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Cbm 2001 Pet strange boot

So, that looks OK. I don't specifically know about the data bus though - but at least there are no "NO SIGNAL" pins!

Can you now swap the original ROM in UD9 for the abracadabra ROM and repeat the UD9 pin testing please.

Dave
 
Abracadabra rom on Ud9:

1 to 9: L
10: H
11: L
12: L
13: L
14: L
15: H
16: L
17: H
18: L
19: L
20: L
21: H
22: L
23: L
24: H
 
That looks promising...

Let me check the data value that is being returned... YES = $A2 (1010 0010).

So, can you now see the same value on the data bus pins of the CPU socket?

Dave
 
Excellent.

So, there has to be something wrong with that EPROM you were using...

NO: Not bad video RAM - where did you get that from?

Can I suggest removing the bits of wire now from the CPU socket and putting the CPU back in?

Dave
 
daver2 said:
Excellent.

So, there has to be something wrong with that EPROM you were using...

NO: Not bad video RAM - where did you get that from?

Can I suggest removing the bits of wire now from the CPU socket and putting the CPU back in?

Dave
Click to expand...
Ok now i have abracadabra eprom on ud9 and cpu on board!
 
Well, does it work - or are you still desperate?

If it doesn't work - check CPU pin 7 (SYNC) and the outputs from UD2 for pulsing activity. Both using your logic probe.

Dave
 
>>> with original rom 901465-03 on Ud9 i have always low signal

That's not what I said. Did you put ALL of the original PET ROMs back in?

Dave
 
daver2 said:
>>> with original rom 901465-03 on Ud9 i have always low signal

That's not what I said. Did you put ALL of the original PET ROMs back in?

Dave
Click to expand...
All roms on board but i have again low signal on Cpu pin 7
 
what type of eprom should I select on the programmer to be able to read the original roms?
 
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