brostenen
Experienced Member
As people here are extremely helpful to NOOB's like me, with a rather technical question, then I have one regarding a SID chip in one of my 64's...
The symptoms are bad sound. As an example, then the title melody in the intro of winter games played back with glitches.
Other titles like Golden Axe, will have glitches here and there in the intro music track.
If I run a C64 diagnostic tool (the one that goes through all the chips and so on), then the everything is good except SID test.
If I copy PRG from my SD2IEC to tape, using a copy tool and save as "Turbo tape" then everything is good.
The voltage levels on the SID are 11.97 Volt between Pin28 (Vdd) and Pin14 (GND) and 4.75 Volt between Pin25 (Vcc) and Pin14 (GND).
Voltage levels does not go up and down, they are perfect stable with the values they have.
So it is not the 5volt line or anything like that that are unstable or something, nor the Ram or something like that.
Well... At least that is what I can logically conclude from these tests.
And if I run a ready coded set of lines that I found, called "SID Bench" were it goes through the chips registers and so on,
then the SID will not behave like it should. It is one of those that uses POKE commands and so on, and I am not a programmer by any shot.
So I am really not sure what the lines of code actually does, yet the SID craps out, and for what I know, the code writes the SID directly.
So is my amateur way of diagnosing correct, that it is the SID that are defect?
Thanks in advance
Brostenen
The symptoms are bad sound. As an example, then the title melody in the intro of winter games played back with glitches.
Other titles like Golden Axe, will have glitches here and there in the intro music track.
If I run a C64 diagnostic tool (the one that goes through all the chips and so on), then the everything is good except SID test.
If I copy PRG from my SD2IEC to tape, using a copy tool and save as "Turbo tape" then everything is good.
The voltage levels on the SID are 11.97 Volt between Pin28 (Vdd) and Pin14 (GND) and 4.75 Volt between Pin25 (Vcc) and Pin14 (GND).
Voltage levels does not go up and down, they are perfect stable with the values they have.
So it is not the 5volt line or anything like that that are unstable or something, nor the Ram or something like that.
Well... At least that is what I can logically conclude from these tests.
And if I run a ready coded set of lines that I found, called "SID Bench" were it goes through the chips registers and so on,
then the SID will not behave like it should. It is one of those that uses POKE commands and so on, and I am not a programmer by any shot.
So I am really not sure what the lines of code actually does, yet the SID craps out, and for what I know, the code writes the SID directly.
So is my amateur way of diagnosing correct, that it is the SID that are defect?
Thanks in advance
Brostenen
Last edited: