ChipMusic.org - Noisy buzz on output after installing backlight kit

Re: Noisy buzz on output after installing backlight kit

2017-02-19T06:38:18Z

My DMG-01 had the same loud hum on the pulse channels like the OP talks about (disappears after a K[ill note] command is played). Removed the bivert chip (didn't try to ground the unused pins as suggested though), and it's all good. So, thank you thread.

Re: Noisy buzz on output after installing backlight kit

2012-02-28T02:07:33Z

SO I made sure my batteries were full and then messed around a bit, when the contrast is at an exact half it does look inverted but is very very hard to see, when any higher (as in turning the contrast dial away from yourself) it becomes impossible to see, the only thing visible is the word "song" in LSDJ and when cranked the whole screen becomes whiteish.

When the contrast is darker than half (turning the dial towards yourself) it then becomes normally polarized and is quite view-able except for the word "song" up in the top left corner in LSDJ, and when cranked all the way is black.

I tried tightening and loosening screws to no avail, and looks the same way when the front PCB is dismounted, I have no clue what exactly is going on.

Re: Noisy buzz on output after installing backlight kit

2012-02-28T01:27:39Z

Inverted is basically what is says.. inverted..
the black pixels are now white, and the white pixels are black. This is because the polarised sheet that is placed behind the screen is turned 90 degrees.

the reason people use this, is because it also turns the spacings between the pixels black, thus creating a bigger contrast in the screen. The problem with the contrast is indeed a bit anoying sometimes, and varies from colour to colour.. Make sure your batteries are full...
So you should get an inverted picture, if you get a normal picture, or half a picture, change the batteries, and adjust the contrast...

If you still have trouble getting your picture right, you might want to try and untighten the screws in your gameboy just a little bit (pcb or case) as the backlight takes up some room, the screen can sometimes be squashed causing the pixels to fade (Like what happend when you press your finger on your calculator screen)

Re: Noisy buzz on output after installing backlight kit

2012-02-28T00:51:07Z

Hmm, as a side note to this conversation I just got my backlight and LSDJ today, and it was supposed to be inverted but I m not sure that it is... when turned on the Nintendo logo is black... and I can never get the contrast quite right, when most of the screen looks normal the upper corner is barely visible but when I adjust it to show the corner the colors do invert but I can't see the rest of the screen

I am using Kitsch's LED x3 Green (supposedly inverted)

Re: Noisy buzz on output after installing backlight kit

2012-02-27T23:08:50Z

Ah yes, It could be from the other ports... Doubt it's from the long wires, because I mounted it right on top of the pcb. wires aren't even a centimeter...

Might try and ground the ports on my DMG, to hear if it makes any difference...

Re: Noisy buzz on output after installing backlight kit

2012-02-27T21:53:20Z

Maybe the buzzing came from the four unused inverters in the hex inverter not being grounded. It's always a good idea to ground unused inputs to stop them floating and then oscillating between logic high and low. Or maybe it's EMI from using long wires to/from the hex inverter. Just a theory :-)

I didn't notice any buzz when I installed a dual inverter in my DMG: http://chipmusic.org/forums/topic/6031/ … -mount-ic/ Perhaps it's because there are no unused inputs or long wires.

But you're right, LSDJ users don't really need it... it's only good for using your DMG for something else (like game carts).

Re: Noisy buzz on output after installing backlight kit

2012-02-27T15:01:50Z

But in all seriousness. I don't have that much technical insight that i know what really caused the buzzing sound. I biverted my gameboys as well, but I never noticed it before.. (Then again, I'm not as anal about my sound as Monodeer )
I couldn't tell you if it happens with all biversions, or just the version of chip that I used. It looks like the chip somehow interferes with the sound of the gameboy, but I've got no clue as to how. It's one of those things that shouldn't happen, but still does.

If you're going to use your gameboy just for LSDJ, you can easily just get an inverted backlight and then use an inverted colourscheme in LSDJ, works the same as biversion, without the hassle of soldering hex inverters etc.

Glad i could be of little help

Re: Noisy buzz on output after installing backlight kit

2012-02-27T14:51:50Z

MONODEER wrote:

Yes you are! At least, Timbob was able to do it for me He will probably add some more technical info after we put some new life into this post. So, if you are not in a hurry, more info from him will soon be here. Otherwise: Good luck!

Re: Noisy buzz on output after installing backlight kit

2012-02-27T14:04:25Z

Not in a hurry at all, I may have another day or so for shipping so I will keep checking this thread until then.

Re: Noisy buzz on output after installing backlight kit

2012-02-27T13:55:30Z

Yes you are! At least, Timbob was able to do it for me He will probably add some more technical info after we put some new life into this post. So, if you are not in a hurry, more info from him will soon be here. Otherwise: Good luck!

Re: Noisy buzz on output after installing backlight kit

2012-02-27T13:51:51Z

I went ahead and bought an inverted backlight and the hex inverter, so I might as well try it out and see, as far as you know you are able to repair the traces on the PCB right?

Edit: I was scared for a second that I actually necro'ed this post but I realized you had posted before hand

Re: Noisy buzz on output after installing backlight kit

2012-02-27T13:48:49Z

I don't really know the technical inside specificics nor do I have the technical knowledge of how to make the biversion work.

When I posted about this problem, nobody really seems to know what was the deal, so I hope you can make it work if you really want to do it. I have to admit that the biversion made the screen look sharpen than without it, but I don't think it is really worth it the risk of having shitty buzz at the end of it all.
If you don't want to risk the hassle, I would go for a normal backlight kit.

Re: Noisy buzz on output after installing backlight kit

2012-02-27T13:38:09Z

Does anyone know if this is the case for all biversions? I planned on doing one but I don't want to if it causes an audible buzz...

Re: Noisy buzz on output after installing backlight kit

2012-02-27T10:49:53Z

FIXED!

After some testing, we came across the fact that it was definately the biversion that caused the buzzy sound!
So, we (read: Timbob) removed the chip, then restored the circuit and fixed me up with two fresh modded DMG's.

Two days later I took them to Blip Australia and put them to the master test!

Re: Noisy buzz on output after installing backlight kit

2011-12-18T11:36:53Z

Oh dear, I broke Monodeer's gameboys...

to the fix!