CBM 8032 - What does the startup chirp actually mean?

[dave_m]

Here is schematic of the 6502 NOP Generator. The inner 40 pin socket on the diagram is the top socket where the 6502 in installed. The outer 40 pin socket is the bottom socket connected to the board. Notice that all pins feed through to the top socket EXCEPT the data bus lines pins 26 to 33. The red lines connect to ground pin 1, while the blue line connect to VCC pin 8. For extra safety there can be a pull up resistor from the blue wires with the other end of the resistor connected to pin 8 (Vcc). This will keep the signals high without a direct connection to Vcc (+5 V).

Attachment 64922

EDIT: The outer pads are the top socket! The inner pads are the bottom socket. The IC outline is a little misleading.

[dave_m]

I'm following all your PET threads but don't seem to have the concentration any more; I tend to lose track of what's happening after around the 10th or 15th post...

Mike,
Great to 'hear' from you. This current thread is only about 80 messages and has a long way to go!

Heck, that is nothing for you. I remember one thread from many years ago where the OP was living in Japan and was repairing a 2001-8 PET. You and I were at about 200 messages before we solved it. I wish I could remember his user ID. He took nice scope photos (before the days of phone cameras) that help us a lot.

I imagine you cannot attend the Toronto PET Users Group meetings at this time. I hope the club survives the epidemic.
-Dave

[MikeS]

Mike,
Great to 'hear' from you. This current thread is only about 80 messages and has a long way to go!

Heck, that is nothing for you. I remember one thread from many years ago where the OP was living in Japan and was repairing a 2001-8 PET. You and I were at about 200 messages before we solved it. I wish I could remember his user ID. He took nice scope photos (before the days of phone cameras) that help us a lot.

I imagine you cannot attend the Toronto PET Users Group meetings at this time. I hope the club survives the epidemic.
-Dave

Hi Dave,
Thanks; I expect the club will survive, even though the meetings are virtual these days and of course the annual World of Commodore event will also have to be virtual somehow, the same as the VCFs and other conventions in these strange times.

Are you thinking of Nama with the PET in a suitcase? Haven't seen him around for quite a while.

Of course I follow all these threads and I have to hand it to you guys (and the determined folks you're helping); I can't think of one case that didn't ultimately end in a working PET if they hung in there, even if it did take 200 messages .

Strange times indeed; I hope you all stay healthy and we soon get back to some semblance of normal.

[dave_m]

Are you thinking of Nama with the PET in a suitcase? Haven't seen him around for quite a while.

Mike,
Yes, that was the fellow. I looked up the thread by searching for Nama and 2001 as I was sure it was a model 2001 PET. The thread was from 2011 and it was over 200 messages. Here is the link: http://www.vcfed.org/forum/showthrea...eeds-your-help. Too bad the links to the nice scope photos are not working.

I thought it was just the two of us helping but there were several other guys that contributed to the fix. That PET had some tricky issues. Those were the days. We fixed a lot of Commodore PETs over the years.
-Dave

[MikeP]

Hi Dave_M,

I am about to build the NOP Generator using 2 sockets. Just to clarify, I cut the data pins off the top socket and connect the data pins of the lower socket to VSS(GND) and VCC respectively?

Thanks
Mike

[dave_m]

Hi Dave_M,

I am about to build the NOP Generator using 2 sockets. Just to clarify, I cut the data pins off the top socket and connect the data pins of the lower socket to VSS(GND) and VCC respectively?

Mike,
No, The data pins on the top socket that go to the CPU are the ones tied to Vcc and ground. On the lower socket, the data lines are not connected to upper socket. See message #81 for clarification of the diagram.

[daver2]

+1

Dave

[MikeP]

OK,

It's not pretty, but here it is...
NOP1.jpg NOP2.jpg

Quality of the images is not great, I have an older iphone.

[dave_m]

Very nice job. Wiring looks good.
Wait, is that a 47 Ohm resistor? If that pull up is grounded, it would draw 100 mA and dissipate 1/2 Watt. It will give rise to Smoke!

[MikeP]

It is 47 KOhm. Very difficult to read, so I did check it with my multimeter.