mb-6582 very low output and hanging notes.. sounds familiar?

[lief138]

So I seem to be having the same problem as synthesizerbauen had (http://www.midibox.org/forum/index.php/topic,11710.0.html)

I thought I wasn't getting any output but after jacking the mixer all the way up I was able to hear the sounds. Also, all notes hang.

It looks like his solution was to replace the 7809. I will pick a couple up after work tomorrow.

Everything else seems to be fine. I went back and double checked all the power tests in the baseboard guide.

Im posting this with the hopes that someone else might have some ideas about what might be wrong or what else I might check, as I only used the c64 psu and I dont seem to be having any other problems. I thown there must be at least a couple people who would have some ideas.

Also, I will say that last night after I uploaded the hex files I plugged in headphones into the sid 1 output. At that point I didnt hear anything at all.

On the chat today I was told that I needed to plug the SIDs output into a mixer. I dont know if this could have caused a problem.

OK help a brother out :)

Lief

[Wilba]

Try the testtone app: http://www.ucapps.de/mios/mbsid_testtone_v3b.zip

Upload the app.

First test the output amplifiers, remove all SIDs, bridge SID socket pin 8 with 27 with a bit of wire or a resistor (anything less than 1K should work I think).

This will cause a 1kHz test tone to go through the audio buffer section. Make sure your mixer etc. can playback this tone.

Then power off, insert the SID and power on again, see if you can hear the SID at the same volume.

A sagging 9V supply might be the cause - have you tested just one SID on the board, and tested the voltage on the 9V supply while it's running?

If it's drawing more current than the PSU can supply, the voltage won't be up around 9V anymore... and perhaps that's the problem (SID's internal analog section can't amplify).

[lief138]

OK

I loaded the testtone on to each core. I was able to hear the tone from the 8 and 27 pins load and clear on each sid socket. I put back in the two sids and measured the 9V on J1_SID1 and J2_SID2 and got 9.3V. I still do not get the tones from either sid?

I reloaded the setup_mb6582.hex and I can still hear the sounds. I have also confirmed that I am getting the sounds from both left and right so it seems both sids still work?

I have failed in my mission to get another 7809 today. My place had none....

I also checked with another c64 power supply and still have the same issue

Any other ideas????

[Wilba]

What PSU Option are you using?

Did you connect a jumper between the "9V" and middle pins of J1_SID1 and J2_SID1? i.e. to supply pin 28 of the SID with 9V?

Just a guess. You say you measured 9V at J1_SID1 and J2_SID2 (probably meant J2_SID1), so I thought maybe a missing jumper would mean there's not actually 9V going into the SID at all.

If you don't get the testtone app to make sound out of the SID, then the next step is testing Core->SID connections. Or alternately, upload testone app and put the PIC into a different slot, perhaps another set of Core->SID connections will be good and you can validate the SIDs work etc. But the fact that you're getting low volume tone suggests the digital side of the SID is working fine (Core->SID connections are all good) and it's just the analog side of the SID that is not. Hence some missing 9V supply.

[lief138]

OK unfortunatly I am work now again, but....

I used power supply option A

I didnt put any jumpers on the board at all with the exceptions of the feedback jumpers becasue I do not have the pots yet.

When I measured the power I touched the J1_SID1 9V pin and the ground pin ofJ? in the power supply area.

and yeah I meant J2_SID1

So Now I am feeling extremely stupid because I did not put those jumpers on. I can understand now that obviously the jumper would pick which power actually went into the SID, so if you had the PS option for both 9 and 12 you would just change out the caps and swap that jumper to change out for the 6581...

Well now Im thinking about going home sick ;)

I will let you know asap if this was the problem.

Also, I am going to go back and figure out what part of the instructions I ignored.

Thanks a million

Lief

[lief138]

Good Sweet Mother of God!

Sids work alot better when they get power. Core 1 and 2 loud and clear. I couldnt wait to test the last two before I told people what a fool I am. Either way dont forget the jumpers!

OK Thanks for the troubleshooting Wilba.

[Wilba]

It's good to hear it was just a minor oversight.

I've updated the wiki with this extra info - I think it's important people know about and can run the testtone app first, with that pin 8/pin 27 bridge.