Apple Computers & iMac - Repair, Mod, and Upgrade!

[samsonlonghair]

Edit: By the way, does anyone know how I can plug a line into the headphone jack without turning off the external speakers? I'm experimenting different ways to use this machine as a jukebox in my audio setup.

Far as I have seen, the system turns off the internal speakers at a low level (some say hardware, some say low level OS). The much simpler route to "fixing" this is to use a USB audio device instead (can be had for a few bucks). At the very least, that will let you toggle things without needing to unplug them, since having one won't disable the internal speakers.

Thanks for responding, isiola. I appreciate your insight, and a link to a cheap adapter.

My research also indicated that an external digital audio device was the way to go. If I get a digital output, I can use the audio midi setup utility to create a multi-output device to do what I want. I was looking into firewire devices first, but I didn't see exactly what I was looking for in that category, and nothing I saw was priced reasonably. I looked into USB 1.1 devices next. I saw the Creative Extigy USB sound card, which would give me a nice array of inputs and outputs, but it's been off the market for years now so supply of good confirmed working units is a little bit short. There are a couple on the 'bay, but not a lot.

That simple USB dongle DAC you linked for me looks like a nice, clean setup. I might just need to get myself one of those. Thanks, isiola.

The other solution I've tried messing with before is Soundflower (I think the older edition will work on PowerPC, the reborn one is a no go). That will basically let you create a virtual audio device for output, which you can then manipulate settings for...though it may not help if the internal speakers disappear on a system level. Haven't it for this purpose, I was trying to use it to give a volume control for HDMI audio out, since OS X completely disables that and a user really wanted it.

I had never even heard of this one. Looks interesting, but I don't see much documentation. I'm not sure if this would do what I want or not. It's interesting though.

[isiolia]

I had never even heard of this one. Looks interesting, but I don't see much documentation. I'm not sure if this would do what I want or not. It's interesting though.

Yeah, it didn't quite work for me when I tried it either (OS version being used was too new at the time). I think it's usually used more for piping sound output from one application to input in another, stuff like that. There are how-tos around the internet for accomplishing other things. It was just something I thought of that might be able to do it, even if you'd have to grab an old version for PowerPC support.

Personally, I'd go the DAC route - tons of options there, and it suits the jukebox usage more I think.


Unrelated, I have the iMac I've been working on fixed up... but I'm planning to do a CPU swap, and the replacement is shipping from China. So, kinda waiting on that to post progress/pics.

[CRTGAMER]

By the way, does anyone know how I can plug a line into the headphone jack without turning off the external speakers? I'm experimenting different ways to use this machine as a jukebox in my audio setup.

The earphone jack cutting off on board audio also an issue on HDTVs that kill the TV speakers when connecting a sound bar. There should be an option of keeping the the TV or in your case the computer speakers enabled for connecting external speakers. See my link below; should do the trick allowing an external amp setup. Perhaps supplement your Apple with the Harmon Kardon iSub Soundsticks?

Audio Out Mod - viewtopic.php?p=1005514#p1005514

[isiolia]

Hm, I haven't usually seen that as a forced thing on newer TVs. When it's intended for headphones like in your guide that may be different, but for a modern sound bar I'd tend to expect a digital connection (most TVs have optical out, HDMI ARC, or even Bluetooth to facilitate that sort of thing).


iMac I'm working on seems to have a GPU heatsink problem. Not too uncommon, apparently - fractures in the heat pipes allow the liquid/vapor to escape, killing the ability of it to keep the GPU cool. I hadn't seen it so much as ramp the fan up before, but after installing 10.11 and trying some Youtube playback, it went on full blast and wouldn't cool down, even at idle. So I guess I'll have to look into replacing that as well.

[samsonlonghair]

iMac I'm working on seems to have a GPU heatsink problem. Not too uncommon, apparently - fractures in the heat pipes allow the liquid/vapor to escape, killing the ability of it to keep the GPU cool. I hadn't seen it so much as ramp the fan up before, but after installing 10.11 and trying some Youtube playback, it went on full blast and wouldn't cool down, even at idle. So I guess I'll have to look into replacing that as well.

It's true that some iMacs in that generation have a GPU heatsink problem. That is a valid possibility, but I have to ask this: Are you 100% sure that the heatsink is the cause of your problem? I don't mean to condescend to you; I just like to troubleshoot these problems by ruling out simpler possibilities first.

In any Macintosh, the simplest reason why the fans might run at full blast is that there's no communication with one of the thermal sensors. There is a thermal sensor on the hard drive, another connected to the LCD, an ambient temp sensor, one next to the processor, and one coming out of the heatsink on the GPU. There may be other thermal sensors in your iMac as well; Lookup the teardown of your iMac online (link) to see where all the thermal sensors are located. If OSX does not get a reading from one or more thermal sensors, the fans will run at full blast.

I experienced this first hand with my Early Intel iMac. When I bought the iMac, the HDD had already been pulled for data security (and the thermal sensor with it) so OSX ran my fans at full blast. Even after I installed a cooler SSD with no moving parts, OSX still cranked my fans to maximum to prevent my drive from overheating. I'm using an application called SMC fan control to crank those fans back down to a moderate speed.

Try installing a temperature monitoring application, and see if you're getting a reading from all your thermal sensors. If you're not getting a reading from one of the sensors, then you know the problem. On the other hand, if you do get a reading, then you get to see more information about how your iMac is heating. You can use this info to your advantage to aid diagnosis and avoid overheating.

There are many temperature sensor monitoring applications. I'm a "keep it simple" kind of guy, so I like to use the application that's simply called "Temperature Monitor" by bresink software for old versions of OSX. It shows the temperature of every sensor on my machine.
http://www.bresink.com/osx/LegacyProducts.html

I assume you have already opened up you iMac, right? I further assume you have cleaned out the years of dust that accumulated inside to block airflow, right? If not, take care of that.

If all else fails, I guess you could replace the heat pipes and/or the heatsink. I have no idea how you would source replacement heat pipes. Heck, I guess I could consider bending solid 8-guage copper wire into place; I know that's not the same thing as a real heat pipe, but sometimes you gotta get creative and improvise.

[isiolia]

Try installing a temperature monitoring application, and see if you're getting a reading from all your thermal sensors. If you're not getting a reading from one of the sensors, then you know the problem. On the other hand, if you do get a reading, then you get to see more information about how your iMac is heating. You can use this info to your advantage to aid diagnosis and avoid overheating.

That's what I did. I was already trying to in order to compare results with the CPU swap. The GPU was showing temperatures beyond thermal shutdown levels for most CPUs (I think it was in the 140-150 degrees Celsius range). So, it doesn't seem like it's blowing the fan due to no reading, but due to overheating. There was also degraded performance in Safari after just a few minutes. I hadn't seen issues, or anything but whisper-quiet operation from it prior to that, but I hadn't really done anything that would have engaged the GPU either (and even this was just, presumably, hardware video decoding). Suffice to say that I turned the machine off rather than risk damage, especially given what the original LCD looked like - it would not surprise me if this was the reason for that, though I don't know if it'd explain the rust.

I saw the symptoms described on an iFixit (I think?) post with the cause being the heatsink, so I just wound up ordering one on eBay for $10 shipped. Admittedly, I haven't yet taken the thing -entirely- apart yet (waiting on the CPU since I don't want to have to do it repeatedly), so it might be slightly hasty. However, the CPU heatsink is cooled by the same fan/vents, and that was fine.
So, I'm not 100% sure, but I think it's pretty likely.

[samsonlonghair]

Try installing a temperature monitoring application, and see if you're getting a reading from all your thermal sensors. If you're not getting a reading from one of the sensors, then you know the problem. On the other hand, if you do get a reading, then you get to see more information about how your iMac is heating. You can use this info to your advantage to aid diagnosis and avoid overheating.

That's what I did. I was already trying to in order to compare results with the CPU swap. The GPU was showing temperatures beyond thermal shutdown levels for most CPUs (I think it was in the 140-150 degrees Celsius range). So, it doesn't seem like it's blowing the fan due to no reading, but due to overheating. There was also degraded performance in Safari after just a few minutes. I hadn't seen issues, or anything but whisper-quiet operation from it prior to that, but I hadn't really done anything that would have engaged the GPU either (and even this was just, presumably, hardware video decoding). Suffice to say that I turned the machine off rather than risk damage, especially given what the original LCD looked like - it would not surprise me if this was the reason for that, though I don't know if it'd explain the rust.

I saw the symptoms described on an iFixit (I think?) post with the cause being the heatsink, so I just wound up ordering one on eBay for $10 shipped. Admittedly, I haven't yet taken the thing -entirely- apart yet (waiting on the CPU since I don't want to have to do it repeatedly), so it might be slightly hasty. However, the CPU heatsink is cooled by the same fan/vents, and that was fine.
So, I'm not 100% sure, but I think it's pretty likely.

Makes sense to me; your logic is solid.

I never knew you could get a replacement on eBay so cheap. Does it come with the copper heat pipes already formed into the correct shape? If so, I'm impressed.

[isiolia]

I never knew you could get a replacement on eBay so cheap. Does it come with the copper heat pipes already formed into the correct shape? If so, I'm impressed.

Working pull is what it says. It was a little on the low end for one, but they seem to be common enough as used parts (CPU ones are even cheaper). At least for now.

Similar to why I was looking at a CPU swap, since it was $15 shipped to get a C2D T9300 (half of what one would need to get it running Sierra, even though I don't plan to do that).

[samsonlonghair]

I never knew you could get a replacement on eBay so cheap. Does it come with the copper heat pipes already formed into the correct shape? If so, I'm impressed.

Working pull is what it says. It was a little on the low end for one, but they seem to be common enough as used parts (CPU ones are even cheaper). At least for now.

Similar to why I was looking at a CPU swap, since it was $15 shipped to get a C2D T9300 (half of what one would need to get it running Sierra, even though I don't plan to do that).

Cool!

Sierra on a Core2Duo? I dunno, man That might be stretching it. I think you are wise not to run Sierra. El Capitan is a better match for that hardware.

Sierra wouldn't recognize your GPU hardware at all. Come to think of it, that's one way around an overheating GPU! Just use embedded Intel HD graphics with no hardware acceleration whatsoever. That sounds like a pleasant user experience, doncha think?

[isiolia]

Sierra on a Core2Duo? I dunno, man That might be stretching it. I think you are wise not to run Sierra. El Capitan is a better match for that hardware.

Sierra wouldn't recognize your GPU hardware at all. Come to think of it, that's one way around an overheating GPU! Just use embedded Intel HD graphics with no hardware acceleration whatsoever. That sounds like a pleasant user experience, doncha think?

Intel HD graphics weren't until the i-series - for Core2s it was still GMA and integrated into the chipset (or not, in this case). It'd actually be a nice option, to be able to pull the GPU and just use that, but alas, not in this.

Most 2009 iMacs still used Core 2 series CPUs, and can run Sierra well enough. My reluctance (besides just not really having a need to) is that, in my observation, Sierra doesn't run very well on 4GB of RAM, even on much newer hardware. That's all this machine has in it (or officially supports). It can apparently be pushed to 6GB, but the cost for the 4GB DIMM to do that isn't appealing. Meanwhile, El Capitan still works fairly well on that amount.

Plus there's the whole needing to get a patched installer and all that. I haven't seen people saying that the GPU wouldn't work, but support for the wifi card isn't there (that's the other half of the upgrade, in my mind).

Still, same conclusion that 10.11 is just a better fit.