Jump to content

the beginnings of a fm


syamajala

Recommended Posts

  • Replies 61
  • Created
  • Last Reply

Top Posters In This Topic

  • 4 weeks later...

ok, so worked on my fm stalled for a while, because my grandfather passed away. However, I had a bit of time to work on it this weekend and i finished the power supply. So, if i connect the opl3 module to the core i should be able to test it out.

Sorry to hear about your loss. Good to see you making lots of progress man,

your work will be really helpful when newbs like me try to start one.

Link to comment
Share on other sites

  • 3 weeks later...

Hey guys! Its been a while since I have posted an update, anyway I just pulled out my mb stuff, and I hooked up the power supply and checked all the voltages. Everything seems to be good!!!! The opl3 board is getting the +5v, -12v, and +12v. I checked the voltages at the sockets for tl074s everything is good. Also checked the voltages for the core at pins listed on ucapps, and everything is fine there. So, I guess I need to put the pic in, the tl074s, and the optocoupler. Then figure out where to go from there.

Link to comment
Share on other sites

I don't think all the channels are working. It appears as though only 2 of them are. But that is just with the test tone app. I still can't figure out how to use jsynthlib. I downloaded the preset patches from ucapps and sent one to the fm, but when I try to play it nothing seems to happen. Is there a guide on how to use jsynthlib?

Link to comment
Share on other sites

I'm having a weird problem. I hooked up a lcd to my core and its working, but the 7812 in my power supply is getting really hot. I have a heatsink on it. I also noticed that the output of the opl3 module is really loud when I hook up the lcd. After I hooked it up I loaded the test app again and couldn't hear anything, but on the lcd it said test tone generator. I also loaded the fm app and could see it changing patches when I was playing with jsynthlib, but I still couldn't hear anything. Is the lcd drawing too much current and causing the 7812 to heat up and cause the other problems? Also does anyone know if that recording is what the test tone app is supposed to sound like?

Link to comment
Share on other sites

Something is definately wrong here. The test tone should be 1khz and played on all four channels. My MBFM is in my workshop and I'm going away for vacation for a week so I can't record the test tune, but tyr google for 1khz test tune and you will know what it'll sound like.

Have you checked, double checked and tripple checked every connection between the core->opl3 module->psu against the wiring diagrams? Have you checked for any soldering problems on the opl3 board?

/offe

Link to comment
Share on other sites

the 7812 is only getting hot when the lcd is connected. If I disconnect it, its fine. I checked all the voltages with my multimeter after I connected the core to the right +5v. I'm using the bipolar power supply found here http://www.midibox.org/dokuwiki/northernlightx I had originally connected my core to jp6, but then I realized i'm supposed to connect it to jp5. I'll worry about the lcd problem later I guess I should first try another opl3. I think one of the yac512s might also be burnt out, because only 2 channels are working.

Link to comment
Share on other sites

I'll worry about the lcd problem later I guess I should first try another opl3. I think one of the yac512s might also be burnt out, because only 2 channels are working.

Although I think you may be right, that might not be the best way to find out. At this point, you should really disconnect all the peripheral boards (like the OPL3 module) and just work on the core.

The 7812 should have nothing to do with the core at all, it's only for the audio circuitry on the OPL3 board, so I don't understand why the LCD would effect it. I suspect you have a short circuit somewhere.

Trying another set of FM chips might help, it might also blow them up as well. Fix the core first. (see my signature - one at a time)

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...