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Stupid question - have you connected both modules to +5V and SID module to +9/12V? It seems that your core works just fine, so there's probably a problem with your SID module and/or with the connection inbetween. And post some photos of your setup (solderside too) if you can. Maybe we could spot something then. Good luck mate.

Look at this schematic http://www.ucapps.de/midibox_sid/mbsid_v2_communication.pdf Have you soldered a resistor and a diode to your core module?

MBFM sounds *just* like OPL3, cause it is nothing more like an OPL3 chip with additional hardware and software. Wavetable sequencer has nothing common with wavetable synthesis, it's just a sophisticated tracker-like modulation source that makes possible to change every parameter stepwise. So there's no sample playback available at all.

I just bought PIC18F452. I'll program it, replace '4685 with it and check if it helps later. Wish me luck.

http://www.ucapps.de/midibox_sid_manual_fp.html

There's an interconnection test app. Upload it and make a test as described in .txt file. Don't wire your LCD in 4bit mode. As far as I knnw it's reserved for 4620's and 4685's. And good luck since my mbfm doesn't make a sound either.

I suggest doing some continuity tests on YAC's and YMF, because it looks like some legs are covered with solder but I am not sure if they're all soldered to the pads. Maybe pour some flux and re-heat them, just to be sure. And read this post that covers running MBFM on PIC18F4620, cause you may have to upload MIOS designed for another PIC to get the whole thing working.

As a temporary solution I soldered 4 short wires to the 8-pin socket with bent legs, and on the other side I mounted a connector. It works like a charm and I can switch it really fast between cores. I think it's the easiest and quickest solution, that doesn't involve soldering your chip directly to the pins on the core module.

It sounds more like a heavy digital noise (btw, cool name for a band:), than a testtone, but I can't compare it, cause my mbfm can't speak right now. Better slow down, check all your connections between core and opl3 once more and try again.

My core module runs from stabilised PSU. Bridge, 7805 and caps aren't mounted on my pcb, and it works. So it's ok. But in the meantime I installed second YAC512 and swapped YMF262 and nothing changed. I think the problem is in communication between core and OPL. I think my '4685 wants to be replaced with '452...

My soundcard arrived today, pretty, isn't it?:) Next step: to desolder everything useful, then back to debugging my OPL3 module.

Yesterday I bought another soundcard. I'm waiting for the delivery now and than we'll see if that works.

Using 2 PSUs is rather inconvenient. You can do it temporarily, but you should avoid it in your final design. But don't worry you have number of solutions: you can buy another C64 PSU on eBay or something like that really dirt cheap and re-use it without modifications or you can use this 9V PSU you have for +9V and +5V, but then you have to design another PSU and use some heatsinks for 7805 regulator. There are appropriate schematics somewhere in the forum, in the midibox FM section I think.

Measuring voltages on unloaded PSU is one thing, on loaded - another. Try to connect another PSU (wallwart or whatever you have with similar voltage) to your circuit and measure the voltages after the bridge and avter voltage regulator. Good luck!

Nope, I only connected the LCD in 4bit mode but it was when running '4585 firmware. I saw 'ready' message, interconnection and testtone messages, and some garbage after uploading mbFM software. After switching to '452 firmware I don't use the LCD. I know I should wire it in 8bit mode but I don't want to desolder the wires, cause it's a part of my *working* mbSID. When I find an appropriate 2x40 LCD, I'll connect it in 8bit mode.