Problem With PSU Flex Cable iMac Late 2013

[jasongoldworthy]

hi guys as the title says

I upgraded my storage in the iMac with the blade drive and the HDD.

and now im getting fans on full belt. it boots.

and says you need to reset the SMC when I run Macs fan control.

so I didn't glue the display back on at the time.

I removed the screen and noticed that the cable is in but its very easy to come out of the connectors.

do these cables go bad ??

I reseted the cable and booted the iMac and it was normal again the SMC was detected but after rebooting its back to the same issue.

p.s I can't turn it on with the power button either it turns on automatic.

ive tried a pram reset with no go.

but I think that cable must have an issue of some sort.

thanks for any help.

 

[Lifeisabeach]

It's possible you damaged the cable when you reinserted it. But the reason the fans spin up at full speed is that starting with the 2010 models, the HDDs in these iMacs come with custom firmware and if you replace the HDD with a 3rd party, the fans ramp up. Using Macs Fan Control is one way to manage this, but a BETTER way is to use OWC's thermal sensor upgrade.

OWC In-line Digital Thermal Sensor for 27-inch iMacs

OWC's in-line solution is the only hardware digital thermal sensor on the market allowing a third-party SATA drive to be installed in your iMac.

eshop.macsales.com

 

[jasongoldworthy]

It's possible you damaged the cable when you reinserted it. But the reason the fans spin up at full speed is that starting with the 2010 models, the HDDs in these iMacs come with custom firmware and if you replace the HDD with a 3rd party, the fans ramp up. Using Macs Fan Control is one way to manage this, but a BETTER way is to use OWC's thermal sensor upgrade.

OWC In-line Digital Thermal Sensor for 27-inch iMacs

OWC's in-line solution is the only hardware digital thermal sensor on the market allowing a third-party SATA drive to be installed in your iMac.

eshop.macsales.com

hi thanks for the reply I thought that may be the case.

so after I rebooted the machine I run the apple hardware test

and have found 2 error's

ill attach an image here

I replaced the original drive and same results fan is on full speed.

I tried Macs fan control but its saying to reset the SMC and so far that's not worked.

have I damaged the logic board somehow ?

 

[Lifeisabeach]

The fact that it's saying there may be a problem with the camera also is concerning. I'm not familiar with your model iMac, but if I had to guess, the problem may be a damaged cable or two, or possibly a loose one. It's not hard to break one in these... I snapped one particularly fragile cable myself the first time I did an HDD swap in a 2010 iMac long ago.

I was just reading over iFixIt's HDD replacement guide, and I noticed a couple very specific cautions about removing the display panel and taking care to stop at a certain point or you risk damaging the camera. So that's a potential point of failure in that regard. Have you tried using the camera?

 

[jasongoldworthy]

well I did test the camera and its working so unless the SMC is the problem its saying about the camera im not sure.

im wishing now I didnt change the drive lol.

as it was working perfectly before that.

and to be honest as I have opened up several times the one im currently using I can't image I would have damaged something.

I did check the cable again that connects the logic board to the psu. and there is continuity both ends of it.

so id say that's good ??

one more thing if that's not connected it still turns on automatically. and fans running full speed.

I think ive fudged the logic board somehow ??

 

[jasongoldworthy]

The fact that it's saying there may be a problem with the camera also is concerning. I'm not familiar with your model iMac, but if I had to guess, the problem may be a damaged cable or two, or possibly a loose one. It's not hard to break one in these... I snapped one particularly fragile cable myself the first time I did an HDD swap in a 2010 iMac long ago.

I was just reading over iFixIt's HDD replacement guide, and I noticed a couple very specific cautions about removing the display panel and taking care to stop at a certain point or you risk damaging the camera. So that's a potential point of failure in that regard. Have you tried using the camera?

hi again I think ive found the culprit ive knocked off the most smallest of resistors.

I dunno how well this will show up on the photo ive attached

but any ideas if I can get one to fit this small area ??

 

[Bill Gates Jr.]

Do you know the resistor value?
Perhaps an Apple repair shop can take the resistor off of an old circuit board (used for parts) if no surface mounted resistors are available. I've never tried to solder or unsolder Surface mounted components myself but understand it is difficult. I grew up on vacuum tubes, then transistors, then Intergrated circuits. Got out of the rear side went into teaching then auditing then retirement before encountering Surface mounted components like resistors, capacitors, etc.
It may be possible to jury rig a 1/4 watt or 1/8 watt resistor by soldering the resistor and bending the leads as flat as can be against the board, probably would need to slip insulation over the leads to prevent shorting anything out.
Because soldering surface mounted components are difficult to replace most repair, I believe most repair is board replacement.

 

[AndrewDun]

Dealing with these minute things looks more daunting than it really is. The first requirement is someone else's reading glasses or find a pick-your-own type which you can wear over your own, to allow you to focus at about 6". Can you find another logic board to look at to read the resistance, or judge from the circuitry what it might have been for. If just to protect an IC input from excess current it would be fairly non-critical — say 1k to even 10K. But if part of a voltage divider, then important to get it about right. Find any fairly modern scrap pcb and look for a suitable resistor. (Are you sure it was a resistor? caps. and diodes can have the same footprint.) Heat the scrap board from underneath over an electric ring or with a hot air blower, and nudge a nearby component to see if it is loosened (solder melted). If so nudge your replacement part free and pick it off with tweezers. (It will leap out of the tweezers if it gets half a chance.) Place the part in position, preferably apply a little flux (violinist's rosin dissolved in alcohol works fine). If you feel brave you could heat the board locally from underneath until the solder runs, but it is unnecessarily risky. With an ordinary small soldering iron, and old-fashioned tin-lead solder, and a steady hand, it is not too difficult. Best to clean up afterwards with more alcohol and a toothbrush. Yes, a wire-ended component can certainly be used, but is, of course, more likely to be knocked off accidentally. And it might be worth practising the repair on a scrap board first. Good luck, Andrew.

 

[jasongoldworthy]

hi guys thanks to both of your replies.

sorry im slow replying.

as for knowing the value I have looked up the schematic and board view file I have both.

and found that its resistor R5120 but if I have read it correctly its a 10K resistor.

I do have an identical logic board with the component in place.

but I think the trace is gone on the working one.

the other board I have has a boot issue where it just freezes on boot.

 

[AndrewDun]

Can you see both ends of the "gone" trace? If so, and with good glasses, you might be able to bend some 5a fuse wire or similar along its route and solder both ends to the remains of the trace, or to the solder at the next components at each end. "Mechanical" repairs (soldering things etc.) seem so much more straightforward than tracking down freezing on boot type problems. I gave up on a 2007 iMac which suddenly developed a black screen, fans full on problem. I didn't know where to start having exhausted all the re-setting type solutions.
P.S. How did you come by the schematic?

 

[jasongoldworthy]

I googled the logic board to find the schematic and board view files.

as for the end of the trace one is there still and I found the other goes to a via and I can get continuity there.

so I could probably source a resistor of the same one from my faulty logic board as that's intact.


and trust me that's why I replaced the logic board originally because I couldn't find the issue of it freezing but without an OS it would flash the question mark folder as if it was behaving normal.

it wouldn't even boot to recovery without freezing so I assume there is some sort of issue somewhere lol.

 

[AndrewDun]

I think you were lucky to find that schematic. I have never found one for any Mac I have been involved with, and I have thought myself lucky even to find Apple's service manual. I think that they withdrew them years ago, but some still hang about. As for schematics, well!
I still have my black screen iMac, thinking that one day I will learn what the problem is, so I would not cannibalise it willingly. But I find so many defunct or abandoned appliances everywhere that any common component is always to hand on a scrap board. There must be people who understand logic boards in the way that lesser folk understand old amplifiers etc, but they do not surface readily when I do google searches for these obscure-seeming board faults.
If the "gone" trace is very long, there is nothing to stop you just running a length of insulated wire between its ends, and perhaps glueing it to the board here and there.
Hope it all works. It is very satisfying to get something back into working order.

 

[Bill Gates Jr.]

i/20 Watt resistor,10K SMC (Surface Mounted Component) is very low wattage resistor. One thing to consider is what caused the resistor to blow. You may replace it and find that the new one also gets fried. The switch in the schematic is to put a ground, temporarily, below the 10K resistor. Maybe creating some kind of reset. If that switch is bad and keeps the ground on the resistor, that could cause it to fry the resistor. Measure from the bottom of the resistor trace to ground to see if a permanent ground is on that trace. Switch would then probably be bad. Is there a way to check the switch? Pete

 

[jasongoldworthy]

i/20 Watt resistor,10K SMC (Surface Mounted Component) is very low wattage resistor. One thing to consider is what caused the resistor to blow. You may replace it and find that the new one also gets fried. The switch in the schematic is to put a ground, temporarily, below the 10K resistor. Maybe creating some kind of reset. If that switch is bad and keeps the ground on the resistor, that could cause it to fry the resistor. Measure from the bottom of the resistor trace to ground to see if a permanent ground is on that trace. Switch would then probably be bad. Is there a way to check the switch? Pete

hi pete

it didn't blow I somehow accidentally knocked it off the logic board.

(no idea how)

and to be honest with you ive tried to solder one from a bad logic board on and didn't get anywhere.

so ive just ordered a replacement logic board with a better GPU and CPU.

thanks for all your advice

Jason

 

[jasongoldworthy]

hi pete

it didn't blow I somehow accidentally knocked it off the logic board.

(no idea how)

and to be honest with you ive tried to solder one from a bad logic board on and didn't get anywhere.

so ive just ordered a replacement logic board with a better GPU and CPU.

thanks for all your advice

Jason

well guys the replacement logic board arrived and now im worse off than I was before.

the seller confirmed the item working perfectly.

but it in fact is dead

I get the 1st led on the logic board that lights up when I press the power button the hard drive spins and that's it no fan spin no second light no chime nothing....


I think I am doomed with this second machine.

 

[AndrewDun]

When you say you tried to solder one from a bad logic board on and didn't get anywhere, do you mean that the soldering was too difficult, or the soldering went satisfactorily but the board is still faulty?

 

[jasongoldworthy]

When you say you tried to solder one from a bad logic board on and didn't get anywhere, do you mean that the soldering was too difficult, or the soldering went satisfactorily but the board is still faulty?

I couldn’t seem to get it to take maybe I should use hot hair ?
From a hot hair station

 

[AndrewDun]

Cleanliness is everything. Can you go over the pads on which the resistor was soldered perhaps scraping lightly with the end of a knife (rounded, not pointed), and when clean solder or copper is revealed, smear a little flux on the pads, similarly make sure your soldering iron tip is clean. You can wipe it when hot on a damp rag, and it should look shiny. A little flux there as well, and a touch of solder on the tip. Now, without much delay, touch the tip of the soldering iron on each pad. Each pad should now have a shiny rounded low mound of solder. (I would stick to old fashioned tin-lead solder — it works much better.) Now do the same on the resistor (if it has not yet leapt into the distance) or its wire-ended replacement if you cannot find another 10k surface-mount one.
If you have a hot air station you could now use it. Smear the solder pads with flux, place the resistor in position and heat it until it sits down comfortably. Or, just with a soldering iron, hold the resistor in place, just touch each end with the (still clean and shiny) soldering iron and watch the solder melt and unite. (Remember the close-up glasses.)
Flux: flux core solder works quite well if everything is clean and you can work quite fast, but it is a great help to have some extra flux available. Ideally non corrosive electrical type, but you can even use plumber's if you take car to clean up thoroughly afterwards. I have a lump of old tallow, tins of old Fluxite, violinist's rosin, zinc chloride, and a tiny bottle of something intended for BGA rework. Anything will do.

 

[jasongoldworthy]

Cleanliness is everything. Can you go over the pads on which the resistor was soldered perhaps scraping lightly with the end of a knife (rounded, not pointed), and when clean solder or copper is revealed, smear a little flux on the pads, similarly make sure your soldering iron tip is clean. You can wipe it when hot on a damp rag, and it should look shiny. A little flux there as well, and a touch of solder on the tip. Now, without much delay, touch the tip of the soldering iron on each pad. Each pad should now have a shiny rounded low mound of solder. (I would stick to old fashioned tin-lead solder — it works much better.) Now do the same on the resistor (if it has not yet leapt into the distance) or its wire-ended replacement if you cannot find another 10k surface-mount one.
If you have a hot air station you could now use it. Smear the solder pads with flux, place the resistor in position and heat it until it sits down comfortably. Or, just with a soldering iron, hold the resistor in place, just touch each end with the (still clean and shiny) soldering iron and watch the solder melt and unite. (Remember the close-up glasses.)
Flux: flux core solder works quite well if everything is clean and you can work quite fast, but it is a great help to have some extra flux available. Ideally non corrosive electrical type, but you can even use plumber's if you take car to clean up thoroughly afterwards. I have a lump of old tallow, tins of old Fluxite, violinist's rosin, zinc chloride, and a tiny bottle of something intended for BGA rework. Anything will do.

thanks for the advice ill give that a go I have nothing to lose in doing so (other than my sanity) and I think that's gone already lol...