New G4 Cube picked up as part of package deal with Studio CRT (ADC)

[wottle]

Found a listing for a cube and studio CRT ADC and the owner wouldn’t split them apart. I already have a working Cube but always wanted the CRT to go with it. Bit the bullet and bought the bundle, figuring i could sell the cube myself and it’d basically be like I just bought the monitor.

Went to pickup and to my surprise, as it wasn’t mentioned in the listing, the cube came in the original box. It’s not perfect, has duct tape over it and the UPC has been cut out (thanks CompUSA rebates!), but has all the accessories.

Now I’ll figure out which Cube is in the best shape, keep it and the box and sell the worse of the two.

Unfortunately, I think the power supply has a short. When I plug in the AC cord, I see a spark. Any ideas on how to get it apart to see what is happening?

I know the cube itself and the CRT are fine because I was able to use my existing power supply and it runs fine. Planning on swapping out the HD for an SSD and go from there. Would really like to be able to sell it with a working power supply, though. (technically I have a spare power supply, but it goes with my Dr Bott DVIator, so I'd like to keep it).

 

[Certificate of Excellence]

Wow, very cool I love the look of those crt studio displays as well - by far the coolest CRT design ever in the history of CRTs. Always wanted one myself but haven't run into one. Occasionally, I notice the PSU on my B&W does the same thing where it momentarily sparks when plugged in. Im unsure what the specific cause is but assume there is a short somewhere in the circuit.

 

[nottomhanks]

Very cool!! I have a G4 Cube and that CRT, but I don't have the acrylic base for it!!

 

[Philgxxd]

A box fell onto my power supply and damaged one of the two plastic clips that holds the front panel onto the casing as shown on the photo.
I could get into it because of that missing clip quite easy and glued the missing peace back into place and didn’t get further as mine still do work.
At least it shows you the location of the plastic clips where you should start to open it up.
Good luck!

 

[wottle]

That looks like it will be a blast trying to get the latch to pop free. Thanks for the image. I read something about trying to get something through one of the tiny holes to pop it loose. Feels like I'm headed into broken plastic territory...

 

[Certificate of Excellence]

I think I would have left mine broken just for ease of access Trying to get that thing off without breaking a tab seems like an almost impossible feat but I can see per wottles reply that you might be able to fish a piece of wire around the clip and then pull back on it enough to release it from the chassis. If I did manage to get it off, Id certainly leave a little wire in there just to make disassembly easier and faster moving forward.

A pain in the butt for sure, but I still want one

 

[fehervaria]

Maybe you can try acetone to melt the plastic (ABS) and glue the two parts together? Won't be 100% like was before but can be better than any other glueing method. I saved few vintage CRT Monitor housing with this way and last as it should. Could help here too.

 

[davidg5678]

I just used a small piece of clear tape to hold the PSU back together after this clip snapped. I figure that I'll probably need to repair it internally someday anyway, and having a small piece of tape on the box I place on the floor never bothered me very much.

 

[kimahlberg]

@Philgxxd did you manage to repair your G4 Cube PSU?
I have two of these PSUs, both no longer functional, that I'm trying to figure out how to coax back to life in order to put my Cube back in service.

I recall visiting a defunct website called CubeOwner where someone mentioned a capacitor would fail and need to be replaced or re-soldered in these PSUs, but I can no longer find any information online about how to go about it. Any insight you might have would be appreciated.

 

[François]

Another (more expensive) option is to replace the innards of the Cube PSU with a modern open frame 28V 8A (convection cooled) power supply. It will easily fit inside the original shell, be more efficient and produce less heat.

 

[kimahlberg]

Another (more expensive) option is to replace the innards of the Cube PSU with a modern open frame 28V 8A (convection cooled) power supply. It will easily fit inside the original shell, be more efficient and produce less heat.

That's an interesting idea! This sounds like something I would absolutely want to do to one of mine if it provides a reliable PSU for my Cube.
Are there instructions anywhere on how to do that?

 

[Philgxxd]

@Philgxxd did you manage to repair your G4 Cube PSU?
I have two of these PSUs, both no longer functional, that I'm trying to figure out how to coax back to life in order to put my Cube back in service.

I recall visiting a defunct website called CubeOwner where someone mentioned a capacitor would fail and need to be replaced or re-soldered in these PSUs, but I can no longer find any information online about how to go about it. Any insight you might have would be appreciated.

Sorry, mine isn’t broken. It just got that plastic tab snapped when a box fall onto it.
I can’t help you there.

 

[François]

That's an interesting idea! This sounds like something I would absolutely want to do to one of mine if it provides a reliable PSU for my Cube.
Are there instructions anywhere on how to do that?

I don’t recall seeing a write up, but you basically just need to figure a way to mount the new PSU inside the shell and wire the connector as follows:

A = +28V
B = +28V
C = Common (or - side of supply)
D = Common (or - side of supply)

the outer shell of the connector is ground

 

[kimahlberg]

Sorry, mine isn’t broken. It just got that plastic tab snapped when a box fall onto it.
I can’t help you there.

I don’t recall seeing a write up, but you basically just need to figure a way to mount the new PSU inside the shell and wire the connector as follows:

A = +28V
B = +28V
C = Common (or - side of supply)
D = Common (or - side of supply)

the outer shell of the connector is ground

View attachment 10150

Ok, that seems doable. Thanks for the information.
I'll try it after the holidays, and if I manage to make it work I might write a blog post about it to help others.

 

[wottle]

I don’t recall seeing a write up, but you basically just need to figure a way to mount the new PSU inside the shell and wire the connector as follows:

A = +28V
B = +28V
C = Common (or - side of supply)
D = Common (or - side of supply)

the outer shell of the connector is ground

View attachment 10150

Yeah, I ended up following the guide that picture is from: https://www.edretrotech.com/2021/02/power-mac-g4-cube-power-supply.html

Works well, but not an original look because the PSU is too long to fit inside with the 3d printed extender. My fit wasn't perfect, so I have some white electrical tap holding things together.

 

[François]

An open frame PSU will be smaller. You don’t need the shielding, the Cube PSU shell will provide it.

The Mean Well EPP-400-27 will fit inside, I think:

EPP-400-MEAN WELL Switching Power Supply Manufacturer

MEAN WELL is one of the world's few standard power supply mainly professional manufacturers, covering 0.5 to 25,600W products are widely used in industrial control, medical and other fields, in line with international safety certification, short delivery of spot inventory.

www.meanwell.com

 

[wottle]

An open frame PSU will be smaller. You don’t need the shielding, the Cube PSU shell will provide it.

The Mean Well EPP-400-27 will fit inside, I think:

EPP-400-MEAN WELL Switching Power Supply Manufacturer

MEAN WELL is one of the world's few standard power supply mainly professional manufacturers, covering 0.5 to 25,600W products are widely used in industrial control, medical and other fields, in line with international safety certification, short delivery of spot inventory.

www.meanwell.com

I think you're right. That one would likely be a much better choice. I checked the casing on mine and it looks like the usable space inside is about 6.5" long, by 4" wide, but 2" tall. The EPP-400-27 appears to be 5.00" L x 3.00" W x 1.38" H.

You think the 27V would be OK given the Cube is expecting 28V?

 

[François]

I believe this PSU output voltage is (slightly) adjustable. You can have it output the proper 28V. But the Cube should be fine with only 27V: It converts it internally to 12, 5 and 3.3V

 

[SteveHere]

@Philgxxd did you manage to repair your G4 Cube PSU?
I have two of these PSUs, both no longer functional, that I'm trying to figure out how to coax back to life in order to put my Cube back in service.

I recall visiting a defunct website called CubeOwner where someone mentioned a capacitor would fail and need to be replaced or re-soldered in these PSUs, but I can no longer find any information online about how to go about it. Any insight you might have would be appreciated.

I’m also a Cube owner and the person I bought mine from also mentioned the CubeOwner site. at least some of that content has been captured in the wayback machine…

CubeOwner.com | A Heaven For Cube Owners

Sadly i do not see anything specific about the Power Supply capacitors.