spindlenine

Dude, this thing sounds totally awesome - none of the demos I saw on YouTube did it any justice. Here's some photos of the build. http://www.flickr.com/photos/maximporges/sets/72157625643566528/ Cheers, - max

Thanks for the tip, Wilba. After you explained the way the encoder works, I ran the continuity test and found that pins 2 & 3 had constant continuity regardless of what was happening with the encoder knob, while pins 1 & 2 only beeped when I turned the knob. I flipped over the board and saw a little blob of solder on the connections for the smaller encoder (picture attached, blob outlined in blue). Since those connections are bridged with the ones for the larger encoder on the PCB, I had a constant connection between pins 2 & 3. I removed the solder and now it all works great. Here comes a beer for you! :) Cheers, - max

Thanks Wilba, I'll run these tests today and will respond with my findings.

Hey guys, Sorry in advance if this is answered elsewhere, but I looked around on the forum a bit and saw a few other people had bad encoders, but couldn't see any more specific details to help with my particular problem so I'm posting a new thread. So, I finished assembling my sammichSID last night and it all worked flawlessly the first time except for the rotary encoder, which I believe is dead to the world. No matter what screen I am on, nothing happens when I twiddle the encoder. Having looked at the manual it looks like the rotary encoder should flip through the screens and change values for selected items on the LCD. I've beep-tested the encoder to make sure that my traces and soldering are good, and although the joints seem to be fine, I'm not sure if the results I am seeing are correct. From the control surface PCB, I see that the board will take one of two different rotary encoder sizes. The encoder I have has three prongs on the bottom with the wide spacing, one prong on each side, and no prongs on the top. Following the traces, I see that my encoder only seems to have two traces that connect with the resistor network above the 74HC16 on the bottom right of the control PCB on pins 2 & 3; if I had the other encoder type that the board is made for, it looks like a third trace would run down from the top left prong to the resistor network on pin 4. When I beep-test my rotary encoder, all three prongs beep, but two prongs appear to be connected to the resistor network on pin 2 and one prong is connected to pin 3. I'm confused by the fact that the far right prong on the rotary encoder causes a beep on pin 2 of the resistor network since there are no traces connecting these two; the only answer I can think of is that my rotary encoder bridges the middle prong and the far right prong. None of the rotary encoder prongs appear to be connected to pin 4 on the resistor network. I have attached a photo with color-coded blobs to show where the connections are registering. Note that my resistor network is soldered very close to the PCB so I tested the connections against the 74HC16 pins that are passed through to by the resistor network. I was hoping somebody could help me with the following questions: 1) Are the connections the rotary encoder is making correct based on my tests? 2) Assuming they are correct, is it possible that my rotary encoder is bad? Is there any other testing I should do before I de-solder it? 3) Are there any further troubleshooting steps that are recommended in this situation? Thanks in advance for any assistance. I'm super excited to get this issue resolved and start playing with my sammichSID! - max

Thanks for pointing that out, nILS. As stated earlier, I'm a total electronics n00b so I could use a little help here. How should I be measuring the 9V rail? To be clear, the fuse is in the C64, it's powered on, and I'm measuring across the fuse.

Yeah, I was looking at the SID kits tonight thinking the same... :) I'd have to build a core module, a midi input module, and a SID module though wouldn't I?

Hmm, a potential new development following the earlier testing. I plugged my headphones in to my Mac (running the C64 through an Elgato EyeTV as before), and when I run sound programs on the C64 I am hearing a difference in tone, but not a musical tone akin to what I am expecting. I'm using the sound program that is on page 80 of the C64 user guide. When the sound program is not running, the C64 makes a humming noise, almost like a chorus. When I run the sound program, the humming goes away and I get a constant, faint, high-pitched noise. When I stop the program, the humming chorus noise returns. Here's an MP3 of what I am describing. Right around the 2 second mark I start running the program, and then at the 7 second mark I stop it. Any ideas what this means? I'm guessing that the SID chip is broken in some way. Would you guys think it's safe to try one of the other SID chips that I have in my possession?

I finally got some time to run the tests you guys suggested. Here's the results. 1) I bought a cheap chip extractor and pulled out the SID chip from the C64's board, then powered on the board with the SID out and put a multimeter to pins 14 and 28 of the empty socket. I got a reading of 11.82V, so it seems to have the right voltage going through (12V being the expected amount). 2) I tried checking the 9V rail. With the C64 powered on, I put my multimeter across the fuse with the meter set to VAC. I got a reading of 0.022. When I pulled the fuse out, it passed the "beep" test on the multimeter, and the wire inside the fuse is intact. Does the reading on the 9V rail seem low to you guys? Shouldn't I be getting 9VAC there? Does this indicate a possible problem with the 9V rail? Thanks, - max

Wow, you guys are awesome. Let me work my way through the responses one by one. I can get static noise from the EyeTV when I disconnect the RF adapter, and get noise when it is plugged in and I touch the exposed screw terminals with my finger. When hearing this static, if I turn down the volume on the EyeTV, the static is muted. Would you say that's a good enough test? Duly noted. It sounds like this power supply and associated innards from the C64 will be usable for the MB6582 then, even if the SID chip in the case is dead. This I would love to do, seems like a logical next step. I'm not sure exactly how to do this though. From the diagram on http://en.wikipedia.org/wiki/MOS_Technology_SID, my guess is that GND and VDD are the pins I want to use for positive and negative with my multimeter respectively? How many VDC should I expect to see running through the chip (12VDC, I'm guessing)? Will the power be flowing regardless of whether or not the chip is making noise? Also, I see that there is an audio out pin. Is there a way I can run a sample sound program while holding the multimeter to the chip to see if audio is exiting the chip but perhaps not making it to the outside world? Thanks - also noted. I'll go get an IC puller from Radio Shack or Skycraft here in Orlando, FL. I think I saw your post on this elsewhere (or somebody else with the same idea). I looked at the fuse yesterday. It has a twisted wire within and appears to be intact. To test this fuse, I'm guessing I just need to turn on the C64 with the case open and hold my multimeter against both ends, expecting to see 9VDC? Sadly, I have no Datasette. Sadly, I have no Datasette to test this theory. Is it possible to put my multimeter against some of the pins of the socket the Datasette uses to see if any current is flowing? Something else I noticed is that every C64 I have seen dismantled online has a metal casing over the motherboard. This one did not have the metal casing over the motherboard - I popped open the case and the motherboard was exposed to me bare. Any concerns with this anomaly? Lastly, the motherboard is still really dusty. I can't see any harm in giving it a gentle blast with compressed air to clean it off. Any words of warning here? Again, thanks so much for all the tips! I'm looking forward to getting to the bottom of this and will post my results once I know how to test the chip.

Hello all, In my quest to work my way up to building an MB6582, I have been sourcing SID chips and an old C64 to yank some parts from. I just got one of the two SID 6581s that I bought off eBay in the mail, along with an old C64 that also has a 6581 inside. I was hoping to use the C64 to test any SID chips that I buy. However, the C64 doesn't seem to make any sound. I hooked it up to my Mac with an Elgato EyeTV adapter, and I get video, but no sound. I know that sound is coming through the EyeTV since if I pull out the cable I get static noise with the fuzzy TV signal, and when the cable is connected I can touch the screw terminals on the RF adapter for the C64 and hear static hum as well while the video picture slightly distorts. I tried to make the C64 make some noise by typing in the BASIC sound program in the C64 manual, but it doesn't make any noise at all. I cracked open the case and there is definitely a SID chip in there alright, it just seems to be quiet. The motherboard was covered in dust, so this thing has obviously been around a while. So, here are my questions for you guys. 1) Is it likely that the SID chip is just dead? I looked around a bit on the web and it seems like 6581s are more susceptible to untimely death than 6582s. Is there any way to test the SID chip while the C64 is powered on besides handing BASIC programs to it? I have a logic probe and a multimeter, although I'm a relative beginner with electronics so please be gentle with any suggestions. Any other suggestions for checking the chip in situ? I have another SID chip that is supposed to work that I could plug in to the socket in the C64, but two things are preventing me from wanting to do so. 2) The first that worries me is that the power supply I received with the C64 describes itself as "5VDC 7.5VA" and "9VAC 9.0VA", but I've read on the forums that the 6581 is supposed to take 12VDC. I'm not really sure how to interpret the label on the power supply - is it the correct one? 3) The second thing that worries me about testing my other SIDs in this C64 is that if the one in the case is dead, I'm scared that maybe a malfunction in the C64 itself killed it. FWIW, everything else seems to be working. Should I be worried at all about putting my other SID chips in on this board? If the answer is to yank the existing SID from the C64 and try the other one, any tips on the best way to yank the old chip out and put the new one in without damaging anything would be appreciated. It looks like you just pull it out gently with pliers, but I figured I'd ask the experts first. Many thanks in advance for any help you guys can offer me! Cheers, - max