English Amiga Board

English Amiga Board (https://eab.abime.net/index.php)
-   Hardware pics (https://eab.abime.net/forumdisplay.php?f=77)
-   -   A1200 rev.2B motherboard: resistor in ALICE pin (https://eab.abime.net/showthread.php?t=35121)

keropi 27 February 2008 20:22

A1200 rev.2B motherboard: resistor in ALICE pin
 
I noticed this this today:

http://i125.photobucket.com/albums/p55/restqp/363.jpg

it caused some slight trouble when installing the DCE flickermagic... I have another 2B motherboard here, but it lacks this resistor... does this mean that the pictured motherboard with the resistor has the famous "timing fixes" :confused:confused:confused

laser 27 February 2008 20:49

that resistor is hack for ntsc motherboards to make boot default in pal mode instead ntsc

that hack doesn't produce timing issues

keropi 27 February 2008 21:03

what? really? so I have an NTSC mobo?
bah
will it affect me in any way?

laser 27 February 2008 21:21

Quote:

Originally Posted by keropi (Post 398524)
what? really? so I have an NTSC mobo?
bah
will it affect me in any way?

it's better for any amiga boot in pal mode by default

anyways Im not sure about that hack is 100% bug-free

it can cause some problems with scandoublers or with your particular DCE flickermagic...

bye

keropi 28 February 2008 08:45

OK, did some tests...

removed the resistor and booted. Scout gave me a PAL Agnus.
changed screenmode to NTSC, and again Scout gave me a PAL Agnus ...
using ClassicWB ADVSP btw...
so??? if it was an NTSC motherboard, removing the resistor should give me an Agnus NTSC, right?

laser 28 February 2008 09:37

Quote:

Originally Posted by keropi (Post 398579)
OK, did some tests...

removed the resistor and booted. Scout gave me a PAL Agnus.
changed screenmode to NTSC, and again Scout gave me a PAL Agnus ...
using ClassicWB ADVSP btw...
so??? if it was an NTSC motherboard, removing the resistor should give me an Agnus NTSC, right?

I don't remember if the resistor alone is the hack or another modification attend....I think that a pin of the alice chip is disconnected from the motherbpard as well to complete that hack

that hack was invented by some resellers to sell 1200' ntsc motherboards on PAL countries

btw, check what kind of video you got from composite video output



bye

keropi 28 February 2008 09:48

hmmmm
I checked the early startup menu too, PAL is pre-selected...
will try the VHS out in a while...

keropi 28 February 2008 10:09

just checked, it displays on my tv and flickers the same as my cd32/pal ...

laser 28 February 2008 11:14

Quote:

Originally Posted by keropi (Post 398594)
just checked, it displays on my tv and flickers the same as my cd32/pal ...

Ok....

which problem exactly you have with that motherboard with the resistor?
strong flicker?

keropi 28 February 2008 13:19

not really a problem, as I wrote before in caused trouble when installing the DCE flickermagic... I removed it now completelly, seems OK
will try connecting VHS to a tv-tuner and see what it gets recognised for (I have a SAA7135 based one that supports ALL formats)

keropi 28 February 2008 14:12

nice, I just checked with trusty FLY2000TV... 24.49 FPS VHS input...
I still wonder why the resistor was there in the first place... maybe I need to let it do intensive gfx stuff? an AGA demo perhaps?

Rogueraven 06 March 2008 00:38

some information here http://www.ianstedman.co.uk/Amiga/am..._mobo_fix.html

hope this helps


All times are GMT +2. The time now is 21:21.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.

Page generated in 0.04430 seconds with 11 queries