exxos's Atari, Amiga & retro forum

pakman wrote: 28 Jan 2019 19:42 With the PAK assembled into the MegaST, of cause..

Ok, that will tskr me a bit longer as it's not in a socket. Will reply with result when done.

Ok, that's the 16v8 U3 removed and jumpers on j6 and j5, the pak doesn't boot.

I tried with and without 68000 connected too

Next, on the PAK:
- Remove both TagRAMs
- Remove both 74F541
Jumper settings:
J1on (68030 internal MMU disabled)
J2 on (68030 internal cache disabled)
J3 off (FPU now disabled)
J4 on
J5 on
J6 on
J7 1-2
J8 2-3
J9 1-2
J10 1-2
J11 1-2
This is the absolute minimum configuration.. try to boot.

Still no boot and /halt and reset are still high as well if that helps.

Ok, then the remaining possibilities are:
1. Problem with the GALs
2. Problem with the ROMs
3. Some wiring problem (short or open)
Do you have spare GALs and ROMs to rule out hardware defects? I will send you the latest JEDECs for both ( but not before Thursday, since I am not at home right now). Let us continue by then..
By the way, which TOS do you prefer: UK or US?

I have some ATF22 equivalents or maybe 1 or 2 Gals. I think I have some more eproms but can always erase those and reprogram, so no problem there.

I would prefer UK tos given the choice.

Thank you for your help so far.

One or two more tests regarding the wiring..
Please get a multimeter and measure:
- Is there a connection from U5 pin20 to pin 11 of the 68000 socket on the top side of the PAK?
- Is there a connection from U5 pin20 to the 68000 pin 11 on the bottom side of the PAK?

pakman wrote: 29 Jan 2019 19:18 One or two more tests regarding the wiring..
Please get a multimeter and measure:
- Is there a connection from U5 pin20 to pin 11 of the 68000 socket on the top side of the PAK?
- Is there a connection from U5 pin20 to the 68000 pin 11 on the bottom side of the PAK?

There is a connection from the bottom of the board on pin 11 on the CPU pins to U5 pin 20.
Nothing from the CPU socket on top of the board when tried with U5 pin 20.

Is GAL P3 required if it's just the PAK without PuPla?

Atarian Computing wrote: 01 Feb 2019 14:11 Is GAL P3 required if it's just the PAK without PuPla?

There is no relationship between GAL P3 and PuPla at all.

P3 is required if you have a 68000 on your PAK.
Then you can switch with J5 between 68030 and 68000.
Make sure J6 is open, when P3 is installed.

With no 68000 installed, you can totally omit P3.
Make sure J6 is set (closed) when P3 is not installed.