Denial

For future reference, this is what PIN 3 output (LUMA + SYNC) should look like on a healthy 6561:

BASIC welcome screen, one frame @ 2ms/div:



Detail of vertical sync @ 100µs/div:

Quick note to let you guys know that I've got a replacement 6561-101 from Aliexpress. Just got it in the mail and my VIC-20 is back to life!!

I tried adjusting the trimpot to no avail. Also note that the last shots I posted were directly out of pin 3, ie. luminance + sync BEFORE mixing with color info so the actual signal out the DIN connector has a lower Vpp. I ended up ordering a new VIC. I think the fact that the VSYNC is missing and t...

Small update: today the VIC behaved differently and displayed this: http://i.imgur.com/DTFWIIql.jpg Which means now there is HSYNC but the screen still moves downwards so VSYNC is somehow missing. While on that state, I'm also able to change BOTH the background and foreground colors by poking 36879....

Hello everyone! I'm new to the forum. I recently bought a bargain VIC-20 which, as expected, doesn't work. The VIC-20 was my first computer so it has a special sentimental value for me, as it surely does for many of you. The board is a 250403 (VIC 6561-101). Here is the video output I get: http://i....