins on 8 pinout, but it's mono. The reason I am trying to get stereo to work with HDTV AUX, is to get the best out of Sega capabilities.

Thanks in advance!

[Hobie-wan]

The hum and maximum loudness makes it sound like there's a problem with the volume slider. Using the headphone jack with it set to some sort of medium volume should be just fine with a TV, amp, or anything else that accepts line level input.

[Digimaks]

No, it isn't. That's the first thing I tried. Whenever I plug it into HDTV L-R audio, it simply crashes Sega, or never let it start. And the red light bulb on Sega is VERY dim, until I unplug it from TV.
Is there such thing as bitrate or latency that could be causing it not to work properly?

[Hobie-wan]

The headphone jack is just pure dumb analog. You're using a Y cable that only has 3 connections on the Genesis end, not one with 4 and has 3 RCA plugs like a mini DVD player might have to hook video plus stereo sound are you.

Wait, why are you using pins 1 and 5 on the Din? You should be using 1 and 2, video and ground not the 5 volts. Fix your cable before you fry something. Try the genesis without your cable, just the sound hooked to the TV.

[Digimaks]

Oddly enough, Sega gets stuck even when I connect it to TV though amp or audio center......
However it works great with audio center itself! That is just odd. There is something Sega did not like about HDTV audio in particular.

[Hobie-wan]

That sounds like the problem is with the TV itself then. The audio is just a low voltage analog signal. It can't be incompatible with the TV other than an overly strong signal which should only happen with a malfunctioning Genesis (but you said it works fine with headphones and the amp by itself) or a malfunctioning input on the TV. I'd be wary of plugging other things in since you say the Genesis acts strangely when connected, but if you decide to try it, do other things hooked to the audio input of the TV act funny?

[Digimaks]

Not at all! I got DVD, VCR, Sega connected to the AV selector port.
All work fine, except for Sega AV sound when connected. (yep, tried swapping connections, no difference)
What freaked me out even more - I connected Sega to Laptop line-in, and ran cable from laptop headphone jack to HDTV PC audio input. (sort of attempt to re-initiate sound signal though in-between device) Same thing happened! LOL!

Anyways, I decided to keep the sega Av stereo sound connected to audio center instead of TV. Works flawlessly this way with even better sound from audio center, which splits into left and right speakers, as well as sub-woofer. Sort of overkill for 16 bit platform, but what tha heck !

For some reason Sega headphone jack worked with everything but not the HDTV for odd reason. Looks like there is something HDTV or SEGA did not like in terms of sound signal.
I always thought all AV sound outputs are standard.

[Digimaks]

I swapped +5 to ground. Maybe it was causing conflict with audio channels from headphone jack, when connected to SAME DEVICE ?

[Digimaks]

YEP! That is it!
Thanks for pointing it out! Well good thing I avoided hurting the platform by having it hooked up to separate sound device.

THANKY!

[Hobie-wan]

Glad it's cooperating now and nothing let out the magic smoke.