Well, sorta glad to know that the sticky power switch is a common problem. I've not heat-sinked any of the chips in the Vic20... my C64 however, there's plenty to heat-sink in there... CPU, Video, PAL, Sound chips, etc.... and the voltage regulators too.

One of the things I did some years ago (on the Vic20) was wire up a stacked pair of 28-pin sockets to replace the ROMs with standard Atmel EEPROMs. I just burned the kernel and basic ROM code into them, it reduces the current by a fair margin overall. I also yanked all 5KB of RAM plus the 74HC138 decode chip and replaced all of it with a single 8KB static CMOS RAM... it yielded 6656 bytes free of course and eliminated 10 chips (2114s, 1024x4-bit) that draw a fair amount of current. I did layout a PCB set that can replace the ROMs and RAM chips, but haven't had a set made yet. Perhaps someday when I continue some other project stuff with the Vic20.

_________________
Regards, KM
https://github.com/floobydust

Thanks. I just remembered I had the size turned up a bit. If I press <Ctrl> - three times to get a picture in, the font goes down to about 7-point which is a bit small to read comfortably from three to four feet away which is the usual on my messy desk where the phone and other stuff is in the way. LOL


Is that the old Commodore 64 monitor? I gave a few of those away a few years ago. In DOS, I used to use 1024x786. (Most people probably didn't know you could do that in DOS, thinking only 640x480.)

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Nice mods. I only heat sinked the VIC that is driving this project, as I know it will be seeing hundreds of hours of run time. I a normally a stickler for keeping things pristine, but in this case I figure the heat sinks were acceptable. All of my other VICs are non modified with the exception of loosing the lid on the video cage. I have been stock piling parts to keep my VICs running for the rest of my natural life... roms, regulators, boards, etc. I now have 11 VICs in my possession as well, 9 of them in 100% working order. That should keep me solid for the life of the JetPack project!

I started an FPGA replacement for the 6560 at one point as well, but decided to drop everything but this project so that it actually makes it to completion.

Brad

I hear ya on that one! I have crazy good short sight (can do SMD with no glasses, even solder a 144 pin TQFP), but anything beyond my arm is in the "fuzzy zone". Even on my 24 inch monitor, I open this form full width, so my 1280 pics didn't seem too bad! The 1024 should be just about right for those with normal eyes!

Yep, that is the 1702 in the photo I posted with the VIC-20.
I wish I could round up one or two more, but shipping here is crazy expensive.
For this project, I am only allowing era appropriate peripherals... no flat panels doing NTSC!
Anything other than a glass CRT seems to steal the magic for me.

Brad

Ahem...that "best selling home computer" would be the C-64.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

Hi Brad, nice to have you back in the forum.


Aww... I'm still looking forward to seeing something like a TTL based DVI\HDMI interface someday.

Using breadboards is kind of amazing... My instinct would be to build small module PCBs and test them individually, then connect those into a larger system, but your way is more flexible and looks incredible.

You must be referring to that VIC-40 / TOI prototype that Team Terakura are currently working on.
That beast will never make it to the market once Tramiel sees my JetPack working!
VIC-20 will be the greatest home computer for decades to come... you shall see!
1982 will be owned by VIC.

Brad

Thanks! It feels good to be back here working on another monster project.

Brad

The Level Translating Expansion Port Buffers are now wired up.


TTL to CMOS ready IO buffers.

JetPack will require the same IO lines as any 6502 project, Address, Data, and R/W.
On the VIC-20, I PH2 is not required as it is already qualified as VRW.
BLK1,2,3,5 are required as the VIC breaks memory into 8K segments.
IO2,3 will be used for special functions such as Frame Sync and Joystick reading.

Here is the schematic of what I have wire up now.


VIC-20 to MOAB Level translating IO Buffers.

Since this is a real project, schematics will always follow each successful segment.
No doubt, there will be adjustments over the course of the entire build.

Later,
Radical Brad

Build first, schematic later.

That's the spirit!

Indeed!
My normal workflow usually doesn't include any schematics.
The only part I usually calculate is propagation delays.
Since I plan on rewiring the final version on a hand made PCB, schematics will be good!

Brad

Great to see this Brad! Looking forward to the thrills and spills of this build. Cheers.

_________________
C74-6502 Website: https://c74project.com

Just to make sure my IO buffers were working, I added a 32K SRAM chip for testing.
This is not the final position for the SRAM, so the wiring ain't pretty!


32K SRAM added to expand the VIC-20 Memory.

The VIC turned on, and displayed the expected expanded memory message.


24K along with the internal 3.5K available for Basic.

Total expansion memory is actually 32K, but VIC basic can only see an extra 24K.
I tested all memory by writing and reading to all locations.
The IO buffers are now considered working.
The more complex stuff will soon begin.

Cheers,
Radical Brad

Very nice start... however, I'm just wondering... any particular reason you didn't simply run the V/RW line directly to the Dir pin on the databus 245 transceiver versus running it through another 245 first? I can see having a buffered line to your bus, but not switching the databus direction through an additional delay.

_________________
Regards, KM
https://github.com/floobydust