English Amiga Board


Go Back   English Amiga Board > Support > support.Hardware

 
 
Thread Tools
Old 31 July 2015, 01:46   #1
amigaosx
Registered User

 
Join Date: Aug 2014
Location: Montevideo
Posts: 21
Amiga 500 keeps rebooting, then works fine

Hi,
the problem is that the Amiga 500 keeps rebooting until it works fine.
It shows the light grey, white screen, the keyboard leds blinks, all this for a couple of minutes more or less, until it does a final reboot and everything works fine. It responds to the CTRL+A+A meanwhile is booting.
Video here: [ Show youtube player ]

It does this only the first time I power it up. It's like it needs to get 'warm'.

Things I've tried:
- re seating all chips
- cleaning motherboard with contact cleaning
- removing all chips, cleaning sockets
- removing 512k ram expansion (trapdoor)
- trying a different disk drive

Today I've replaced a couple of burned resistors (R401 and R408), a user told me that they were just for controlling voltage to the joy ports.
But the problem is still there.

Could this be the capacitors?
I have this Amiga since 1990, it's a rev 6A-A03
amigaosx is offline  
Old 31 July 2015, 09:01   #2
Toni Wilen
WinUAE developer
 
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 43
Posts: 21,889
Works normally after warming up period usually is caused by bad capacitor(s), including PSU caps.

Do you have another PSU? Did you try swapping CIA chips (CIA-A to CIA-B and vice versa)?. Try also without display cable.

This kind of reset loop can be caused by stuck CIA timer (or timer that looks like it is stuck due to for example lack of proper clock signal) or boot code detecting non-existing genlock.
Toni Wilen is online now  
Old 31 July 2015, 17:52   #3
amigaosx
Registered User

 
Join Date: Aug 2014
Location: Montevideo
Posts: 21
thanks Toni,

I don't have another PSU to test it. I'll swap the CIA chips as you say.
I forgot to mention that the last reboot before the A500 starts to work normally gives a guru meditation error, then you click the mouse and everything works fine.

thanks again
amigaosx is offline  
Old 05 August 2015, 17:56   #4
amigaosx
Registered User

 
Join Date: Aug 2014
Location: Montevideo
Posts: 21
Today I've swapped the CIA chips and the problem persist.
Try booting without the display cable and same thing.

I don't have another PSU, so what I did is disconnect the PSU from the Amiga and power it on to warm up, then connect it, same problem.
I don't know if that's a way to test if the PSU is faulty or not.

So I think the only thing to try is to replace the motherboard caps?
amigaosx 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
Amiga 500 green screen & constant rebooting Snowwie support.Hardware 9 04 March 2015 23:01
A1200 no video on Composite or RGB, works fine with Scando Akira support.Hardware 1 14 January 2014 22:05
A1200 works fine, but led keeps blinking Riempie support.Hardware 1 04 January 2014 17:30
WHDLoad on PC works fine but not on real Amiga DC33 support.Apps 17 04 September 2011 21:57
Cdtv remote: works fine but A doesn't work jolly11 support.Hardware 5 02 December 2009 07:24

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 16:14.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2018, vBulletin Solutions Inc.
Page generated in 0.05890 seconds with 13 queries