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Re: Early Intel iMac - Repair it or mod it?

by CRTGAMER Tue Dec 19, 2017 7:36 pm

samsonlonghair wrote:Avert your eyes! Naked iMac!

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I believe CRT requested a look at the speakers. This doesn't look like anything special to me. I wouldn't bet on Harmon Kardon having designed this one, brother. The LCD industry has gravitated to a few de facto standards for the form factor of this connector. Let's find out if Apple is going to respect de facto standards, or use a proprietary connector. Darn it, Apple! This is not the first time that a proprietary connection has made an apple project more trouble than it needs to be.

Just in case this restoration doesn't pan out, I can re-use that wi-fi card in one of my Mac Pro towers. I don't really need it for that, since I don't currently have an internet connection at home anyway. I'm just keeping that as an option in the back of my mind.

Gaah, I hate Apple proprietary connections! Maybe just disconnect the internal monitor and use that mini port output adapted the replacement LCD? Or use one of your huge silver monitors placed in front? How do those speakers sound? Apple usually have decent speakers even though they appear to be just plain.
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Re: Early Intel iMac - Repair it or mod it?

by samsonlonghair Tue Dec 19, 2017 7:38 pm

isiolia wrote:Apple and Low End Mac say 9.2.2, not that it'd really matter a whole lot either way.

Just got a chance to follow this link you posted, isiola. This is really neat! I have never seen this archived support document before. How groovy! 8)
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Re: Early Intel iMac - Repair it or mod it?

by samsonlonghair Tue Dec 19, 2017 8:26 pm

CRTGAMER wrote:Gaah, I hate Apple proprietary connections!

Hey there, CRT! I was wondering when you would chime in. :mrgreen: Yeah, you know how I feel about Apple's proprietary connections. I'm still going to try tearing down the LG Flatron monitor and install it inside the iMac. I'm not sure how to make that happen exactly, but I'm still going to give it my darndest shot.
CRTGAMER wrote:Maybe just disconnect the internal monitor and use that mini port output adapted the replacement LCD?

That's one possible back up plan, but I'm not giving up just yet. If I quit a project every time it got hard, I'd never finish anything. You know what I mean?
CRTGAMER wrote:Or use one of your huge silver monitors placed in front?

Are you talking about those Apple Studio displays? Nah, they're already rigged up to my Mac Pro towers, and they're not that big anyway. The LCD is only 17 inches, but the bezel and the clear acrylic feet make them look larger.

Actually... I have another monitor in mind if it comes to that. I don't want to get too far ahead of myself just yet.
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Does this monitor remind you of anything?

CRTGAMER wrote:How do those speakers sound? Apple usually have decent speakers even though they appear to be just plain.

They're just OK. Nothing fancy here. I'm afraid it's a significant step down from those Harmon Kardon speakers from earlier iMac models. I think what really hurts them is that the speakers face downward. In theory, the sound waves bounce off your desk and hit your ears. It seems to me that something gets lost in translation though. I'm a "keep it simple" kind of person. I figure if you want the speakers to sound good, then point them at your head, right?
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Re: Early Intel iMac - Repair it or mod it?

by isiolia Wed Dec 20, 2017 9:24 am

samsonlonghair wrote:I figure if you want the speakers to sound good, then point them at your head, right?


To my limited knowledge of the subject, it's not that simple. Just on a basic consumer level, you do have other setups that deliberately bounce sound off of surfaces, a common example today might be sound bars, as those aim to bounce surround channel information off the walls (and ceiling for Atmos), but you have stuff like Direct Reflecting designs from Bose that did it decades ago with a mind towards reproducing a more live sound.
On a broader level, only higher frequencies tend to be especially directional to begin with, since it's harder to "contain" the larger waves generated for low frequencies. Hence baffle step compensation considerations in crossover design and speaker placement...or just why it doesn't matter as much where you put a subwoofer, I guess.

Maybe all a moot point when just talking about little full range drivers crammed into an AIO that'd fall short of some $20 computer speakers though. /shrug


Is the LVDS cable not the same on the LCD side as well? It doesn't seem like it's impossible to find third party control boards for the panels themselves, even if the connector Apple used on the motherboard side isn't standard. Hard for me to tell with the one I have...though I did pull it up from the basement, along with most of my other old computers. :lol:
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Re: Early Intel iMac - Repair it or mod it?

by samsonlonghair Wed Dec 20, 2017 10:15 am

isiolia wrote:
samsonlonghair wrote:I figure if you want the speakers to sound good, then point them at your head, right?


To my limited knowledge of the subject, it's not that simple. Just on a basic consumer level, you do have other setups that deliberately bounce sound off of surfaces, a common example today might be sound bars, as those aim to bounce surround channel information off the walls (and ceiling for Atmos), but you have stuff like Direct Reflecting designs from Bose that did it decades ago with a mind towards reproducing a more live sound.
On a broader level, only higher frequencies tend to be especially directional to begin with, since it's harder to "contain" the larger waves generated for low frequencies. Hence baffle step compensation considerations in crossover design and speaker placement...or just why it doesn't matter as much where you put a subwoofer, I guess.

Maybe all a moot point when just talking about little full range drivers crammed into an AIO that'd fall short of some $20 computer speakers though. /shrug

That's a valid point in a broader context of speaker design and soundstage. I'm afraid that in this particular context there's no special Dolby sound technology in play so far as I can tell, just mediocre built-in computer case speakers.

The only thing notable about the speakers on this early Intel iMac is that there's a little tunnel going all the way through the right speaker. At first I failed to understand why Apple decided to punch a tunnel through the right speaker but not the left. Could it be to bend sound waves? Some special type of audio encoding trick?

NOPE! None of the above. That little tunnel allows the characteristic pulsing light shine through when the iMac is asleep. This was part of the G5 iMac design which carried forward into the Intel iMac. The tunnel through the right speaker has nothing to do with sound. Apple just wanted a pulsing light there, and the speaker got in the way, so they just punched a tunnel straight through it! That goes to show how much of a priority the speakers were to Apple at the time. :lol:

Altogether, it's probably best to use an external sound device with the early Intel iMac.

isiolia wrote:Is the LVDS cable not the same on the LCD side as well? It doesn't seem like it's impossible to find third party control boards for the panels themselves, even if the connector Apple used on the motherboard side isn't standard. Hard for me to tell with the one I have...though I did pull it up from the basement, along with most of my other old computers. :lol:


You're absolutely correct about that, sir! Coincidentally, I continued the teardown process further last night to discover the connector on the other side of the cable. I will post more pictures later today to show everyone what I found.

Glad you pulled your iMac out of the basement. :mrgreen: Show that magnificent old beast some tlc. Embrace the love/hate relationship with Apple hardware design. :lol:
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Re: Early Intel iMac - Repair it or mod it?

by isiolia Wed Dec 20, 2017 10:34 am

samsonlonghair wrote:NOPE! None of the above. That little tunnel allows the characteristic pulsing light shine through when the iMac is asleep. This was part of the G5 iMac design which carried forward into the Intel iMac. The tunnel through the right speaker has nothing to do with sound. Apple just wanted a pulsing light there, and the speaker got in the way, so they just punched a tunnel straight through it! That goes to show how much of a priority the speakers were to Apple at the time. :lol:


Go back far enough, and they did put some real effort into making the little integrated speakers sound good. I think it was the Performa 6400 or so that had a ported speaker enclosure, to the point that it could act as a subwoofer if you used external speakers. I mean, it's still pretty relative. I'm sure the iMac ones are decent compared to a lot of other built-in speakers too.


The iMac, for me, is (I think) mostly a matter of whether or not I feel like sourcing a replacement panel (it's the AU brand one). Or, rather, if one can be sourced cheap enough for it to be worth bothering with, given what complete working machine goes for.
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Re: Early Intel iMac - Repair it or mod it?

by samsonlonghair Wed Dec 20, 2017 11:14 am

isiolia wrote:
samsonlonghair wrote:NOPE! None of the above. That little tunnel allows the characteristic pulsing light shine through when the iMac is asleep. This was part of the G5 iMac design which carried forward into the Intel iMac. The tunnel through the right speaker has nothing to do with sound. Apple just wanted a pulsing light there, and the speaker got in the way, so they just punched a tunnel straight through it! That goes to show how much of a priority the speakers were to Apple at the time. :lol:


Go back far enough, and they did put some real effort into making the little integrated speakers sound good. I think it was the Performa 6400 or so that had a ported speaker enclosure, to the point that it could act as a subwoofer if you used external speakers. I mean, it's still pretty relative. I'm sure the iMac ones are decent compared to a lot of other built-in speakers too.

No doubt about it, brother! My iMac G4 has incredible built-in sound. Even before I connected the transparent Harmon Kardon "soft ball" speakers, the sound built into that white dome really impressed me.

One of the big selling points for the legendary "Twentieth Anniversary Mac" was the Bose Sound System and CD-ROM. It reportedly sounds amazing... not that I have ever owned one... or seen one in real life. :lol:
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It's made of unobtainium!

I should probably clarify a point here: I don't hate the speakers in my early Intel iMac. Maybe calling them "mediocre" was too harsh. They're better than average built-in computer speakers. They're better than the speakers built into many consumer televisions. They're just not quite up to the standard Apple had set previously.

isiolia wrote:The iMac, for me, is (I think) mostly a matter of whether or not I feel like sourcing a replacement panel (it's the AU brand one). Or, rather, if one can be sourced cheap enough for it to be worth bothering with, given what complete working machine goes for.

You're astute to balance the cost/benefits. I can empathize with that. That's why I decided to tear apart a donor monitor rather than try to buy the official Apple replacement part. Here's hoping that doesn't come back to bite me. Knock on wood!
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Re: Early Intel iMac - Repair it or mod it?

by samsonlonghair Wed Dec 20, 2017 1:05 pm

Everybody ready? It's time for more pics!

I finished tearing the LCD out of my Early Intel iMac last night.
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In theory, it should still run like this if I plug a few power connectors back in and re-install the RAM module. That's not my goal for right now, though.

Remember that iSight cable that I couldn't disconnect before?
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It turns out that the connector was underneath the LCD. Now the cable comes apart easily without breaking. This looks similar to mini-USB to me, but I don't think it's the exact same. That said, System Profiler reports that the iSight camera is a USB device. I'm guessing the iSight communicates with USB protocols, but Apple is using a proprietary connector again. Apple's gonna Apple. :wink:

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Here's the back of the LCD panel after I disconnected it from the iMac. The black cable along the center is the LVDS cable. The wires on the side connect the lamps to the inverter board.

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Here's the model number and information from the back of the LCD panel. I mistakenly mis-reported the model number of this panel earlier in this thread. I'm going to go back and fix that post so I don't mislead anyone who finds this thread in the future.

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Here's a close up of the LVDS connection on the back of the LCD. I believe there is a controller board underneath that metal shield. Good news! This connector looks similar to the standardized form factor that LG used on other LVDS cables on other monitors. It's a thrity-pin connector with tiny metal clasps on either side. Those metal clasps are so tiny that I have a hard time even seeing them. I squeeze the diminutive metal clasps and IMMEDIATELY break them with my giant neanderthal hands! Hopefully those little clasps aren't necessary. :lol:

Overall, things are looking good right now! 8)
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Re: Early Intel iMac - Repair it or mod it?

by samsonlonghair Fri Dec 22, 2017 1:56 am

The sacrificial lamb is on the altar.
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This monitor is the LG Flatron W205TQ. I chose this monitor because it contains the exact same LCD panel as my 20" Early iMac. This is also the same LCD panel as the 20" G5 iMac. This LCD provides the rich colors that Apple displays are known for.

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Teardown is surprisingly easy here. Though the LCD panel is good quality, the enclosure is cheap brittle plastic. See that metal RF shield shaped like a trapezoid? There's not one single screw holding it in place. It was simply resting against the backside of the LCD. Once I remove the plastic shell, there's nothing to prevent the RF shield from sliding any which way.

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I separated the LCD from the rest of the monitor.

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These electric lines connect the inverter to the cold fluorescent lamps that light up this display. :idea:

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Here's the LVDS cable that connects to the back of the LCD. This ribbon cable transmits the low voltage differential signal from the small logic board to the LCD display. I'm hopeful that this will be compatible with the cable I pulled out of my iMac. Let's take a closer look for comparison.

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The Black cable under my thumb is the cable that connects the motherboard of the iMac to the LCD. You may recall that the other end of this cable uses a proprietary connector. The beige cable near my index finger is the one I just pulled from the LG Flatron. They're both 30-pin connectors. The cable from the iMac has those teensy little hooks, but the connector from the LG Flatron seems a little simpler and a little cheaper. These two cables aren't identical twins, but they could be brothers. :wink:

What do you guys think? Will I be able to utilize this monitor to fix my broken iMac? I'm going to give it my best shot.
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Re: Early Intel iMac - Repair it or mod it?

by CRTGAMER Fri Dec 22, 2017 10:23 am

samsonlonghair wrote:The Black cable under my thumb is the cable that connects the motherboard of the iMac to the LCD. You may recall that the other end of this cable uses a proprietary connector. The beige cable near my index finger is the one I just pulled from the LG Flatron. They're both 30-pin connectors. The cable from the iMac has those teensy little hooks, but the connector from the LG Flatron seems a little simpler and a little cheaper. These two cables aren't identical twins, but they could be brothers. :wink:

What do you guys think? Will I be able to utilize this monitor to fix my broken iMac? I'm going to give it my best shot.

One area to check if possible is the amp draw of each monitor. Should be similar, suspect the newer LG with more efficient circuits should have less amp draw.

There is a risk of blowing out your motherboard if the signals on that 90 pin all do not match. On the other hand, if the power lead is another isolated connection and the 30 pin strictly the low voltage signals, a better shot. Apple's reputation of proprietary a concern if all the pins are electric feed identical. A volt read of each pin from both the Apple and LG boards might help (at least to verify which the main power and ground), but then it is still a guesstimate.
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