Hi,
My imac g5 has just died i think ;( Bought it 2 yrs. ago with a faulty PSU and worked fine after repairing it!
Status right now, all of a sudden:
- no chime anymore
- freezes with white screen
- seeing some artefacts at the place of the Apple logo.
When hitting the Imac a little bit, i see some pink artefacts. I tried to reflow the nVidia fx5200 ujyt322GPU, but still it isn't working.
Does anyone recognise this problem? All three leds lighten up, butt the fact i don't hear the chime is something i can't explain?...
koektrommel
Member
Last Activity: 02-10-2017, 07:21 PM
Joined: 05-13-2010
Location:
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Imac g5 2006, no chime, some artifacts, freezing
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Re: Imac G5 20"' black screen only
Because when i put the hairdryer there and getting them really hot, the chime came back and it started directly. I heated the different capacitors several times separately and only when i heated those 120uF, the chime and startup came.
I've checked the great banks, removed all the right 2 rows of capacitors from the bank: all good: >1800uF and esr-values of 0.02 ohm each. None of them was bad! I made a mistake by telling earlyer that i measures values of 0.12ohm or so.
Replaced the 1000uF chemi-con KZJ caps,... -
Re: Imac G5 20"' black screen only
I''m not convinced yet
I thought i found the capacitors that gave the problem. Heating that place would give the chime and startup back. So i thougt, let's remove those and check them to see if they're really the ones that are giving the problems:
The answer: nope I measured all the 120Uf/16V Chemicon KY and these were also OK! Capacitance of 116 and 121, ESR-value of 0,19 which is also OK. ( I had some 100uf here, but they're new and having an ESR which is 0,25 so i didnt replace them.
...Leave a comment:
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Re: Imac G5 20"' black screen only
You were right. I forgot that these were low esr caps. For general purpose capacitor the esr is quite right according to my opinion. But most of the time i see really swollen or bad caps with complete gone capacity and extreme high ESR-values.
I tried the hairdryer on it and with hot capacitors it started how it should be
... this thing is lying here for more than eight months. Tried to change the batterie, measured the capacitors but i couldnt find out which one. I think i made a mistake somewhere.
Didnt...Leave a comment:
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Re: Imac G5 20"' black screen only
Hi Toasty,
I measured the ESR from each capacitor. I thought the ESR was plusminus 0.10 ohm or so. The capacity was also ok as far as i could measure. None of them was bulging. I've repaired many settopboxes and know from that experience that the chance of a bad cap is big but to my opinion these are all ok, although they could have a lower esr offcourse. Otherwise i would have measured bigger ESR-values .
I got two lights, which indicates a problem with the logicboard communication. I simply won't start up anymore...Last edited by koektrommel; 12-04-2010, 02:08 AM.Leave a comment:
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Re: Imac G5 20"' black screen only
I forgot to ask the question whether it could have something to do with RAM-memory? Or a defective RAM-slot?Leave a comment:
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Imac G5 20"' black screen only :(
Hi,
I have problem with an 20" Imac G5 i bought recently. It's a model from i quess 2005.
The problem is i think somewhere on the logicboard, since the PSU is 100%. I checked that by simple putting in a good working PSU.
Symptons, in folowing of happening:
- first, it bootet up normally. Chime, screen, all oke and lasting for hours.
- When you shut it down and start up again it sometimes worked well, sometimes it won't start up at all or the screen stayed black (but.. Chime!) The fan obviously blowing fast.
- Now, i... -
Re: SMD diode with Red-orange-blue
Thanks for the replies. I really appreciate it!
I'll try to check the voltages if that's possible. I found out that according to the colours it should be 6.3V or 3.6VLeave a comment:
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Re: SMD diode with Red-orange-blue
You can see the diode on the picture at the link. It's marked as ZD6 on the psu, so i think it's indeed an Zenerdiode.
But, what's strange is that on a similar PSU, there's on position ZD6 a diode with only a yellow stipe on.
I'm thinking this red-orange-blue is not good anymore: when using the digital multimeter in diode testing mode, it's measuring 45 and 45 out of circuit. Is it correct, that that diode is not good anymore?
The diode at the same position on the working PSU gave different...Leave a comment:
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SMD diode with Red-orange-blue
Or blue-orange-red.
Anyone any idea? I need to replace one, but i really have no idea what knd off diode it is?
It's probably a switching diode, but i need it's specifications so i can find one to replace
It's ZD6, just below and to the right of the circle.
See this picture, which is made by another member who had the same problems!
[url]https://www.badcaps.net/forum/attachment.php?attachmentid=13706[/url]https://Or blue-orange-red.<br /> <... idea what kndLast edited by koektrommel; 05-22-2010, 06:01 PM. -
Re: iMac G5 17" ALS - Troubleshoot - bad PSU?
Well, i can use some help.
Im looking for a certain diode on the PSU, labeled as ZD6.
I have one on my failed PSU, where transistor Q1 was blown and i think it took diode ZD1 with it. This diode gives weird readings: unsoldered it measured 045 und 045. On another, well working psu, the diode on the same place gave a totally different reading. It acted as a normal diode, showing reading nearby 7-800 and 1.
Can anyone tell me what kind of diode this is, and how and where to order one?Leave a comment:
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Re: Another sick iMac G5 PSU
And a bump upwards!
I have a PSU with a Q1 blown also. I've found a (zener)diode with weird readings;
It's the same as the diode directly under the circled position ; diode ZD6
See an earlier posted picture from another user: [url]https://www.badcaps.net/forum/attachment.php?attachmentid=13706[/url]
It's readings out of circuit, using a DMM in diode-measurement: 045 and 045. Both directions the same? It's allready replaced once. On another identical PSU which didnt show ant resoldering marks, there's another...Leave a comment:
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