As I mentioned I use such a cheap old DDR voltage regulator to reduce the voltage to 220 volt to keep the PET and other old equipment cooler.
It's a Feutron 1223.
Very cool tip. I also have an adjustable thoroid somewhere. I'll have a look.
As I mentioned I use such a cheap old DDR voltage regulator to reduce the voltage to 220 volt to keep the PET and other old equipment cooler.
It's a Feutron 1223.
Very cool tip. I also have an adjustable thoroid somewhere. I'll have a look.
This is a PET 2001 board. There is no 7905 regulator.........killed all dynamic RAM
DOH sure, static rams on the early pets, i always forget
This is a PET 2001 board. There is no 7905 regulator.........killed all dynamic RAM
DOH sure, static rams on the early pets, i always forget
Geht mir ja auch oft so. Bei den vielen Boardvarianten verliert man schnell mal den Überblick. Ich habe auch vorher noch mal in den Schaltplan geschaut, um sicher zu sein.
sockets.. grr
sockets.. grr
grr indeed. i am loosing my mind over this old crap.
I repaired more than one PET by just replacing all sockets.
I've inspected and measured every single pin. It's not the sockets...
Shall I replace all ceramic capacitors as well?
( this feels really hopeless )
I'd switch the socket to a turn pin socket first. Maybe it just was (abiding to Murphy's law) working temporarily during testing. The video clearly indicates the socket. And those white ones are nororious for it.
I'd switch the socket to a turn pin socket first. Maybe it just was (abiding to Murphy's law) working temporarily during testing. The video clearly indicates the socket. And those white ones are nororious for it.
okay, I'll swap them all
It wasn't the socket.
I've replaced the char ROM socket first, then burned a new ROM. According to the schematics, the VIA [A5] CA2 line is controlling the Business/Graphic modes, that line was floating hence the change in characters on the screen.
The garbage screen is pretty consistent, there are no fluctuations in content between resets or cold starts.
Maybe the PET wants a hug?
Tried that as well just in case. It needs something else...
I'm sure, it deserves one, like every one of them does.
The same screen content every time? That's strange.
The same screen content every time? That's strange.
yepp. every single time.
Did you try a NOP adapter to check the adress an /CS lines?
This is, what I would do next.
Did you try a NOP adapter to check the adress an /CS lines?
This is, what I would do next.
I did not tried that yet. I've only tested the CPU off board.
I could drive the address and select lines with a microcontroller to see if the traces are intact. ( Is this what you meant, but with a nop adapter right? )
A µC ... OK, in german we would say 'Wer keine Arbeit hat, der macht sich welche'... unless you already have some test device ready to go.
A simple NOP adapter an a oscilloscope helps testing the adress lines and their buffers and the /CS lines to work and have correct TTL levels.
A µC ... OK, in german we would say 'Wer keine Arbeit hat, der macht sich welche'... unless you already have some test device ready to go.
A simple NOP adapter an a oscilloscope helps testing the adress lines and their buffers and the /CS lines to work and have correct TTL levels.
well. Either I build a NOP adapter or use a bunch of probe wires... but today I don't really feel like it.
Unless you have something like this: http://blog.tynemouthsoftware.…6/07/pet-diagnostics.html
which unfortunately seems to be no longer available , a NOP Adapter should be the most efficient next step.
Unless you have something like this: http://blog.tynemouthsoftware.…6/07/pet-diagnostics.html
which unfortunately seems so be no longer available , a NOP Adapter should be the most efficient next step.
whoa. this would be amazing, even for an hour.
Oh, wow. A FPGA board and an Raspberry Pi for debugging a PET. That's a lot of hardware.
As I mentioned before I prefer the PET RAM/ROM-Board.
It has no debug options, but it can replace RAM and ROM. So you can easily find RAM and ROM errors. And you can keep inside the PET for 32KB of RAM and switching between different ROM versions.
Alles anzeigenOh, wow. A FPGA board and an Raspberry Pi for debugging a PET. That's a lot of hardware.
As I mentioned before I prefer the PET RAM/ROM-Board.
It has no debug options, but it can replace RAM and ROM. So you can easily find RAM and ROM errors. And you can keep inside the PET for 32KB of RAM and switching between different ROM versions.
This is also interesting. Do you know a German source, so I can order one?
As I mentioned before I prefer the PET RAM/ROM-Board
Yes, I find it very helpful, too.
nilseuropa : If you are interested, I may send you a unpopulated PCB.
As I mentioned before I prefer the PET RAM/ROM-Board
Yes, I find it very helpful, too.
nilseuropa : If you are interested, I may send you a unpopulated PCB.
Toast_r that would be amazing! Thanks
Just PM me your address.
Here is the link to the information again:
http://vic-20.de/x1541/hardware/petram.html
Can you program the GAL? Maybe Toast_r can send you a programmed one.
I can do that too but it will cost extra shipping.
Thanks hans !