Generous soul needed!.

[deckart]

Hi all.
Just received a 1st Gen Imac g5 17".PSU is dead due to blown fuse.Part is this:http://gb.mouser.com/ProductDetail/L...P7/gXKoBvNe7k=
The lead time for this is 12 weeks!,searched all my sites in UK and they are the same,does anyone have a spare er,floating around?,if so I will put you on my Xmas card and favourite person forever list!.
Happy Xmas,
J-P.

[i4004]

Re: Generous soul needed!.

come on, you can't find 4A 250V fuse in some other form and attach it there is some way?

oh yeah, fuses usually blow for a reason, so get more than one, as there are chances the new one will blow too if you didn't remove the real cause of its failure....

[smeezekitty]

Re: Generous soul needed!.

In almost any case you can replace the fuse with a higher one if it is a reasonable amount (Eg 5 or 6 amp) because, if it could blow a low amp fuse 90% chance of blowing a slightly higher one.

[deckart]

Re: Generous soul needed!.

Lol,I've thought of fusewire but it wouldn't look neat,know what I mean.The space is 8 x 4mm and this little puppy is rubbing shoulders with all it's mates.So been there etc,T-shirt wearing at the moment,but nothing will fit in this space.All similar fuses are on same lead time or I have to bulk buy 1000's of the bleeders.
So still stuck.
Lummy.

[Toasty]

Imac G5 17" PSU fuse blown

Fuses don't -usually- blow for no reason. ESPECIALLY in these units. You have larger problems I'm afraid.

Is this a glass fuse? If so, did the wire just open or is there a black mark on the glass?

Brand & Model of PSU please. Apple P/N too. Photos top and bottom if you would, will help this voyeur.

Possibilities:
-MOV(s) shorted due to voltage surge
-mains cap or diode failed
-main inductor shorted
-bridge rectifier shorted
-main switcher(s) shorted
-5vsb or 24vsb primary circuit failure

Look forward to your responses.

Toast

[i4004]

Re: Generous soul needed!.

>So been there etc

ok, you've been there, but have you been slightly above, ie are you telling me you can't put two wires and and a fuse and put them somewhere in there?

at least untill you get them at mouser, as i think there'll be some more work there, fuse aside...

[deckart]

Re: Generous soul needed!.

Arghhhh,I don't know,just got it today,opened up Imac no LEDS lit up,no blown caps,though it looks like a refurbished LB,due to the existence of larger caps which in my experience,they are usually all the same size.
Chucked in my spare PSU,part no:614-0333 and started up ,installed 10.6,ran CPU Test 2,ASD,all fine.Turned to original PSU.No output voltages on jumped leads.Opened up PSU,no blown caps,then found blown fuse.
Conclussion,power surge could have caused this on non UPS/surge protected system,or original owner tried to power up system on non isolated enviroment.
In which case the PSU might have saved itself further damage,but can't test without this fuse!.
Very frustrating.

[ratdude747]

Re: Generous soul needed!.

have they ever considered a circuit breaker for a power supply?

[Toasty]

Re: Generous soul needed!.

>>but can't test without this fuse!.<<
??? You want to make sure the new fuse blows too ???

>>have they ever considered a circuit breaker for a power supply?<<
Yes, some used to have them, even fuse holders where you could replace them. But, idiots taped circuit breakers down so they would hold -or- put 25A fuses in where 6A were supposed to be, or wrapped the blown ones with aluminum foil.

Consequently they burned down their houses and then successfully sued the <<insert any consumer appliance type maker here>> because they didn't take the proper precautions to prevent that from happening.

From that came fusible links that prevent any possibility of replacement by the normal idiot, and soldered in fuses, and warnings about "No Serviceable Parts Inside", and "Service by Qualified Service Personnel Only", and Security Torx screws, and one-way screws, and hermetically sealed cases, and airplane owners manuals that CLEARLY STATE "DO NOT ATTEMPT TO OPERATE THIS AIRCRAFT UNDER THE INFLUENCE OF DRUGS OR WHILE INTOXICATED"!!! Ask Piper about that one....

+ = NO FLYING !!!

[i4004]

Re: Generous soul needed!.

>but can't test without this fuse

oh yes you can, just find a fuse of same electrical charactersitics and connect it where old fuse was.
it doesn't have to be that exact fuse.
so fuse is not preventing you.

put a fuse of same rating, connect it on the PCB somehow and turn it on. if it blows again then you'll have some more work and waiting just for that nice fuse is useless.

can we move on now?
or will you just repeat once again it has to be this exact fuse, because "it looks pretty"?
hehe...

[deckart]

Re: Generous soul needed!.

It's tighter than a Gnats chaff in there.Tighter than tight day in Tight Land.So as it looked so pretty in there and really nothing else would do,because it really is pretty,I half inched the same type and rating from an Intel PSU I had propping open a well thumbed and loved picture book of my prettiest fuses and popped it in there.
Gentleman,the rest is academic.

[deckart]

Re: Generous soul needed!.

Photo.

[Toasty]

Re: Generous soul needed!.

WOW. Glad none of my questions were answered....

[deckart]

Re: Generous soul needed!.

Sorry Toasty,I couldn't answer your questions because I had no idea of the history of this Imac,just got it from Ebay in the UK.As said nothing lit up,caps looked good on the LB,so figured it was PSU.On taking it out smears were evident on the body of the Imac.On this Acbel the fuse is shrouded in a plastic coat ,so damage is hidden,just DMM tested,no continuity.
Just wander how/why it blew,like I said,power surge,anyway took a few minutes to replace and so far temps/fans(using Istat) and CPU levels are fine.

[hardwareguy]

Re: Generous soul needed!.

You got lucky...most PSUs that have a blown fuse blow the replacement as well.

It was probably a surge....the MOV shorts the surge and keeps it from frying the PSU...this overloads the mains line and the fuse blows.

[Toasty]

Re: Generous soul needed!.

The MOV may be damaged and not protect again.

>>the fuse is shrouded in a plastic coat ,so damage is hidden<<
It's called a knife.

>>Brand & Model of PSU please. Apple P/N too. Photos top and bottom if you would<<
Umm...?
"couldn't answer your questions because I had no idea of the history of this Imac"

[deckart]

Re: Generous soul needed!.

Running CPU Test V0.2 at the moment,If anything is going to blow the two MOVS this will.10 hours so far,so good.

[Toasty]

Re: Generous soul needed!.



MOV's have -nothing- to do with the CPU or loading of the supply.

[c_hegge]

Re: Generous soul needed!.

You got lucky...most PSUs that have a blown fuse blow the replacement as well.

I've found exactly the same thing. I replaced a fuse in an el-cheapo "PT" branded PSU. Plugged it in and it went BANG, gave off sparks and smoke and blew the replacment fuse.

[deckart]

Re: Generous soul needed!.

In hindsight Toasty,you are right.Although it seems to be running fine at the moment I am going to replace the PSU with my known untampered good one.I have not got the resources to properly test the movs.Better safe than sorry I say.