A2000...possible PSU issue?

[Fingerlickin_B]

Yet again, I have a problem...

I'd test the PSU, but my multimeter is giving bad readings on devices & components of known values (needs a new battery, not really an option at 2am!).

The A2000 seems to be displaying symptoms of a bad PSU, but maybe I'm wrong?

This has all happened since installing a Picasso II (& only started f*cking up today):
a: Native screens have horisontal fuzz/lines,
b: Picasso display relay (that switches between PII & native) sometimes doesn't switch over when promted by software as normal (resulting in native WB & Intuition freakout),
c: Buddha doesn't always seem to work at powering on & end up with no HDD noise, straight to Kickstart requester,
d: If some non-crucial devices (like ZIP drive & extra fan) are disconnected, some (but not all) of the native mode fuzz goes away.

Sounds like a bad PSU...or doesn't it?

PZ.

[Fingerlickin_B]

Also get Lurbi's problem as seen here:

http://eab.abime.net/showthread.php?t=43084

But only sometimes & with 2mb chip + 6mb fast, this should not happen.

PZ.

[Zetr0]

@Fingerz

when dealing with intermitent problems across a range of essentially unrelated components (i.e. adapter cards) then it can only be the thing they share the most - POWER

In this case I would also say as you have - that the PSU is not got enough guts to it anymore and is struggling.

its a shame you dont live close I could chuck you a 300watt ATX - alas it would take a while from here and get a bit wet in the process.... not to mention sea water isn't good for most ferrous metals =(

[Fingerlickin_B]

Thanks for the confirmation Z-man...a spare ATX PSU will go under the knife tomorrow!

PZ.

[Fingerlickin_B]

So I just painstakingly wired up a known working ATX unit & jumped J300 on the 2-3 pins as per instructions here:
http://www.ianstedman.co.uk/Amiga/am...SU_to_an_A2000

No good...displays a black screen only!

Any ideas?

PZ.

[orange]

there is Tick generator on aminet that works on +5V.
I think thats better than J300.
triple check all voltages. is power LED on?

[Loedown]

Originally Posted by Fingerlickin_B

So I just painstakingly wired up a known working ATX unit & jumped J300 on the 2-3 pins as per instructions here:
http://www.ianstedman.co.uk/Amiga/am...SU_to_an_A2000

No good...displays a black screen only!

Any ideas?

PZ.

I have two ideas;

1. You cocked up one of the wires or left it disconnected.

2. The power supply isn't being loaded up enough to start.


I have a Thermaltake ATX supply in mine which runs it just fine, 400 or 450W from memory.

[Fingerlickin_B]

Originally Posted by Loedown

1. You cocked up one of the wires or left it disconnected.

I triple-checked it as I went, so everything should be connected correctly.

2. The power supply isn't being loaded up enough to start.

Please elaborate?
I just grounded the switching wire via a switch (this same PSU worked that way in my A600T.

Cheers for the help

PZ.

[orange]

you don't have to worry about load if voltages are OK. obviously, the PSU has started.
I'd check +5V_USER once more. and that jumper (might be oxidated after long time).
I hope you are removed all cards, etc..

[Loedown]

Some modern power supplies fail to start if they don't have enough load on the 3.3V rail.

http://www.pcguide.com/ref/power/sup...Loading-c.html

Read on the side of your ATX PSU what it requires as current draw to start.

[Fingerlickin_B]

No need, I just fired up my multimeter with the help of a transformer (battery dead as noted above).

Only getting 10 volts on the 12 volt line, so that must be it.

To be sure the multimeter wasn't lying to me, I tested another PSU & sure enough, this one gave me 12.6 volts.

Funny...it worked fine for an A600 (as already mentioned).

Ok, so maybe if I have time after work tomorrow, I'll wire up the one that just tested as good.

Thanks heaps guys & sorry for wasting your time!

PZ.

[Zetr0]

Originally Posted by Fingerlickin_B

Thanks heaps guys & sorry for wasting your time!

PZ.

bah! dont be silly, we all start somewhere - and no one person can ever know it all.....


well... maybe doomy....

[Fingerlickin_B]

Doomy! What ever happened to him?

Hey Zetro, I suppose the dud PSU probably powered the A600 ok & not the A2000, due to the latter requiring more juice?

This might be a good time to ask if people post some pics of their ATX units installed in A2000s...I'd like to see

PZ.

[Fingerlickin_B]

@Orange: I could only find it in French...

PZ.

[Loedown]

Originally Posted by Fingerlickin_B

Doomy! What ever happened to him?

Hey Zetro, I suppose the dud PSU probably powered the A600 ok & not the A2000, due to the latter requiring more juice?

This might be a good time to ask if people post some pics of their ATX units installed in A2000s...I'd like to see

PZ.

Ask and thou shalt receive

http://eab.abime.net/showthread.php?t=51982

[Fingerlickin_B]

Whoots!!!!

[Zetr0]

@Fingerz

on the A600/A500 and A1200 the -12 is mainly used for the sound generation - so its unlikely that low 10.6v reading will stop the machine from booting - Although I would expect the sound to be really crap on the output - and any external (or internal) device that need a -12v, would just not work.

Within the A2000 however the -12v (-12V_USR) is also fed to the the 8bit, ISA and Zorro2 Ports - so its quite likely with any adapter cards requiring the -12V will hang the boot

[Fingerlickin_B]

All cards fitted when I tried it, so that must be the case

Might have to buy an ATX socket & make a cable. That way I don't have to solder every time a PSU dies!

*EDIT* - Just purchased the parts to make said cable

Thanks again fellas!

PZ.

[orange]

here is mine:
http://www.amiga.org/gallery/index.php?n=2081

(actually, I sold it recently, but I did the mod)

[Fingerlickin_B]

Cool!