Denial

That's a wide range of problems. I think you should check your power supply first. Buy a cheap multimeter if you don't already have one, then test the 5V line. Measure both DC and AC volts on the 5V line. If the power supply is 'smooth' enough there should be almost no AC voltage. Does this trouble ...

I still have no clue what you would do with a speech synthesizer except play with it. It's funny you should say that, since the first page of the owner's manual says: "Enjoy using a fun product and by all means let us know if you develop any innovative applications in the home environment.&quo...

After searching the forums, I came across several old threads where people have talked about speech synthesiser cartridges for the VIC-20. As far as I could tell, nobody ever uploaded any audio or video demonstrating it, so now I have: https://youtu.be/w9fIe_2RRgg Audio download (6MB mp3): https://1...

Indeed, based on your description it sounds like your VIC has the case and keyboard of a made-in-Japan unit like mine and the motherboard of a later 'CR' model with the DIN power connector. So I agree with your assessment. I hope you enjoy using your new toy! That similar-looking VIC-20 of mine is a...

One of my VIC-20s also has the PET-style keyboard, silver label and no yellowing on the case. It was made in Japan, has mid-1982 date codes on the chips and the serial number 533475. Where does your case say it was made? I think both time and location of manufacture lead to the various differences w...

How big is the LCD? I usually use a 13" CRT TV or a small-medium LCD TV with the composite output and it looks fine. Certain colours tend to be a bit worse though, especially green, red and magenta in my experience - this is where the S-video mod will help by properly separating the luminance a...

It sounds like the textbook author could have invented those terms. I'd suggest that it's basically a shorthand way of saying the 8080 has more registers and the instruction set is geared more towards doing operations on the registers; while the 6800 has only two accumulators and one index register,...

Thanks again for that, now I know what to look for!

Thanks for your patient suggestions MCes, but unfortunately I can't do either of those things. I can't rotate those parts by 180 degrees because they only fit one way round.
I'm going to partially dismantle the keyboard again today, to see if there was anything I missed.

The underside of the repaired PCB: https://farm5.staticflickr.com/4761/28140167879_00555e96a9_z.jpg The problem with the F7/F8 key: https://farm5.staticflickr.com/4751/28140166899_c5587454c6_z.jpg Note the bump on the left side of each white plunger and the corresponding slot in the black stalks. Th...

I can take the keyboard off the case for the photos but do you also need me to open up the keyboard itself? If you could lift off the F7 key and the black stalk underneath and photograph that, so I can see how the white plunger is supposed to fit, that should help I think. MCes, I'll post a couple ...

Thanks, eslapion. That should be a great help!

No problem at all.
I'm currently studying to be a high school teacher myself, I look forward to getting started in a couple of years!
And thanks

Then where is the 1Mhz clock?. srowe's link gives the answer: NTSC machines have a 14.31818 MHz crystal oscillator, which gets divided by 14 to produce the 1.022727 MHz clock while on PAL machines it's a 17.734475 MHz crystal divided by 16 to give a 1.108404 MHz clock. These odd frequencies are req...

#3: how many VICs where sold? I don't know, but I do know that it was the first computer ever to sell 1 million units. #4: What is the speed of the tape drive? (Ex: 200 Bits per second) I think it's roughly 300 baud (bits per second). This slowness contributed to the high reliability of Commodore's...