skrentny@lion.cs.wisc.edu (Jim Skrentny) (08/14/90)
A professor at the UW will be traveling to China in a month and he will be
taking his recently purchased A2500/30 with the fatter Agnus chip.
Before he leaves he would like definitive answers to the following questions:
1. Chinese power is 220V/50Hz and the power supply is rated 120V/60Hz:
An Isolated voltage converter has been purchased that will provide 120 volts
at 750 Watts (enough for the machine and monitor). Yet the line frequency
will be 50Hz.
WILL THE SWITCHING POWER SUPPLY WORK AT 50 HZ?
I have also been thinking of just replacing the power supply with a european
supply that is designed for 220V/50Hz.
WHERE CAN SUCH A SUPPLY BE PURCHASED AND HOW MUCH WILL IT COST?
I am aware that the tick signal is derived from the line frequency and this
will cause the clock to run fast. In fact I have changed the jumper such that
the tick is derived from the verticle sync.
IS THE FASTER CLOCK GOING TO PRESENT PROBLEMS?
2. Chinese monitors are PAL vs amiga's NTSC and what about RGB?
First I would appreciate a brief explanation of the amiga's video. I have
gathered that the composite output of the amiga is NTSC compatible sync, the
signal is monochrome, and it can be switched to PAL (with the fatter agnus
chip). I also presume that the RGB output also is fed off of the NTSC sync
(60 hz - vert, 15.75Khz horz).
WILL CHANGING BETWEEN NTSC/PAL AFFECT THE RGB SYNC?
There are several A2500/monitor configurations being explored:
* amiga RGB output (presummably NTSC sync) into commodore monitor that
accompanied the A2500/30.
HOW WILL THIS MONITOR POWERED BY A 50Hz LINE BE AFFECTED WHEN
SUPPLIED WITH NTSC SYNC RGB?
* amiga RGB output (switched to PAL sync) into commodore monitor
CAN THE COMMODORE MONITOR HANDLE PAL SYNC SIGNALS?
* amiga composite output (switched to PAL sync) into chinese monitor
HOW DOES ONE SWITCH THE AMIGA BETWEEN PAL AND NTSC?
I have been told that there are programs called PALBOOT and NTSCBOOT which will
switch between the two video standards.
WHERE AND HOW DO I GET THEM.
Finally HOW WILL RUNNING THE AMIGA SWITCHED TO PAL AFFECT ANY OF THE SOFTWARE
- NEGATIVELY? POSITIVELY?
I have been told that these topics were previously discussed but I have missed
them since only 2 days ago I have added this group. Please respond via email
if this has been covered.
THANKS FOR YOUR PROMPT REPLY.
--
------------
Jim Skrentny
University of Wisconsin
Computer Systems Lab
office 608-262-6606 (afternoons), home 608-251-5683
USENET: ...!{allegra,heurikon,ihnp4,seismo,ucbvax}!uwvax!skrentny
ARPA INTERNET: skrentny@cs.wisc.edudaveh@cbmvax.commodore.com (Dave Haynie) (08/14/90)
In article <11035@spool.cs.wisc.edu> skrentny@lion.cs.wisc.edu (Jim Skrentny) writes: > WILL THE SWITCHING POWER SUPPLY WORK AT 50 HZ? Yes. > WHERE CAN SUCH A SUPPLY BE PURCHASED AND HOW MUCH WILL IT COST? Some of the A2000 supplies were internally jumperable between 110 and 220, though I don't know if that's still the case. They are considered separate items on the parts list. You could certainly order a replacement 110V supply in the USA from Commodore's service department, but I doubt they stock any 220V supplies. >I am aware that the tick signal is derived from the line frequency and this >will cause the clock to run fast. Actually, the OS will adjust to either 50Hz or 60Hz. > 2. Chinese monitors are PAL vs amiga's NTSC and what about RGB? PAL vs. NTSC really tends to mean both sync and color encoding conventions. Since there is no colorburst encoding in RGB, the difference is only an issue of sync. Most, though probably not all, "NTSC" RBG monitors can be adjusted for PAL, and visa-versa. Certainly any 15kHz multiscan monitor would be happy with either. >First I would appreciate a brief explanation of the amiga's video. I have >gathered that the composite output of the amiga is NTSC compatible sync, the >signal is monochrome, and it can be switched to PAL (with the fatter agnus >chip). That's true -- the A2000 composite output is monochrome. Changing J102 on the motherboard (a PCB jumper rather than a strip-post jumper, not as easily changed as the others) will change the default mode from NTSC to PAL if you have the 1 Meg Agnus. >I also presume that the RGB output also is fed off of the NTSC sync (60 hz - >vert, 15.75Khz horz). > WILL CHANGING BETWEEN NTSC/PAL AFFECT THE RGB SYNC? Basically, the composite output is created from the RBG output. So they're always the same frequency. However, as mentioned, RBG monitors *TEND* to be relatively flexible with respect to vertical sync, and the horizontal syncs are almost the same between NTSC frequencies and PAL frequencies. > HOW WILL THIS MONITOR POWERED BY A 50Hz LINE BE AFFECTED WHEN > SUPPLIED WITH NTSC SYNC RGB? The 50Hz vs. 60Hz issue can pretty much be ignored. Video rates are based on the system's main 28MHz clock, they have nothing to do with line frequency. > * amiga RGB output (switched to PAL sync) into commodore monitor > CAN THE COMMODORE MONITOR HANDLE PAL SYNC SIGNALS? Probably. The 1070 and 1080 can; I don't know which monitor you have. > * amiga composite output (switched to PAL sync) into chinese monitor > HOW DOES ONE SWITCH THE AMIGA BETWEEN PAL AND NTSC? Right now, you need to change J102 on the A2000. If you're doing this stuff alot, you could hook a switch up there. Once you have 2.0, this switching can be done in software. And there are the hacks you mention below. >I have been told that there are programs called PALBOOT and NTSCBOOT which will >switch between the two video standards. > WHERE AND HOW DO I GET THEM. They were on the network here awhile ago, maybe someone could send you a copy. >Finally HOW WILL RUNNING THE AMIGA SWITCHED TO PAL AFFECT ANY OF THE SOFTWARE >- NEGATIVELY? POSITIVELY? Most of the time, there's not much difference. Good software will adjust. Most sloppy software works going from NTSC->PAL; sloppy PAL software may be a problem on an NTSC machine. >Jim Skrentny >University of Wisconsin >Computer Systems Lab -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy Get that coffee outta my face, put a Margarita in its place!
<LEEK@QUCDN.QueensU.CA> (08/15/90)
Be warned that the voltage regulation in some areas of China might not be very good. Watch out for that as it might damage you computer. This piece of info is at least 8 years old, so they might have fixed that up quite a bit. K. C. Lee Elec. Eng. Grad Student (Disclaimer in effect)