English Amiga Board


Go Back   English Amiga Board > Support > support.Hardware

 
 
Thread Tools
Old 27 May 2006, 21:36   #1
whitebird
Registered User
 
Join Date: May 2006
Location: France
Age: 44
Posts: 197
problem with an amiga 1200 motherboard

Hi all,

I bought a second hand A1200 board but it seems not to be working.

There are no peripherals connected to the board (no keyboard, no floppy drive, nothing just power supply)

When I turn on the power, a black screen appears and is displayed during a few seconds then the system seems to reboot and I see again this black screen and so on and so on...

So I decided to check the roms. I made a little electronics circuit with a 16F84 PIC. This circuit reads the ROMS and sends the data to a PC. When memory dump ended, I had a 512K rom file on my PC which I tested with Winuae, but all is working well... So ROMS are OK.

What is the reason of this bug?? Is it because there is no floppy drive connected?? Is it mandatory to have this device attached to the board during boot up??

Thank you in helping me.
whitebird is offline  
Old 27 May 2006, 22:15   #2
Smiley
Amiga-less!
Smiley's Avatar
 
Join Date: Feb 2005
Location: UK
Posts: 1,350
No its not mandatory to have a floppy drive attached
Smiley is offline  
Old 27 May 2006, 22:46   #3
whitebird
Registered User
 
Join Date: May 2006
Location: France
Age: 44
Posts: 197
OK so it is just a little monger to boot?
whitebird is offline  
Old 27 May 2006, 22:47   #4
whitebird
Registered User
 
Join Date: May 2006
Location: France
Age: 44
Posts: 197
sorry a little longer
whitebird is offline  
Old 27 May 2006, 23:41   #5
Parsec
Registered User
Parsec's Avatar
 
Join Date: Feb 2003
Location: Lancashire
Age: 44
Posts: 431
Can you test it with a different power supply?
Parsec is offline  
Old 27 May 2006, 23:50   #6
RetroMan
Registered User
RetroMan's Avatar
 
Join Date: Aug 2001
Location: Germany
Age: 46
Posts: 3,704
Without IDE HD the A1200 can take up to 30 seconds for booting up ...
RetroMan is offline  
Old 28 May 2006, 00:07   #7
whitebird
Registered User
 
Join Date: May 2006
Location: France
Age: 44
Posts: 197
Parsec, I have no other power supply but I know the one I have is not faulty because it works with other amigas.

I really don't know what is wrong with this board. The fact that it reboots periodically looks like a software related problem. Perhaps rams are bad or there is a cpu heating up problem (bad CPU). But the problem can be custom chip related.

Where can I find information about custom chips chronograms and in general repair tips for the amiga 1200?
whitebird is offline  
Old 28 May 2006, 00:42   #8
DDNI
Targ Explorer

DDNI's Avatar
 
Join Date: Mar 2006
Location: Northern Ireland
Age: 45
Posts: 5,195
Send a message via ICQ to DDNI Send a message via MSN to DDNI
You didnt say whether there was an expansion card in the trapdoor slot.
If there is try the A1200 without it.
DDNI is offline  
Old 28 May 2006, 12:21   #9
whitebird
Registered User
 
Join Date: May 2006
Location: France
Age: 44
Posts: 197
No, there isn't any expansion board attached.
whitebird is offline  
Old 28 May 2006, 20:35   #10
Overdoc
Commodore Collector
 
Join Date: Aug 2001
Location: Austria
Age: 48
Posts: 835
Hard to say, but the fact that it stays black and reeboots is typical for a bad CIA or a trapdoor expansion problem, at least on A-500s.
Anyway it would be interesting to see how the power led is doing (blinking ?!), and if the diskdrive would be reacting in some way ?
Also, have you tried holding down both mouse buttons when switching it on to get into the startup-mode ?
Overdoc is offline  
Old 29 May 2006, 19:19   #11
whitebird
Registered User
 
Join Date: May 2006
Location: France
Age: 44
Posts: 197
What you are saying is interesting Overdoc. I'll try to connect some LED's and try to see if I can enter the startup mode. I'll also try to connect a floppy drive to see how it behaves

Thanx
whitebird is offline  
Old 29 May 2006, 21:57   #12
whitebird
Registered User
 
Join Date: May 2006
Location: France
Age: 44
Posts: 197
I had a more carefull look to the board and noticed one PCB track is broken! It's the track between Alice's pin n°4 and Lisa's pin n°64 (on the DRD bus) I don't know what's the purpose of this bus but it probably helps the system in working correctly when it's connected :-) I didn't repair it yet, but I'll try it very soon

Someone knows what the DRD(31-0) bus is??
whitebird is offline  
Old 01 June 2006, 22:05   #13
whitebird
Registered User
 
Join Date: May 2006
Location: France
Age: 44
Posts: 197
I finally solved the problem which was due to the broken track as described in my previous message.
whitebird is offline  
Old 01 June 2006, 22:19   #14
keropi
.
 
Join Date: Oct 2004
Location: Ioannina/Greece
Posts: 5,040
very nice!!!! congrats!
keropi is offline  
Old 02 June 2006, 19:00   #15
whitebird
Registered User
 
Join Date: May 2006
Location: France
Age: 44
Posts: 197
Thanks Keropi
whitebird is offline  
Old 02 June 2006, 19:24   #16
Parsec
Registered User
Parsec's Avatar
 
Join Date: Feb 2003
Location: Lancashire
Age: 44
Posts: 431
Quote:
Originally Posted by whitebird
I finally solved the problem which was due to the broken track as described in my previous message.
Well done - you should offer a repair service with skills like that! Might make u a few quid too
Parsec is offline  
Old 03 June 2006, 02:57   #17
amethyst
Registered User
amethyst's Avatar
 
Join Date: Jan 2006
Location: England
Posts: 38
Quote:
Originally Posted by whitebird
Someone knows what the DRD(31-0) bus is??
It's the DRAM Data bus lines
amethyst is offline  
Old 04 June 2006, 12:06   #18
whitebird
Registered User
 
Join Date: May 2006
Location: France
Age: 44
Posts: 197
Quote:
Well done - you should offer a repair service with skills like that! Might make u a few quid too
In fact the big challenge was to repair the track directly on the PCB rather than adding a long wire between Alice and Lisa. So I had to insert a very short wire in an area were the tracks are very close one of the other.


Quote:
It's the DRAM Data bus lines
Thanks
whitebird is offline  
 


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
wtb: amiga 1200 motherboard CU_AMiGA MarketPlace 0 05 May 2009 14:14
WTB: Amiga 1200 motherboard Gavilan MarketPlace 2 21 February 2009 19:10
wtd amiga 1200 motherboard webhead MarketPlace 8 15 August 2007 13:08
For sale: One Amiga 1200 motherboard. baggy2 MarketPlace 9 11 July 2005 05:07
Price of an amiga 1200 motherboard? baggy2 support.Hardware 1 29 June 2005 22:29

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +2. The time now is 23:07.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Page generated in 0.08724 seconds with 13 queries