stryd_one Posted April 26, 2008 Report Share Posted April 26, 2008 Why are you connecting the LCD to the 7812? Quote Link to comment Share on other sites More sharing options...
syamajala Posted April 26, 2008 Author Report Share Posted April 26, 2008 its the backlight for the lcd. It needs +12v. Quote Link to comment Share on other sites More sharing options...
stryd_one Posted April 27, 2008 Report Share Posted April 27, 2008 Err whad ya grab that freaky LCD for? :-\I assume you connected it to the 12V ground, not -12V?That 12V supply is really meant to stay nice and clean for the audio output anyway... But aside from that, I wouldn't have thought that the LCD should draw that much juice. if you put your meter in series with it, how much current is the backlight drawing? Seeing as it's just that backlight, it shouldn't be enough to overheat the 7812, so maybe there's a short somewhere, or the backlight is dead... I dunno. How much current does it draw if you disconnect everything from the LCD and just connect the backlight? Same as the above?Oh - how are you splitting up the 12V to the LCD and OPL board? in series or parallel (a spot of ascii art might help here) Quote Link to comment Share on other sites More sharing options...
syamajala Posted July 22, 2009 Author Report Share Posted July 22, 2009 I decided to start working on this project again. They are connected in parallel. The lcd backlight draws more than 1 amp of current when its on. I think I need a current limiting resistor in series with the backlight right? When I disconnect the lcd backlight the 7812 doesn't get hot.Now time to figure out whats wrong with the sound. I've started working in a physics lab at school that has this really neat soldering iron that looks kinda like a pair of needle nose pliers for soldering ics, that would probably help with getting some opl chipsets to test. That was the most frustrating part of this project and why i stopped working on it. Quote Link to comment Share on other sites More sharing options...
Janis1279 Posted July 22, 2009 Report Share Posted July 22, 2009 I decided to start working on this project again. They are connected in parallel. The lcd backlight draws more than 1 amp of current when its on. I think I need a current limiting resistor in series with the backlight right? When I disconnect the lcd backlight the 7812 doesn't get hot.Why 12volts to the LCD module ?If you see scheme of MBHP Core , you see only +5V and gnd connections, right? Your comments about more than 1 amp of the LCD backlight current sounds : all is not so good. You need against checked every connection to the LCD module .Regards, Janis Quote Link to comment Share on other sites More sharing options...
syamajala Posted July 23, 2009 Author Report Share Posted July 23, 2009 if i remember correctly thats what the datasheet for the lcd said the backlight needed. I don't have it anymore and am trying to find it online, but there isn't a lot written on the lcd. i hope i can use this because i have 2 more just like it. Quote Link to comment Share on other sites More sharing options...
syamajala Posted July 23, 2009 Author Report Share Posted July 23, 2009 after replacing the ymf262 i got sound with the test tone generator for a couple of minutes and then it stopped working. I'm only using 1 yac512, i need to get another one. I hope i didn't mess up the opl3. I hate having to desolder them and resolder them. Quote Link to comment Share on other sites More sharing options...
Janis1279 Posted July 23, 2009 Report Share Posted July 23, 2009 if i remember correctly thats what the datasheet for the lcd said the backlight needed. I don't have it anymore and am trying to find it online, but there isn't a lot written on the lcd. i hope i can use this because i have 2 more just like it. If you returned to the scheme MBHP_CORE_V3 to the connector J15, will see pins in the two columns. Right sizes first 2 upside pins are marked : B+ , B-. These pins supply voltage "+" and "-" polarity ( or need suplly voltage ) to the yours LCD backlight pins. I have simpler this part of the scheme with only one 10E resistor , but its not so important.Regards, Janis Quote Link to comment Share on other sites More sharing options...
lead bromide Posted July 24, 2009 Report Share Posted July 24, 2009 Perhaps post pictures of your setup? Quote Link to comment Share on other sites More sharing options...
syamajala Posted July 30, 2009 Author Report Share Posted July 30, 2009 it looks like i messed up the opl3 and yac512. I tried replacing the op amps but still didn't hear anything. i also tried powering the lcd backlight from the 7805 and even that got hot. I need to get some more sound cards. I have 1 more pair of chips, but if i mess those up i'm out. anyway it should be fairly easy to get at them now that i have access to a nice iron. Quote Link to comment Share on other sites More sharing options...
fussylizard Posted July 31, 2009 Report Share Posted July 31, 2009 If you're trying to de-solder the chips (more) safely you might consider Chip Quik (http://www.curiousinventor.com/store/product/102). Pretty amazing stuff and makes de-soldering stuff easy. They have a video of it. Quote Link to comment Share on other sites More sharing options...
syamajala Posted August 13, 2009 Author Report Share Posted August 13, 2009 Now that i am using the proper method desoldering smd chips is easy and i can generally do it in a matter of minutes. I used a method similar to the chip quick method but with regular solder and a desoldering iron with a bulb. i haven't tested out the chips i took off yet, but they didn't get as hot as they normally do when i desolder them, so hopefully they will work. i also decided to get a new lcd, because i wanna make my fm look cool. I'm gonna try and go with a blue and white scheme, so i got an lcd with a blue backlight and white text, and some blue and what should be white leds. Quote Link to comment Share on other sites More sharing options...
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