HELP! Intermittant A1200 fault

abraXXious

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Hey guys,

have a small problem. About a month ago I noticed that sometimes when I switched on my A1200 the hd would flicker (loading) for about 10 seconds and then stop displaying a blank screen. If I reset or switched the psu off then on, 9 times out of 10 it would then load fine. This started happening shortly after I installed my Prelude 1200 card.

Once loaded the machine runs perfectly. I have scanned the HD, no bad sectors etc. The HD is a compactflash card (8 Gb) btw.

Tonight I installed a slimline DVDRom into the A1200 desktop case. I am now finding that about 30% of the time the system is booting. Now resetting does not help, I must switch off then switch back on - then 1 in 3 times it will boot to WB.

Once booted it runs perfectly.

My system is:

A1200 in desktop case with 3.1 roms
Blizzard Mk IV 030 @ 50 mhz with FPU and 64 Mb ram
Prelude A1200 card
Floppy Drive
Buffered 4 device IDE interface
IDE to Compactflash adapter with 8GB Compactflash card
Slim Line (laptop) DVDRom
External RGB to S-Video adapter
PCMCIA to Compactflash adapter with 2GB Compactflash card
This is running an an A500 brick type PSU.

I am wondering if this could be a power supply problem? The problem started shortly after installing the Prelude A1200 card and got worse when I installed the DVDRom

Any help would be appreciated.
 

merlinkv

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@abraXXious

Yes, looks like a power supply failure.

You have lot of peripheals taking power from the PSU.

I have a similiar A1200D, but with one ATX modified PSU. Everything works fine, included two external floppy´s.

Cheers
 

HonestFlames

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Is the jumper on your Blizzard set to 60ns or 70ns for the RAM?

I had a minor issue with my Amiga last night. A blank screen on boot. The screen was actually the colour of the Workbench background, so it failed resonably late into the startup sequence. I'd not long added the jumper to switch my RAM to 60ns. I don't have any power issues, as I'm running of a 300W ATX.

Worth a try.
 

merlinkv

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I don´t remember exactly but the A500 PSU is 45 or 60w?

Maybe too much for Clockport HW, IDE drives (like DVD´s) & CPU board.

Best is ATX modded PSU.
 

abraXXious

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You were absolutely right Melinkv. After your post I wired up an ATX 550 watt psu to an A1200 plug - bingo, boots perfectly everytime.

Thanks for your help guys. Thread can be closed.
 

Zetr0

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I don´t remember exactly but the A500 PSU is 45 or 60w?

Maybe too much for Clockport HW, IDE drives (like DVD´s) & CPU board.

Best is ATX modded PSU.

There are infact two versions - one is 45 watts and the other 60watts.


At the momet your total load is about 40/45watts - this primarly on the +5v

On startup you would be drawing 45-50 watts.

breakdown -


1. A1200 in desktop case with 3.1 roms (12 watts)
2. Blizzard Mk IV 030 @ 50 mhz with FPU and 64 Mb ram (16watts)
3. Prelude A1200 card (5v @500ma = 2.5 watts)
4. Floppy Drive (when running = 2 watts)
5. Buffered 4 device IDE interface (100ma = 0.5 Watts)
6. IDE to Compactflash adapter with 8GB Compactflash card (300ma @ 5v = 1.5 watts)
7. Slim Line (laptop) DVDRom (6 watts)
8. External RGB to S-Video adapter (0.1 watts)
9.PCMCIA to Compactflash adapter with 2GB Compactflash card(5v@ 300 ma = 1.5 watts)

Total Wattage = 42.1 Watts ( 8.42 amps required (thats 1amp on the +12v and 5.92amps on the +5v)

Your system is drastically overloaded my friend.

The Amiga power supplies are over 15 years old, some are even 20 years old - the PSU was never designed to see 10 years of life let alone 15-20. I would hazzard an estimate that a regulatly used 18 year old power supply could only reliably pump out 60% of its rated maximium without critical votlage swinging.

In the case of the 45 watt model that would be 27 watts, in the case of the 60 watt unit that would be 36 watts

As you noted the issues happened the moment you added the Prelude sound card.... its time for a new power supply - personally I wouldn't waste money on aging kit thats only going to go pop in the next handfull of years - instead I would look at modifying an ATX power supply for your needs.

Although alternatively you could look at replacing the capacitors on the PSU - it might buy you some time - but in the case of the PSU only being a 45 watt unit - you are already at its maximum.
 

abraXXious

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Hey Zetr0,

way ahead of you - see my post just above yours. Wired up a 550watt atx PSU (pulled it apart, desoldered and removed all harnesses, soldered an A1200 lead to the apropriate voltages, connected green power on atx wire to a toggle switch and back to ground - all fits nicely in the atx case) and hey presto! 100% reliability again!

Thanks for all your help guys.
 

Zetr0

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Hey Zetr0,

way ahead of you - see my post just above yours. Wired up a 550watt atx PSU (pulled it apart, desoldered and removed all harnesses, soldered an A1200 lead to the apropriate voltages, connected green power on atx wire to a toggle switch and back to ground - all fits nicely in the atx case) and hey presto! 100% reliability again!

Thanks for all your help guys.


AWESOME!

remember - the photo-booth is there for people to "share" said hackery's =D


SO TAKE PICS!!


*ahem

please..... =)
 

merlinkv

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@abraXXious

Thanks m8.

But to be honest, time a go Zetr0 & other Amibay friends help me with my overloaded A1200D.

Congratulations! (y)
 
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