Can JS ROM be used with QL manufactured for US market

[lowrybt]

Hello,

Any reason why a JS ROM (Euro version) cannot be used in a QL that was manufactured for the US market?

Thnks, Tom

[tofro]

The US version of the QL has a different timebase (1/60s instead of 1/50s) than the European versions. Most of the short timing (Microdrives, network) in the OL is being done using tight CPU loops, those shouldn't be affected.

The polling interrupt that interrupts the user programs would however be based on that smaller timebase. There could be functions that would possibly be affected by that (maybe the clock runs faster and keyboard auto-repeat might be different).

But generally, the QL should start up and run.

On the other hand, I think Minerva used to run well in U.S. QLs - And there never was any specific version of that for the US QL.

Regards,
Tobias

[RWAP]

I have a set of JSU ROMs if you need them (I think).

I think the main issue is the characters - the UDGs for D-Day and War In the East were different dependent on whether a JS or JSU ROM was being used - but this was due to the difference in TV frequency I believe (and a US QL has a little switch under the modulator to switch between the output - also from memory).

[Dave]

The US version of the QL has a different timebase (1/60s instead of 1/50s) than the European versions.

It is 1/60s if you choose TV. It is still 1/50s if you choose monitor with a JSU ROM.

[lowrybt]

So I pulled the JSU ROMs and replaced them with the JS+TK2 ROM kit that José Leandro sells with the Qubide clone. The result: no joy. The machine entered an unstable cyclical boot\reboot mode with the screen displaying various off-nominal graphics. Sometimes the familiar pre-boot garbage graphics showed up on some portion of the screen. But in the end, the machine got stuck rebooting every 3-4 seconds.

I alternately subtracted components and peripherals to get to a stable condition. The only way to get the machine stable was to replace the JSU ROMs or to use the Minerva ROM that I have. I do have some of the UK\Euro JS ROMs. Going to try those next.