Search found 368 matches

by Gyro Gearloose
Sat Jan 16, 2021 6:02 pm
Forum: Hardware
Topic: With the vic-ii removed...does the floppy work?
Replies: 10
Views: 82

Re: With the vic-ii removed...does the floppy work?

Well, not really. An oscilloscope is "nice to have" but as you can see, in digital logic troubleshooting, all you really need to look for is "activity" vs. "stuck at 0 or 1". Some signals should be stuck, but most should be doing "something". There is a tool c...
by Gyro Gearloose
Sat Jan 16, 2021 1:24 am
Forum: Hardware
Topic: With the vic-ii removed...does the floppy work?
Replies: 10
Views: 82

Re: With the vic-ii removed...does the floppy work?

I sort of ignored my own advice: step by step. My usual process is verifying power supply, reset, then the clock circuit. The reset circuit keeps the 64 in reset for about half a second after you power it up, in order to give time for the power supply voltages to stabilize and the clock to stabilize...
by Gyro Gearloose
Fri Jan 15, 2021 6:03 pm
Forum: Hardware
Topic: With the vic-ii removed...does the floppy work?
Replies: 10
Views: 82

Re: With the vic-ii removed...does the floppy work?

A further thought occurs. The MOS branded support chips also fail regularly. Your version of the motherboard uses an 8701, as seen here https://www.breadbox64.com/c64-hardware/commodore-64/assy-250425-rev-a/ Any of these smaller ICs with the MOS logo should be on the list of suspects. If your 8701 s...
by Gyro Gearloose
Fri Jan 15, 2021 1:50 pm
Forum: Hardware
Topic: With the vic-ii removed...does the floppy work?
Replies: 10
Views: 82

Re: With the vic-ii removed...does the floppy work?

Chips aren't cheap if you look at the prices of VIC-IIs and SIDs.

What about the fuse? Did you connect anything to this 64 between taking it out of storage and it failing?
by Gyro Gearloose
Thu Jan 14, 2021 11:30 pm
Forum: Hardware
Topic: With the vic-ii removed...does the floppy work?
Replies: 10
Views: 82

Re: With the vic-ii removed...does the floppy work?

You have to be more precise, "react" could mean anything. If the 64 has an added hardware reset switch, you can press it and an attached 1541 will reset as well, but this is entirely a low-level hardware function that will work as long as there is power. A missing VIC-II won't change that....
by Gyro Gearloose
Thu Jan 14, 2021 7:24 pm
Forum: Hardware
Topic: With the vic-ii removed...does the floppy work?
Replies: 10
Views: 82

Re: With the vic-ii removed...does the floppy work?

My friend, the VIC-II doesn't only produce the display, it also refreshes the DRAM. So if there's no VIC-II, there's no way the 64, any model, can work. Essentially it would have no RAM. Even worse: the VIC-II also generates the clock for the CPU, so it doesn't matter if there's no RAM, there's no c...
by Gyro Gearloose
Mon Jan 11, 2021 7:56 pm
Forum: Hardware
Topic: Can I connect my C64 to a VGA monitor?
Replies: 3
Views: 78

Re: Can I connect my C64 to a VGA monitor?

That seems like a nice Trinitron monitor. It should work nicely with a ViewSonic unit.
by Gyro Gearloose
Mon Jan 11, 2021 4:39 am
Forum: Hardware
Topic: Can I connect my C64 to a VGA monitor?
Replies: 3
Views: 78

Re: Can I connect my C64 to a VGA monitor?

Not directly, but there are plenty of video scalers that can take a NTSC or PAL video signal and convert it to a VGA signal.

I recommend a ViewSonic unit like a N4 or the older VB50HRTV.

But what model monitor is this?
by Gyro Gearloose
Mon Jan 11, 2021 1:16 am
Forum: Hardware
Topic: 6510 question
Replies: 2
Views: 154

Re: 6510 question

Not sure I understand your reply. Locations $0000 and $0001 in the 6510 are mapped internally to the I/O port. Do accesses to those addresses generate external CPU bus cycles?

In any case it means that if you map the VIC-II to the first 16K, the 6510 can only write 16382 bytes there.

I feel cheated.
by Gyro Gearloose
Fri Jan 08, 2021 4:10 pm
Forum: Hardware
Topic: 6510 question
Replies: 2
Views: 154

6510 question

Since the 6510 uses addresses $0000 and $0001 for the 6 pin I/O port built into the chip, do accesses to these two addresses cause external changes on the external 6510 address and data lines? Like does reading or writing to these addresses generate a R/W cycle with the data ignored by the CPU? Does...