CRU hardware

Discussion on CRU hardware


I found a slight issue with the usb connector for the internal USB Blaster on the CRU.
The connector is mounted 2-3 mm too far from the edge, such that the USB cable won’t fit in a way that the spring mechanism is doing it’s job.
I tried illustrating the issue with the below picture, where you can see the red line representing the spring – the “hook” of the spring is resting on the front metal part of the USB connector and won’t go into the little crevasse where it is supposed to hook the cable, and you get a very poor connection, and a cable that might fall out just by random vibration.

Here is also a picture of how it looks from the outside:

And an attempt at making a diagram with some caliper measurements.


Normally a the mini-B “barrel” sticks about 1.5 mm out from the edge of the connector when it has a good contact. In this case it sticks out by ~3.6 mm, enough to not give a secure contact.

Ciao Lars … we have USB cables already “properly” modified to fit in the CRU + SERVER setup.
I think they are stored in the room behind the window.
I brought them @ P2 when we moved all the machines there.
(Anyway if they are not there I have plenty in the CRU lab)

The modification consists in cutting most of the plastic covering the USB connector … after that if fits properly.

We had similar issues like that in the past with cables and connectors not fitting properly.

Let me know if you want to do more tests.


Ciao Pippo,
That’s cool, then can I take four of these and plug into our CRUs?
For now I put enough tension on the cables that the USB Blasters are at least recognized and I could program all four cards with the latest firmware from the upstream master branch.

Will this “hack” be a final solution? I haven’t been following the issue with programming the CRU through PCIe, so if this is something that will be fixed in the future, then the whittling solution is good enough for now, at least for me.


Ciao, the “hack” (cutting the cable) is the final solution to have the USB well plugged in.
The PCIe programming is still on the table. There are some issues with Intel and we are in contact with them … so we didn’t give up yet.

I’ll check where the cables are and give them to you.