Fixing the Unfixable iMac Pro with Louis Rossmann!

[Emily Young]

It couldn’t end any other way than this. Louis Rossmann is here to FINALLY attempt a repair of our iMac Pro – But will it actually work?

 

 

Got an iMac of your own that needs fixing?
Buy an iMac opening wheel from iFixit: http://geni.us/lQFu
Buy iMac display adhesive strips from iFixit: http://geni.us/dA9uuc

 

Check out Louis Rossmann's channel: https://www.youtube.com/user/rossmanngroup

[WereCatf]

I don't particularly like Rossmann as a person, but I have watched plenty of his videos just to learn a little, pick up some of his nifty little tricks. They guy does know what he's doing, alright.

 

EDIT: I just started watching the video and I just gotta comment on it, even if I'm still at the beginning: it's pretty shitty, how Linus just begins to talk over Louis, and Louis's jabs/Apple-jokes are getting cut off by editing. That's really bothersome and seems quite disrespectful.

[BlueChinchillaEatingDorito]

I think the title should be... Two Chucklefucks try to assemble an iMac Pro back together. 

[Stefan Payne]

Pretty anticlimactic.

Louis wasn't really Louis and Linus was a bit too alpha.

[dizmo]

Louis was awfully quiet. Not sure if it was just his mic or how he was the whole time, but it was hard to pick up a lot of what he said.

Reminds me a lot of Joe Rogan's role in this:

http://www.comedycentral.co.uk/chappelles-show/videos/great-new-york-boobs-uncensored

[BlueChinchillaEatingDorito]

14 minutes ago, dizmo said:

Louis was awfully quiet. Not sure if it was just his mic or how he was the whole time, but it was hard to pick up a lot of what he said.

Reminds me a lot of Joe Rogan's role in this:

http://www.comedycentral.co.uk/chappelles-show/videos/great-new-york-boobs-uncensored

Maybe he's like that when he's working with people he's not used to on camera. Was like that during the WAN Show with GN, and Jayz and Linus's trip to his shop.

[NMS]

You wouldn't have to go through all that if you wouldn't have bought it in the first place.

Nice series, but it only made me hate Apple even more. Wasn't sure if it could've been done, but I guess everything is possible:D

[Nicnac]

I kinda dislike Louis these days but I have been waiting for this video nonetheless  

[Unimportant]

Can't help but notice the Rigol in the background. Perhaps some interesting project(s) in the pipeline ? Or is that just there to show off to Louis seeing he's got an older model

[WereCatf]

6 minutes ago, Unimportant said:

Or is that just there to show off to Louis seeing he's got an older model

No way Linus would be that petty.

 

 

....what? He would? Oh, well then..

[Sakis]

you should use a volt-meter and check the caps plz, if they are still charged apple is more BS than they could ever be, first year in electronics engineering and they teach people about "bleeding" resistors, that should discharge caps within 10mins MAX when unplugged so plz check it out for me (but be extra careful).

the shielding could stop EMI from the transformer except just protect people so IF they have such a resistor they should still have it.

you should also check if this thing really Fcc and ce compatible

[Guest]

Louis was being quite polite in the video and props to him. I was pretty disappointed with Linus' behaviour like, we want to watch a video on rebuilding the iMac Pro, not a running commentary on previous videos and a very lengthy rant. It's OK when it's like a minute or two, but 8 minutes in till getting to it, it's a bit of a yarn. It's fine to express your opinion, but it gets a bit old when you say the same thing over an over. To be honest I thought Louis was pretty patient. 

[geo3]

Wait. You fly him in to assemble a Mac? Why not have him attempt to repair the damaged board? 

[D13H4RD]

Did he say the system has a 500W power supply?

 

For a Xeon and a Vega 56/64?

[Aprime]

11 hours ago, WereCatf said:

I don't particularly like Rossmann as a person, but I have watched plenty of his videos just to learn a little, pick up some of his nifty little tricks. They guy does know what he's doing, alright.

 

EDIT: I just started watching the video and I just gotta comment on it, even if I'm still at the beginning: it's pretty shitty, how Linus just begins to talk over Louis, and Louis's jabs/Apple-jokes are getting cut off by editing. That's really bothersome and seems quite disrespectful.

If we're talking cut content it's mostly from Linus' side. I don't really understand your perspective. 

[FlanK3r]

Part about PSU, lol

[suicidalfranco]

To all those who said it can't be done

 

Spoiler

ligma

 

[NeverGoIntelKKThx]

i have a better idea

 

get - a - p c

[Ashley MLP Fangirl]

i really didn't like that video. the constant apple jokes were really annoying. 

i don't like most of LTT's video's these days but this one was particularly bad. 

[Sauron]

19 hours ago, dizmo said:

Louis was awfully quiet. Not sure if it was just his mic or how he was the whole time, but it was hard to pick up a lot of what he said.

Reminds me a lot of Joe Rogan's role in this:

http://www.comedycentral.co.uk/chappelles-show/videos/great-new-york-boobs-uncensored

 

19 hours ago, Stefan Payne said:

Pretty anticlimactic.

Louis wasn't really Louis and Linus was a bit too alpha.

Louis is probably not used to this format, his videos are mostly him ranting over a motherboard or an article looking straight in the camera and barely having to interact with anyone. Also I guess Linus had more things to say on this particular topic considering all the drama over his imac.

[mariushm]

16 hours ago, Sakis said:

you should use a volt-meter and check the caps plz, if they are still charged apple is more BS than they could ever be, first year in electronics engineering and they teach people about "bleeding" resistors, that should discharge caps within 10mins MAX when unplugged so plz check it out for me (but be extra careful).

the shielding could stop EMI from the transformer except just protect people so IF they have such a resistor they should still have it.

you should also check if this thing really Fcc and ce compatible

These days, modern switching power supplies no longer use plain bleeding resistors to discharge the primary capacitors, because they're trying to get the efficiency of the power supply as high as possible. Plain bleeding resistors can in some power supplies cause maybe something like 0.1% loss in efficiency because the capacitors are constantly discharged in the resistors.

So in modern power supply there's a special tiny chip which sits between the capacitors and the discharge resistors and monitors the mains voltage. When psu is turned off the chip enables itself and creates the connection between the primary capacitors and those resistors and the capacitors discharge. When the psu is turned on, this chip detects this and disconnects the bleeding resistors so there's no losses.

 

Modern power supplies also use mechanical relays to short circuit  resistors or varistors which are installed before primary capacitors to reduce inrush current. When primary capacitors are fully discharged and the power supply is turned on, the capacitors simply suck in a lot of energy at a high current rate, which can cause the fuses in your house panel to think there's a short circuit somewhere and trigger. By installing a resistor or varistor, the current is limited and the primary capacitors charge at a slower rate. So power supply turns on, the resistor or varistor limits current and capacitors charge quickly but at slower rate (instead of let's say 5 ms, they charge in 100ms) and 1-2 seconds later, a circuit in the power supply turns on a mechanical relay which shorts out that resistor or varistor, taking it out of the circuit so it's no longer heating up and cause efficiency losses.

 

So anyway, chances of getting zapped by charge in capacitors nowadays is fairly low, and most power supplies should be safe after around 10s or so after you remove the mains cable. Still it doesn't hurt to be careful, though you don't need to be paranoid about it.

 

-

 

Yeah, Louis was a bit "shy" ... maybe he wasn't used to all the fancy RED cameras and lots of lights (you can see he's blinking a lot in the video, maybe nervous reaction or just sensitivity to light). But he gets a pass from me, it's not his kind of content, he's more technical and doing repairs, this video was more or less an ikea video, a "let's assemble this", no repairs.

 

 

[Zodiark1593]

20 hours ago, dizmo said:

Louis was awfully quiet. Not sure if it was just his mic or how he was the whole time, but it was hard to pick up a lot of what he said.

Reminds me a lot of Joe Rogan's role in this:

http://www.comedycentral.co.uk/chappelles-show/videos/great-new-york-boobs-uncensored

Given I've watched both LTT and Louis Rossmann for some years, their interaction and roles were about what I expected. Louis doesn't strike me as a particularly vocal person outside his own profession. Linus by comparison is very much into the show business. Neither were particularly well versed in assembling an iMac.

 

That "fan spin" bit was pretty great though. And at least the danger of the exposed PSU was covered.

[Guest]

12 hours ago, D13H4RD2L1V3 said:

Did he say the system has a 500W power supply?

 

For a Xeon and a Vega 56/64?

And what is wrong here?

[Unimportant]

46 minutes ago, mariushm said:

These days, modern switching power supplies no longer use plain bleeding resistors to discharge the primary capacitors, because they're trying to get the efficiency of the power supply as high as possible. Plain bleeding resistors can in some power supplies cause maybe something like 0.1% loss in efficiency because the capacitors are constantly discharged in the resistors.

So in modern power supply there's a special tiny chip which sits between the capacitors and the discharge resistors and monitors the mains voltage.

Happen to have part numbers for such a chip? I've never seen something like that before, and I fix a lot of SMPS from all kinds of fields.

 

52 minutes ago, mariushm said:

Modern power supplies also use mechanical relays to short circuit  resistors or varistors which are installed before primary capacitors to reduce inrush current. When primary capacitors are fully discharged and the power supply is turned on, the capacitors simply suck in a lot of energy at a high current rate, which can cause the fuses in your house panel to think there's a short circuit somewhere and trigger. By installing a resistor or varistor, the current is limited and the primary capacitors charge at a slower rate. So power supply turns on, the resistor or varistor limits current and capacitors charge quickly but at slower rate (instead of let's say 5 ms, they charge in 100ms) and 1-2 seconds later, a circuit in the power supply turns on a mechanical relay which shorts out that resistor or varistor, taking it out of the circuit so it's no longer heating up and cause efficiency losses.

Haven't seen a computer PSU using relays for ages now. I'd like to think a good PSU exploits the inertia provided by the APFC inductor to limit current peaks without resorting to clunky relays.

[Zodiark1593]

Petition for Linus to pay for Louis to go to Improv school?