Vic20 Startup sequence to main screen Display? (was: Help Cartridge with a startup SOUND)

[Mike]

Keyboard does not show any change no matter what I press on the keyboard [...]

While bjonte suggested trying "blind input" from what was known with your start post, from the point you provided the screen shot with the garbled characters it was quite clear that chances to get a positive result from that were very slim: if the KERNAL manages to set the VIC registers (as evident from the correct display window dimensions), but furtherhand does not manage to clear the screen, the KERNAL is stop-tracked in the middle of the reset routine long before it enters the READY prompt. The latter however would be the requirement to be able to enter BASIC commands and let them be executed after pressing the RETURN key.

As srowe pointed out, everything regarding the chip select logic might be the culprit.

[...] I also swapped the 6522s over no change.

There have been recorded cases where the VIAs produced unwanted continued interrupts and then "crashed" the computer. By removing the VIAs, the reset routine then at least could continue up to the point the computer produced the start-up prompt (but of course no working cursor and keyboard input). What happens if you remove both VIAs?

[audronic1]

@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 elinminate the Character rom

They have been put away until I get some spares.

Does any body have a schematic of an Eprom board to suit a Vic 20 character rom with 2 enable active pins ??

Thanks
Keep Safe

Ray W

[audronic1]

Hi All

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

Photo Below

Keep Safe

Ray W

[audronic1]

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 later today

Keep Safe

Ray W

[srowe]

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.

Ouch, that's some nasty damage.

[Lechuck]

Hi All

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

Photo Below

Keep Safe

Ray W

Hi Audronic,

not sure about 232->2732 adapter, but sometime ago I prepared the following to replace the VIC 20 Character ROM using a 27C64 EPROM, that was still easy to find.



With that I was able to replace the Character ROM.

Cheers

[Mike]

Does anybody know if [swapping pins 18 and 21] works for the Character ROM (2332 - 2732) for the VIC-20?

Yes, it does - see here.

I'd think though repairing the traces around UC4 should be given priority.

[audronic1]

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

[audronic1]

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 on.
See Photo below

Thanks Again

Keep Safe

Ray