root42 wrote on 2020-06-16, 11:40:

Indeed. I *THINK* I put everything in there (except for the STM32), so you probably you need actually LESS.

@benedikt: any chance that in the future we might simply have three jumpers, to choose STM32/6581/8580?

Furthermore: Look at what I just got on loan - let's hope it still works!

A jumper based solution would not be that easy. Firstly, the STM32 version omits the entire clock divider circuitry, and secondly, the different SID variants need different filter capacitors, as well, not just a different supply voltage.

If you have a clean 12V supply, now, I expect the 6581 to work just fine, unless the chip itself is broken.

I will try it out. 😀 By the way: I will assemble my 2nd board. The first one is already shipped out to the lucky winner. On the 2nd board I will follow your notes for a 12V supply for the 6581. Then we can also make a comparison between the SwinSID and the 6581.

Ok, I am almost done soldering. However I do not understand your notes fully. Do I need to populate C20 and C21 for the 6581? The schematics don't mention those... Also the voltage regulator is not needed, right? Because I can take the 12V from the ISA bus

EDIT: Found the second note that speaks about C20. C21 isn't mentioned, but since it seems to be in the tuning circuit for the voltage regulator, I guess I can leave out all the small filter caps.

What is then the difference between the 6581 and the 8580...? You said it's not only the voltage.

root42 wrote on 2020-06-16, 20:24:

Ok, I am almost done soldering. However I do not understand your notes fully. Do I need to populate C20 and C21 for the 6581? The schematics don't mention those... Also the voltage regulator is not needed, right? Because I can take the 12V from the ISA bus

EDIT: Found the second note that speaks about C20. C21 isn't mentioned, but since it seems to be in the tuning circuit for the voltage regulator, I guess I can leave out all the small filter caps.

What is then the difference between the 6581 and the 8580...? You said it's not only the voltage.

C21 is merely a bypass capacitor on the 12V line. It should make the SID's 12V input a tad bit cleaner, but it is completely optional. And yes, for the 6581 you omit the voltage regulator and bypass it with a solder bridge.
The 8580 technically needs different filter capacitors, but I am not quite sure about their value. Probably 6.8nF, because the 6581 version also uses the values from the data sheet, not the ones the C64 uses.

Oh dear... it kind of works with the SID 6581... But I only get one voice. 😁 Could it be that the SID is defective? Or some problem with addressing?

EDIT: The SwinSID that I have outputs NOTHING. So maybe something wrong with the PCB? Bad solder joints? I have to double check....

root42 wrote on 2020-06-16, 21:29:

Oh dear... it kind of works with the SID 6581... But I only get one voice. 😁 Could it be that the SID is defective? Or some problem with addressing?

EDIT: The SwinSID that I have outputs NOTHING. So maybe something wrong with the PCB? Bad solder joints? I have to double check....

The weakest link in the audio section of the PCB is probably the 5V line to the SID with its two tiny VIAs. Does the chip get its 5V?

Vcc ist 4.7V und Vdd 12.6V, ohne dass ich den Sockel bestücke. Gemessen an Pin 25 und 28.

root42 wrote on 2020-06-16, 22:23:

Vcc ist 4.7V und Vdd 12.6V, ohne dass ich den Sockel bestücke. Gemessen an Pin 25 und 28.

4.7V seem a bit low for a 5V line without load. Could you measure the resistance between the power pin (i.e. pin 20) of the bus transceiver and SID VCC (pin 25)?

Benedikt wrote on 2020-06-17, 09:01:

4.7V seem a bit low for a 5V line without load. Could you measure the resistance between the power pin (i.e. pin 20) of the bus transceiver and SID VCC (pin 25)?

Yes, it seemed a bit low to me as well. I will measure that when I am back home. I wonder if that could also be the reason why the SwinSID doesn't work. I mean, it could be faulty, but I have no way of telling right now. I might get a C64 on loan in the next days, so I could test all the SID variants in there, once I made sure the voltages are right, and it's one that doesn't use an 8580...

Just measured Pin 20 on LS245 to Pin25 on SID reads at 0 Ohms. Which is fine, I guess?

EDIT: I measure 4.76V on all 5V pins in my 386, e.g. on spare Molex connectors etc. And steady 12.6V on the 12V line. I am using a modern modular ATX PSU. I would have assumed that it is pretty good quality, but maybe it dislikes the 386 and supplies too little? However all the other cards seem to work fine...?

root42 wrote on 2020-06-17, 15:07:

Just measured Pin 20 on LS245 to Pin25 on SID reads at 0 Ohms. Which is fine, I guess?

EDIT: I measure 4.76V on all 5V pins in my 386, e.g. on spare Molex connectors etc. And steady 12.6V on the 12V line. I am using a modern modular ATX PSU. I would have assumed that it is pretty good quality, but maybe it dislikes the 386 and supplies too little? However all the other cards seem to work fine...?

Oh well. That rules out that.
Since you still get one voice out of the SID I guess the clock circuitry works and the address circuitry at least partially.
Maybe one of the address signals to the SID is messed up.

Be aware, SID is really really easy to break, just by touching it after walking over carpet for example.
Do you have a C64 to verify the Chip ?

I will receive another SwinSID and also a C64 on loan from a friend in the next days. Then I will be able to test all of them.

Do you still use the flaky Socket for SwinSID ? if its slightly bend that also could be the error.
I remember running circles because my SSI-2001 did not sound right, until i switched the Socket.

Often very simple things are making problems 😀

Benedikt wrote on 2020-06-17, 15:44:

Since you still get one voice out of the SID I guess the clock circuitry works and the address circuitry at least partially.
Maybe one of the address signals to the SID is messed up.

Yes, I noticed that of the 5 address lines, only the first 3 are needed for voice 1 to be active. So maybe line 4 and/or 5 are damaged. I guess the 74LS138 are responsible for that? I will have a closer look at those. I really need a scope....

EDIT: I do have continuity from ISA bus address lines 0-4 to SID address lines 0-4. Which is I guess... ok?

The LS138 is Adress Decoder
If SID is accessed its ok.

I suspect the SID is damaged and the SwinSID is borked as well. The fiest SwinSid worked fine. I sent that one out after the giveaway. What about your SwinSID, @matze79?

root42 wrote on 2020-06-17, 18:23:

I suspect the SID is damaged and the SwinSID is borked as well. The fiest SwinSid worked fine. I sent that one out after the giveaway. What about your SwinSID, @matze79?

Unless the socket is damaged. You could put the SID back in and measure the address lines one more time. This time from the ISA edge connector to the SID's pins.

Well that’s a long stretch but I will try that.

Your SwinSID is fine,
i can send it back as i don`t need it anymore.
I got several now for testing with some other projects 😀