A500 Boot Problem

scrappysphinx · 06 March 2008, 01:40

Hi Guys, i picked up 2 boxed 500 Machines, both upgraded to 1mb with trapdoor ram, 3 'tank' mouses, 2 joypads, 2 Modulators, original workbench disks v1.3 and v2.05 and a 500 PSU from my local admag paper tonight.
Advert said all in working condition for £15.
Having watched a few standard A500's on ebay fetching around £15-£20 i thought this would be a decent deal.
However upon arrival they guy said that the PSU had blown while testing during the day but the amigas were fine.
I eventually bought the lot for £10.

I got home and tested my 1200 PSU on the 1st 500 and it booted up fine stating workbench 1.3 and the familiar hand/disk logo.
I then tried the 500 PSU on the 1200 and that too booted up fine.
So now i have a working A1200 & a working A500 and two working PSU's.
I then turned my attention to the 2nd 500. I tried plugging in both PSU's but i got nothing on screen and no power/floppy LED.
I thought it might be a loose chip inside so i opened up both the working and non working 500's to look for any obvious differences.
I pulled out, cleaned and reseated all chips on the dead 500 and plugged in the PSU.
I now have power getting the board but the power LED on the amiga just flickers on and off very fast.
When connecting a scart i get a white flash on screen.
I removed all chips from working board and seated into dead board but still get the fast power LED flashing and white flash on screen.
I then took all the chips i had removed from the dead board and placed them into the working board.
Working board still booted up fine so i assume all chips are ok.
I have swapped the ram upgrades over incase it was a dead upgrade preventing boot but still getting same flashes.
On the dead 500 if i get my ear close to the mainboard i can hear a ticking somwhere around the denise or 68000 chip, anyone have ideas?
Could this be a simple fix or is it looking like a dead board?

Many Thanks

Mike

scrappysphinx · 07 March 2008, 10:15

update:

I continued to play around with the motherboard and now instead of a white flash i get a sort of green/blue flash.
The ticking is still there though.
Any ideas?

Thanks

Mike

CRAZG · 07 March 2008, 10:31

Try resoldering any capacitors in the area of the "ticking".

06 March 2008, 01:40	#1
scrappysphinx Registered User Join Date: Jan 2008 Location: Nottingham Age: 39 Posts: 480	A500 Boot Problem Hi Guys, i picked up 2 boxed 500 Machines, both upgraded to 1mb with trapdoor ram, 3 'tank' mouses, 2 joypads, 2 Modulators, original workbench disks v1.3 and v2.05 and a 500 PSU from my local admag paper tonight. Advert said all in working condition for £15. Having watched a few standard A500's on ebay fetching around £15-£20 i thought this would be a decent deal. However upon arrival they guy said that the PSU had blown while testing during the day but the amigas were fine. I eventually bought the lot for £10. I got home and tested my 1200 PSU on the 1st 500 and it booted up fine stating workbench 1.3 and the familiar hand/disk logo. I then tried the 500 PSU on the 1200 and that too booted up fine. So now i have a working A1200 & a working A500 and two working PSU's. I then turned my attention to the 2nd 500. I tried plugging in both PSU's but i got nothing on screen and no power/floppy LED. I thought it might be a loose chip inside so i opened up both the working and non working 500's to look for any obvious differences. I pulled out, cleaned and reseated all chips on the dead 500 and plugged in the PSU. I now have power getting the board but the power LED on the amiga just flickers on and off very fast. When connecting a scart i get a white flash on screen. I removed all chips from working board and seated into dead board but still get the fast power LED flashing and white flash on screen. I then took all the chips i had removed from the dead board and placed them into the working board. Working board still booted up fine so i assume all chips are ok. I have swapped the ram upgrades over incase it was a dead upgrade preventing boot but still getting same flashes. On the dead 500 if i get my ear close to the mainboard i can hear a ticking somwhere around the denise or 68000 chip, anyone have ideas? Could this be a simple fix or is it looking like a dead board? Many Thanks Mike

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07 March 2008, 10:15	#2
scrappysphinx Registered User Join Date: Jan 2008 Location: Nottingham Age: 39 Posts: 480	update: I continued to play around with the motherboard and now instead of a white flash i get a sort of green/blue flash. The ticking is still there though. Any ideas? Thanks Mike

07 March 2008, 10:31	#3
CRAZG 2 heads are more than 1 Join Date: May 2007 Location: Tauranga / New Zealand Posts: 38	Try resoldering any capacitors in the area of the "ticking".

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