CM3 board doesn't fit with L2/R2 thumbsticks board

[StonyYodelers]

Hey all,

I just got my Freeplay CM3 today, and started building it. After installing the extra board for the thumbsticks and L2/R2 buttons I wanted to test the fit of the cm3 board in the header because it looked tight. I've double checked the installation of the thumbsticks board and it is installed correctly.

I can't push the right side of the cm3 down far enough to engage the clip to hold it in place. U1 and Q1 on the thumbstick board push against the pre-installed heatsink on U2 on the back of the pi.

It looks like if I remove the heat sink it would just barely fit, but that seems like a dubious thing to try without confirming it's the correct thing to do first. 

I did order the optional fan as well, I wonder if that is provided to assist with cooling because of that heat sink removal...

[StonyYodelers]

Update:
I removed that heat sink just so I could finish the build and test, but I still have the heatsink and can pick up the thermal tape from digikey for like a buck if I need it.

I just plan on not playing it until I know for sure.

I'm fairly confident I did the right thing though, as it doesn't seem physically possible for it to fit otherwise

[Flavor]

If I understand correctly, you are talking about a heatsink that was on the Compute Module itself, correct? That heatsink was facing toward the Freeplay circuit board, right?

This is not standard. There were a handful of modules like that which had heatsinks pre-applied. I thought that these had been fully tested and checked out to make sure that nothing was impeding them. I guess that it wasn't fully tested with the add-on board.

We've had HUGE problems obtaining parts lately. Raspberry Pi Compute Modules are sold out all over the place. We ended up buying some that were intended for a different purpose (in a computing cluster) and the guy installed these heatsinks. Then, I think he scrapped the cluster idea, so we bought the modules from him.

We do not typically install the heatsinks. They are not needed for the Freeplay CM3. I'm sorry that you had to deal with that, but it's safe to remove them. I'll make sure that no others go out like that. They were just left on, because there seemed to be no good reason to remove them. Not I know that there IS a good reason.

Ugh. It's been very frustrating trying to get Freeplay CM3 boards and then find out that Raspberry Pi modules are hard to obtain. Sigh.

[StonyYodelers]

Yep, the one facing the freeplay board is the one I was referring to. I think for most cases it won't be an issue for a customer, might even be nice to have another heatsink on there for anyone just making a base freeplay cm3. But with the L2/R2 slim dual analog board it doesn't fit.

I work for a company that makes motion controllers, and I'm on the circuit building/repair side, we've been getting hit with part shortages too so I feel ya lol. One part we have on order has an eta of August. in 2023! lmao

I think you guys could go either way, leaving them on or taking them off since it might be a fairly rare problem. But if you leave them, I would just add a note or something somewhere mentioning that if you get that slim add on that you need to remove the heatsink. Though, I'm a little concerned about someone not used to this kind of work being too rough when removing it and accidentally damaging the chip. Iirc it was a bga chip and those are a pain to resolder even if you know what you're doing lol

[Flavor]

We will just remove them. They're not necessary, and I don't want anyone yanking on the BGA chips.

I'm glad that it was you that had the problem, but I'm also sorry that you, on a personal level, had to deal with it. At least you recognized the need for proper handling and how to do that properly.

The part shortage thing is just crazy. There are SEVERAL parts that we've had to find alternative sources for or had to find alternate parts for, and I feel like it's not getting better anytime soon.