Is this what a bad rom looks like? (2732)

[jms2]

I've been trying to diagnose a faulty TI99/4a for a while, and have come to the conclusion that the rom may be bad - the machine is giving all the right signals across the PCB, but just isn't doing any of the boot sequence. So I decided to desolder the roms and dump them. They are TMS4732 roms, which are 24-pin devices with the same pinout as a 2532 EPROM. My Willem programmer won't read 2532s, but the difference to a 2732 is quite small (only 3 pins) so I made up an adaptor.

Dumping the roms shows that one of them contains mostly just "&10", with some regions of "&14". The other one is entirely "&17".

Now, obviously this is not right. But I don't have any good 2532 roms with which to test my setup, so it could be that my adaptor has a fault, or I haven't set up the Willem properly (although I think both aspects are OK). So it would be useful to know anyone's experience of:

- If a rom were bad, would it look like this?
- Is it plausible that both roms could be bad?

[jms2]

I have adjusted the adaptor to better mimic the circuit in the TI99, in terms of the chip enables. I still get exactly the same result though, which is leading me to think the roms really are bad.

Next step is to create an adaptor which makes a 2764 fit in the TI.