Amiga 500 PAL/NTSC switch question..

[zektor]

Well, I am pretty proud of myself as I bit the bullet and installed a PAL/NTSC switch on my Amiga 500. Not a big deal for someone used to modding their Amiga, but this was the first real modification I have ever done to the system and it works perfectly.

I did have a question regarding it however. I was previously turning off the system before moving the switch and then turning back on, but I realized that if I simply move the switch while it is on and do a CTRL-A-A (reset) I can reset to PAL or NTSC on the fly without cycling power. My question is tho, is it safe to switch the switch while the A500 is on?

[rkauer]

 Not recommended at all! You can fry the Agnus.

[zektor]

That is what I figured. Well, I am never doing that again Luckily I didn't fry anything. Thanks for the reply!

[Zac67]

Not recommended at all! You can fry the Agnus.

That's bull - have been doing this for years with a 500 and a 3000. It's just a TTL input, so why should anything break?
(Hardswitching is the only way to switch a A2024 Hedley monitor from 1024x1024 to 1024x800. ;-))

[brianb]

rkauer wrote:
 Not recommended at all! You can fry the Agnus.

What do you base this on?   I have this setup as well, and see no way you could "fry" the chip.  It's just changing the TTL state.  If anything the chip may not like the logic state changing while running, but it would not "fry".  You may just have eradicate behavior until a hard reboot. But even that issue is a REMOTE chance, as it appears to just check the logic state on start up.

[Zac67]

Well, a hardware-switched-to-PAL-after-boot NTSC machine doesn't behave any differently than a software-switched-to NTSC-after-boot PAL machine.

(Yes, it does: the wall clock runs fast on the latter A500 - that's why big box machines use the PSU's tick for the CIA timer.)

You can happily throw the switch dozens of times while the machine is running without any problems.

[zektor]

You know, I had more thought about this myself after I had posted. Seems to me the only time the machine detects for PAL/NTSC is at boot/reboot. Flipping the switch while on does nothing in the effect of "frying" anything. Well, thanks everyone for the input.