Pet 8296D no signs of life

[daver2]

Excellent...

So, where do we go now?

Dave

 

[Desperado]

I don't understand why the two romS are missing in UE9 and UE10

 

[Desperado]

Excellent...

So, where do we go now?

Dave

Maybe d0 to d7 on Cpu??

 

[daver2]

Spot on my friend!

Look for signs of healthy signals (first with the logic probe and then with the oscilloscope). Good TTL TRUE and FALSE levels with the oscilloscope.

All of the data lines should be oscillating nicely - with none 'stuck'...

Dave

 

[Desperado]

Spot on my friend!

Look for signs of healthy signals (first with the logic probe and then with the oscilloscope). Good TTL TRUE and FALSE levels with the oscilloscope.

All of the data lines should be oscillating nicely - with none 'stuck'...

Dave

ok thanks, directly on Cpu, right?

 

[daver2]

Yep.

Dave

 

[Desperado]

With logic Probe

CPU pins:
33 LOW
32 HIGH
31 LOW
30 HIGH
29 LOW
28 HIGH
27 HIGH
26 HIGH

 

[daver2]

Bummer, we fell into the same trap again didn't we!

We have the NOP generator in!

Monitor the data lines on a ROM then...

Dave

 

[Desperado]

We have the NOP generator in!

Yes i have Nop inserted

 

[daver2]

Monitor the data lines on a ROM then...

Dave

 

[Desperado]

Monitor the data lines on a ROM then...

Dave

ok which rom?

 

[daver2]

Any...

All of the ROM data lines are connected together...

Dave

 

[Desperado]

Any...

All of the ROM data lines are connected together...

Dave

Ok, so UE8 pins 9-10-11-13-14-15-16-17 pulsing!

 

[daver2]

So, we have gleaned as much as we can from the NOP generator.

So, where do we go next?

Dave

 

[Desperado]

So, we have gleaned as much as we can from the NOP generator.

So, where do we go next?

Dave

I suspect that i need to replace the missing roms...

 

[daver2]

What missing ROMs? There are no missing ROMs!

Check the schematics and you should observe that UE10 is address $9xxx and UE9 is address $Axxx. These were the OPTION ROM sockets in the PET for additional ROMs.

UE8 is the EDIT ROM ($Exxx) and UE7 is the BASIC and KERNAL ROM ($Bxxx, $Cxxx, $Dxxx and $Fxxx) all packed into one large ROM.

No missing ROMs here.

Think again...

Dave

 

[Desperado]

What missing ROMs? There are no missing ROMs!

Check the schematics and you should observe that UE10 is address $9xxx and UE9 is address $Axxx. These were the OPTION ROM sockets in the PET for additional ROMs.

UE8 is the EDIT ROM ($Exxx) and UE7 is the BASIC and KERNAL ROM.

No missing ROMs here.

Think again...

Dave

Ahhh ok ok...I thought they were missing! Better like this then!

So....time to pettester??

 

[daver2]

>>> So....time to pettester??

Yep!

Remove the NOP generator.

Remove the EDIT ROM from UE8 and insert the PETTESTER ROM into UE8.

Dave

 

[Desperado]

Ok but for this 8296D, which is the correct pettester version?

 

[daver2]

What do you mean?

Dave