Denial

audronic1 wrote: ↑Tue Jul 11, 2023 5:31 pm Hi Simon
Thanks
I have ordered 1 (Vic-20 Vic Chip) from England (EBay)
Keep Safe
Ray

The Vic-20 Vic Chip arrived from England and I was Pleased That the Donor Board Now WORKS
The Computer Passed all the Dead test Cart Tests
Thanks to all who have offer some repair information
keep Safe
Ray

Hi Simon

Thanks

I have ordered 1 (Vic-20 Vic Chip) from England (EBay)

Keep Safe

Ray

Lechuck wrote: ↑Tue Jul 11, 2023 5:12 am Hi Audronic,

I did it using the diagram I attached to your other post and worked ok for me. Have you used the same diagram?.

Hi Lechuck

I have used a " VIC-20 CHR ROM REPLACEMENT" PCB which is known to work

Keep Safe

Ray

If you perhaps add a schematic of how you wired the pins of the 2764 that would help to assess what probably went wrong. The mainboard uses VA12=VA13=0 for the two chip selects of the original character ROM, mapping those to /CS and /OE of a 2764 works the same way as with a 2732, regardless whethe...

Hi All

Have been making up a Character Rom Replacement for a Vic-20

Using a 2764 Eprom. But I am unable to get it to work
If I Use a 27C32 eprom this works. Is this normal

What do most people use ??

Thanks

Keep Safe

Ray

Hi All - Doug Thanks It turns out to be the Vic 6561-101. After desoldering and replacing it with a socket and used my VERY Suspect Vic Chip It now works as do the other 2 Vic-20s that I have been working on. A Small request :- Where can I get 3 Vic 6561-101 chips. I am in Victoria Australia. Thanks...

That looks like a faulty BASIC ROM. To test if it is without desoldering, if you have any game cartridges then boot with one inserted, and if the game runs then BASIC is faulty. Note, this only works with a cartridge that boots directly at start-up (ie not a Scott Adams adventure) Hi Doug I have tr...

Hi All I have been given a Donor board to help with repairing an other Vic-20 BUT This is all I get on the screen (See photo) I have removed the Kernal Rom and fitted a socket tested it in an other Partial operating Vic-20 and it tests ok I have been over the Motherboard and am Stumped. Any help wou...

Hi All Thanks for your help I am Nearly finished Just have to find a Vic chip 6561 and away we go The fault turned out to be a 14 Ohm earth connection on U14 (6116). Due to a Poor socket replacement (NOT MINE) The Vic Chip is very unwell BUT with the Penultimate + Cart I was able to see what's going...

Hi Mike

I have repaired the Mess with a range of "Bodge Wires"
Unfortunately it has not fixed the Problem

I wanted to check if the Character rom I have is Ok ??
So to do that I need an other Proven replacement.
Thats why the enquiry

Keep Safe

Ray

Hi All I dragged The Vic-20 out again and removed a socket the had been "PREVIOUSLY" fitted and to my amazement this is what I found? (Place rude word here) PS:- There are 2 other sockets also that had been previously added ???? No wonder the Poor old Vic-20 was unwell. I will work on this...

Hi All

Does anybody know if this works for the Character ROM (2332 - 2732) for the VIC-20 ?

Photo Below

Keep Safe

Ray W

@Mike I have tried removing both Via's no change BUT the vic chip has gone down it no longer works I had a Donor board which I fitted Dual Wipe sockets to ( Yes the Whole board) and I don't have enough working chips to go any further Still waiting for Character rom eprom adapter to arrive to elinmin...

srowe wrote: ↑Sun Jun 18, 2023 6:34 am

audronic1 wrote: ↑Sun Jun 18, 2023 6:32 am I will connect a keyboard.
as I am New to Vic 20's I don't know of any pokes yet
If you can help with the pokes that would be appreciated

Try just

Code: Select all

POKE36878,15
POKE36875,200

@srowe

The pokes did not work , also changed the 6522s over still no output.

Thanks

Keep Safe

Ray W

You seem to get as far as the VIC chip initialization since you have something displayed with the correct number of volumns and rows. If you type on the keyboard, does the screen change in any way as a response? You could try poking to change the border color or start a sound to see if only the dis...