I recently got a Model 1 High Definition Graphics Genesis to replace my Model 1 VA7. To get stereo sound I made sure that the audio was coming from the headphone jack and not the AV connector. I plugged it in and turned it on today and was surprised to hear that the audio sounded terrible. On further inspection the right channel audio was perfect, dynamic, and clear. The left sounded really muffled and distorted. I double checked to make sure it wasn't my speakers or the cable itself (3.5mm - dual RCA). Here is a quick video I recorded which shows the right channel, both channels, then the left channel. https://www.youtube.com/watch?v=YU8WLBelza4 If anyone has any idea of what causes this issue or how to fix this issue please let me know. The mother board says both VA5 and VA6 on it so not really sure which one it is. Can take pictures of the MB if it helps.
Unfortunately I only seem to be able to find Model 2 service manuals online. Could it be a dirt issue or is the chip itself broken? The board was pretty dirty but I cleaned it up a lot but no change in the sound. Did some extra cleaning around the chips you mentioned as well. Interestingly enough when I move the headphone slider it seems to effect more than the volume level itself on the left side, it makes it a lot more muffled when in a certain position (30% and lower).
I had exactly same problem with my Japanese MD just after replacing capacitors. I checked everything I could possibly change, and I didn't found source of problem. But it's interesting that after several months problem disappeared by itself. It still puzzles me.
Start with the basic stuff, clean volume slider with contact cleaner and check the headphone jack for bad contact/broken solder joints.
I will try that, I think it is more than the headphone jack because the mono audio from the AV port also sounds really off (although it doesn't get worse when I move the headphone volume slider, obviously). I assume since the AV audio cable is white the the genesis just gives it the left channel, so I think it might have to be something happening to the audio before the outputs, but I could be wrong. Would using an unofficial power supply cause this issue? I used the same power supply on my Model 1 VA7 and had no issues.
What are the specs of your Ac adapter? Official one is 10vdc 1.2amp. If you use an underamped PSU it could cause problems but I doubt it would be a muffled audio channel. More like random resets, glitch and that kind of stuff and PSU overheat. If I had to place a bet on something I would say Bad caps. But Its always good to check all the basics very well.
I checked my adapter and it appears that it is at 9vdc 850, so it is underpowered, haven't had any resets, glitches, or power related issues though, think that it's possible that this is the problem?
I guess its not impossible. The VA7 does not take as much power as the older HDG ones. It worth a try to get a good adapter. Check the polarity is right before trying a new one though.
If Amiga's are anything to go by this will be either a failing capacitor on the audio or power circuit or failing capacitors in the PSU. Given its only on the one channel, I'd look at the audio circuit for the left channel first. Typical signs are swollen tops on the capacitors, bulging and a very feint scent of cat pee (electrolyte fluids scent) if it has begun to leak. If this has happened it can begin to erode the solder pads so you may want to replace it as soon as possible. The electrolyte caps used in systems of this age have an average expected life of around 20 - 25 years or so depending on usage, storage conditions etc. Many systems using these are starting to fail now sadly. We see a lot of it over on Amibay with the Amigas and similarly aged systems. EDIT: Just spotted the post about the PSU. I wouldn't have even expected a 9V adaptor to power the thing. Definitely try an official one first.
Genesis has 7805 voltage regulator inside, which means that voltage > 5V will be converted to 5V. Any excessive current will be dissipated as heat, that's why you see there big heatsink. That said, better to use less voltage, but of course it should be >=5V. PSone and PStwo external PSU's are very good to power up old consoles.
While this is technically true, Ive been told that the 7805 needs some voltage overhead to operate properly. Apparently in this case it would need about at least 7-7.5v.
Exactly, psone psu is stabilized 7.5v, which is perfect. However I am still dreaming to have only one power source to power mega drive/mega cd/32x with one psu, pstwo should be powerful enough (at least mega drive and mega cd have 7805 inside, but I am unsure about 32x).
http://gendev.spritesmind.net/forum/viewtopic.php?p=18847#18847 for model one service manual. as for muffed sound i recapped one once and still the same i am yet to get extra ic to replace i would say to use sockets and use wire cutters to cut out the old chips. to save PCB damage.
By all mean dont do that!!! Just get a heat gun and cleanly remove the old chip without damaging any pins! They dont make make most of these chips anymore you know? No reason to destroy it when it might not even be defective.
@nesboy43 Soz for bumping a near 3 yo thread, but I have this exact problem. Did you end up finding the source? I have done the following bit am still yet to resolve the issue: - Full recapping - Swapped the headphone jack - Swapped the volume slider - Replaced the CXA1034 (as suggested by @bart_simpson)
