Picture but no sound!

MrPagel · December 29, 2010, 03:37 AM

I recently acquired a C128. It worked great for about a week, but now there is no sound other than a loud BUZZ. The buzz only occurs when the audio cable is plugged into the monitor, so I don't think the monitor itself is the problem. Picture is fine, and there are no other problems I know of. But there's no sound other than the buzz.

Any ideas?

RobertB · December 29, 2010, 12:17 PM

Failed SID chip?

Just outputting buzz now,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
The Other Group of Amigoids
http://www.calweb.com/~rabel1/
Southern California Commodore & Amiga Network
http://www.sccaners.org

MrPagel · December 29, 2010, 12:43 PM

Well, I hope it's not the SID. If it were, would it make a big loud buzz all the time, not just when it's supposed to be making sound? It sounds like a 60hz ground loop hum.

I do have an "extra" c64 which doesn't work, so I should be able to use it for "spare parts." Since I want to use this machine primarily for music, it would be awfully nice to get the sound back online.

(I'm a composer who'd like to throw his hat into the "8-bit music" ring...)

RobertB · December 29, 2010, 02:53 PM

Quote from: MrPagel on December 29, 2010, 12:43 PM
Well, I hope it's not the SID. If it were, would it make a big loud buzz all the time, not just when it's supposed to be making sound? It sounds like a 60hz ground loop hum.

Well, another possibility would be your connections and/or your a/v cable. Have you tried wiggling the cable and checking out the ends of the connectors?

Quote(I'm a composer who'd like to throw his hat into the "8-bit music" ring...)

That would be good, especially if you compose tunes to be released into competition, like for the PixelJam demoparty at the April 14-17 Notacon in Cleveland, Ohio.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
The Other Group of Amigoids
http://www.calweb.com/~rabel1/
Southern California Commodore & Amiga Network
http://www.sccaners.org

MrPagel · December 29, 2010, 03:07 PM

I have checked the cable, and wiggled it around a bit, and sometimes the buzz gets a little louder or softer, but that's it (this does make me think it's a connection issue). Sadly, I don't have another cable at hand to try. I have a C64 cable, but it looks like it has a different pin configuration.

I should mention that the last thing I did before this trouble started was to try to connect the RCA plugs into an adaptor so I could plug it into a mixer. When I realized I didn't have the right adapter, I plugged it back into the monitor, and that's when the trouble began.

Regarding composing, I haven't heard of those particular competitions. I bet those are for purely "chiptune" works -- I'm not enough of a programmer yet to get the music I have in my head to come out of the Commodore without using some editing software on my PC. I also want to use my Moog synthesizer for it as well. (Wouldn't a Moog/C64 duet be fun?)

Thanks!

RobertB · December 29, 2010, 03:30 PM

Quote from: MrPagel on December 29, 2010, 03:07 PMI have checked the cable, and wiggled it around a bit, and sometimes the buzz gets a little louder or softer, but that's it (this does make me think it's a connection issue).

Yes, it sounds more and more like a connection problem.

QuoteI should mention that the last thing I did before this trouble started was to try to connect the RCA plugs into an adaptor so I could plug it into a mixer. When I realized I didn't have the right adapter, I plugged it back into the monitor, and that's when the trouble began.

I hope you did that with all power off on the Commodore. If not, the act of connecting the sound cable "hot" could send a feedback into the Commodore and destroy the SID chip.

QuoteRegarding composing, I haven't heard of those particular competitions. I bet those are for purely "chiptune" works -- I'm not enough of a programmer yet to get the music I have in my head to come out of the Commodore without using some editing software on my PC.

If you are more musician than programmer (who would use music trackers), then Cynthcart from Atariage.com comes to mind. With Cynthcart, you could play live by pressing on the Commodore keys (and Cynthcart does chords, too). The only problem is that Cynthcart does not save, but I don't see it as a big problem, because you can feed its audio signal into an audio recorder or computer.

QuoteI also want to use my Moog synthesizer for it as well. (Wouldn't a Moog/C64 duet be fun?)

There was the Moog Song Producer MIDI interface for the C64.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
The Other Group of Amigoids
http://www.calweb.com/~rabel1/
Southern California Commodore & Amiga Network
http://www.sccaners.org

MrPagel · December 30, 2010, 03:24 AM

Oh, well OF COURSE I did it with the power ON. Stupid stupid stupid! So I guess that's probably what did it.

As I said, I do have a 64, which should have a SID that I could swap out, right? Well, I have to get someone else to do it, actually... obviously, I tend to turn things like that into a disaster. Even much much simpler things.

Anyway, this is useful information. Thanks much! I'll let you know how it turns out.

Hydrophilic · December 30, 2010, 12:16 PM

Lot's of love, my friend has C64c with same problem. We tried swapping cables but still no sound, so his SID is probably fried too. We haven't taken it apart yet to see what kind of SID he has.

You can swap SID chips if they are the same part#. The original SID is a 6581 used in original C64 and flat C128s. At some point, CBM switched to from NMOS to HMOS-II and the SID became the 8580. I think these are in the C128D and later C64c models. So check to be sure.

Different versions should not be swapped because the original uses +12V while the later uses +9V. If they are the same, then go for it!

MrPagel · December 30, 2010, 01:59 PM

So, questions, before I crack the thing open:

Is there a way to be sure that it's the SID, and not some other issue... I'm still wondering if it isn't a bad connection, or could it be a bad fuse?

Will I be able to look at the SID and know right away, "oh, yeah -- this thing's fried."

How delicate is this operation? I assume we're talking soldering, right? Do I want to be doing this myself, or should I find someone with experience?

AND... living out here in Fumbuck, Wisconsin, is there a way to find like-minded geeks who would be able to help?

Thanks again! I was REEEALLY into some fun programming when this happened... just sickening.

RobertB · December 30, 2010, 03:59 PM

Quote from: Hydrophilic on December 30, 2010, 12:16 PMAt some point, CBM switched to from NMOS to HMOS-II and the SID became the 8580. I think these are in the C128D and later C64c models.

Correct.

QuoteSo check to be sure.

Different versions should not be swapped because the original uses +12V while the later uses +9V. If they are the same, then go for it!

Yup, I agree.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
The Other Group of Amigoids
http://www.calweb.com/~rabel1/
Southern California Commodore & Amiga Network
http://www.sccaners.org

MrPagel · December 30, 2010, 04:16 PM

I just discovered that the game "paddles" (not the joystick) do not work, and they were also used by the SID chip, right? So I bet it must certainly be the SID that I fried.

Where can a fellow get a new SID chip? Does anyone in this forum sell them? Are they cheaper than just buying a new computer?

MrPagel · December 30, 2010, 04:21 PM

(...By the way -- the reason I know about programming paddles is that I had used them with the C128 to make a sort of "virtual theremin." I used one paddle for pitch, and the other for pulse width, filter or ring modulation. It was beyond awesome!)

RobertB · December 30, 2010, 04:40 PM

Quote from: MrPagel on December 30, 2010, 01:59 PMIs there a way to be sure that it's the SID, and not some other issue... I'm still wondering if it isn't a bad connection, or could it be a bad fuse?

A bad connection is still a possibility, but to test that out, you'd have to have another, known-working a/v cable. It would not be a bad fuse, because the computer wouldn't work at all.

QuoteWill I be able to look at the SID and know right away, "oh, yeah -- this thing's fried."

No, a dead SID looks like a good SID (unless the dead SID had burn marks on it).

QuoteHow delicate is this operation? I assume we're talking soldering, right? Do I want to be doing this myself, or should I find someone with experience?

If your parts machine has a socketed SID and your C128 has a socketed SID, you are all set; all you'd have to do is unplug the parts machine, good SID with a chip puller/small screwdriver/pocket knife, do the same operation with the dead SID from the C128, and then push the good SID into the C128 socket. However, if your parts machine and/or C128 have soldered-in SID chips, then you'd have to desolder the chips, install a socket into the C128, and then push in the SID into that socket. If you can't perform this operation, then you'd have to find someone who can do it.

QuoteAND... living out here in Fumbuck, Wisconsin, is there a way to find like-minded geeks who would be able to help?

I'm not sure if the Madison Area Commodore User Group is still around; however, there is a website/forum devoted to those classic computer users in Wisconsin. Go to

http://www.8bitclassics.com

The treasurer of MACUG used to be Brian Strang. If this e-mail is still good, contact Brian at

strang(at)chorus.net

Perhaps he can help or lead you to someone who could help.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
The Other Group of Amigoids
http://www.calweb.com/~rabel1/
Southern California Commodore & Amiga Network
http://www.sccaners.org

RobertB · December 30, 2010, 04:50 PM

Quote from: MrPagel on December 30, 2010, 04:16 PMI just discovered that the game "paddles" (not the joystick) do not work, and they were also used by the SID chip, right?

Yes.

QuoteSo I bet it must certainly be the SID that I fried.

Where can a fellow get a new SID chip?

Well, new ones are almost impossible to find, but used ones are available.

QuoteDoes anyone in this forum sell them? Are they cheaper than just buying a new computer?

Truly,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
The Other Group of Amigoids
http://www.calweb.com/~rabel1/
Southern California Commodore & Amiga Network
http://www.sccaners.org

RobertB · December 30, 2010, 05:03 PM

Quote from: MrPagel on December 30, 2010, 04:21 PMI used one paddle for pitch, and the other for pulse width, filter or ring modulation. It was beyond awesome!

Hmm, the Cynthcart for the C64 can use a paddle to "bend" the notes during live play. I've seen 8-Bit Weapon do this in concert. He plays the Commodore keyboard while another is on the paddle bending notes. This can be seen at

http://blip.tv/file/1774972

Truly,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
The Other Group of Amigoids
http://www.calweb.com/~rabel1/
Southern California Commodore & Amiga Network
http://www.sccaners.org

MrPagel · December 30, 2010, 05:27 PM

That sounds very cool. What I did was, since there are 2 paddles connected, I used one to "sweep" the pitch on the hi-freq oscillator, anywhere from 0-255, and the other to control other effects. Or, with just one paddle, use the fire button to turn sound on/off. I also had a second voice harmonized with the first. It was all in BASIC, and the program was only a few lines! Commodore machines are THE BEST.

Then, of course, I blew the sound chip....

RobertB · December 31, 2010, 05:01 PM

Quote from: MrPagel on December 30, 2010, 05:27 PMWhat I did was, since there are 2 paddles connected, I used one to "sweep" the pitch on the hi-freq oscillator, anywhere from 0-255, and the other to control other effects. Or, with just one paddle, use the fire button to turn sound on/off. I also had a second voice harmonized with the first. It was all in BASIC, and the program was only a few lines!

Oh, that's very interesting. You'll have to post a listing of the program.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
The Other Group of Amigoids
http://www.calweb.com/~rabel1/
Southern California Commodore & Amiga Network
http://www.sccaners.org

MrPagel · January 09, 2011, 09:55 AM

Okay, so I got a new C64 to replace the 128. Works okay, but it tends to flicker and black out -- black screen, no response -- intermittently. Also, the background hum is pretty loud. A little research has suggested that this may be a power supply issue. I am wondering if I can use the power supply from a (newer) Commodore 64C?

The original brick reads:
INPUT: 117V 60Hz 40W
OUTPUT: 5VCC 7.5W 9VAC 2.5VA

The new one reads:
INPUT: 117V 50/60Hz 40VA
OUTPUT: 5VDC 7.5W 9VDC 6.7VA

Will this new power supply kill my breadbox?

RobertB · January 09, 2011, 04:33 PM

Quote from: MrPagel on January 09, 2011, 09:55 AM
I am wondering if I can use the power supply from a (newer) Commodore 64C?

Yes, you can.

QuoteWill this new power supply kill my breadbox?

If this newly-received power supply is failing, too, then yes, it can kill the C64.

FCUG celebrating 30 years,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug