Commodore PET CBM 4016 ASSY 8032080 RIFA burn and more

[DrAlis]

UC5/1 is flat LOW

 

[DrAlis]

Generally, I get no more chirps, also the bright green center dot does not show up anymore.

 

[daver2]

>>> CRTC pin 39 has action pin 40 is flat as per images

You can't have the oscilloscope at 500 ns/div to detect a signal of 50 Hz or 60 Hz on pin 40 (VDRIVE). It is waaaaaay too fast...

Dave

 

[DrAlis]

I thought your machine was a 40 column machine?

Is J1 or J2 installed?

Dave

I have never seen it running. Case says 4016. Garbled screen looked 40 when it worked briefly sporadically. I wanted to take an osci image and now the sine clock is gone... sine clock is back.

 

[DrAlis]

UE5 Pin 6

 

[DrAlis]

CRTC Pin 40 with coarser time res

 

[DrAlis]

But as we have no chirp and crtc logic should we not stop worrying for video sig until we have chirp?

 

[daver2]

UE6 pin 5 is correct at 16 MHz.

What about UD2 pin 10 now?

Is it 16 MHz or 8 MHz? It should be 8 MHz for 40 columns with J1 installed.

Do you have a horizontal line on the CRT in that mode?

Dave

 

[DrAlis]

jumpers

 

[DrAlis]

UD2 Pin 10 and 11 are disconnected from the board. crt screen black as night.

 

[DrAlis]

Image for the flying pins of ud2

 

[daver2]

They are not all of the jumpers. In fact, you have missed jumpers J1 and J2 (which I specifically asked for).

Either J1 or J2 should be installed.

I am getting lost again...

Dave

 

[DrAlis]

More jumpers. Sorry did not know where J1 is

 

[daver2]

Right, so J1 is installed but UD2 pins 10 and 11 have been disconnected.

OK, still no problem.

That means UC1/11, UC1/3, UB2/11 and UA2/7 should be 8 MHz.

Dave

 

[DrAlis]

still more jumpers they are hiding everywhere

its 40

 

[DrAlis]

Right, so J1 is installed but UD2 pins 10 and 11 have been disconnected.

OK, still no problem.

That means UC1/11, UC1/3, UB2/11 and UA2/7 should be 8 MHz.

Dave

UC1/11, UC1/3, UB2/11 and UA2/7 confirmed all 8 mhz

 

[daver2]

>>> Its 40.

It is only 40 if ALL of the links are set for 40 columns as per the assembly diagram https://www.zimmers.net/anonftp/pub/cbm/schematics/computers/pet/univ/8032080-7.gif.

The assembly diagram also shows where all of the components (including links) are...

Dave

 

[daver2]

UC1/11, UC1/3, UB2/11 and UA2/7 confirmed all 8 mhz

OK.

So, go around UC1 pins:



Dave

 

[DrAlis]

1 high
2 low
3 clock
4 high
5 low

 

[daver2]

Pin 2 being LOW is bad news.

So, same on these pins...


Dave