ROM Problem

[Mark Cohen]

Hi,

I am using the PAL-1 I just assembled and I am now testing it.

The expansion rom partially works but only when the switch is set to lower memory.

On lower memory I seem to see the menu for the higher memory, basic etc. but the programs only show starting when I run them.

Where should I begin to debug?

Thanks

[Jim McClanahan]

I'd start by looking for solder bridges on the connector to the bus. Sounds like maybe some address lines aren't getting set like they should when the processor is running.

Thanks,

Jim W4JBM

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[Mark Cohen]

There are no solder bridges.

I ordered a new ram expansion just in case.

[GN L]

If there are no solder bridges, you can check that all the pins of the ROM chip are shining and making good contact with the ZIF socket.

Also, ensure that the three jumpers on the ROM board are correctly set.

Liu

[GN L]

Based on the pictures, it seems your expansion RAM jumper isn't set correctly. The jumper on the right side of the PAL-1 logo on the PAL-1 PCB needs to be open.

> On Jul 7, 2024, at 1:10 PM, Mark Cohen <markc...@gmail.com> wrote:
>
>

[Mark Cohen]

All of that looks good.

[Mark Cohen]

Plugged in directly the ROM seems to work. So I think the issue is motherboard or ram.

See pictures.

[Mark Cohen]

It works with the motherboard. So that only leaves ram which I know is suspect and I ordered a replacement. The ram is one I had laying around as it was previously replaced but I had hoped it would work. Will see when new one arrives. Or it could be something when I tell the Pal-1 to use the expansion ram.

[GN Liu]

The order of the posts seems to be messed up. My reply above should be after Mark's three posts.

[Mark Cohen]

Well it seems to have healed. Got this today.

I really did nothing different. Perhaps I plugged the cards into different slots.

Or maybe it is intermittent.

Will see what happens.

TY!