Case assembly first impressions

Banana Pi Router design
1

Hi folks.

I feel like its time for a positive post, so here goes;

I’ve finally had time to assemble my bpi-r4 into its case for a trial fit.

The case looks really smart.

The fit and finish are very high quality, with everything lining up beautifully. All the ports and slots sit dead centre in their cutouts, and not one thing needed to be forced into position. Very impressive indeed.

The heatsink/fan however is junk. There is a slight design issue at play here - the two mounting holes are not centered over the MCU, and this is obviously why it is shown in the instructions with two thermal pads on the bottom of the SDRAM chips, as this enables it to sit flat (ish) over the MCU.

This is, at best, a poor workaround, so i’d recommend finding an alternative arrangement.

If the heatsink supplied actually covered the RAM properly it would maybe be ok, but it doesnt.

Ive left it off (for now) as under light-medium loads, it runs cold anyway.

If future board revs had 4 mount points for the heatsink, rather than 2 off-centre ones, this would be a huge plus, and allow far greater flexibility.

The case has nice crisp markings, including footprints for the 3M branded rubber feet, which is a lovely touch.

A small rubber bung to cover the boot switch hole would be nice, but not required, as the switches are recessed a sensible amount.

Personally, i’d have preferred the sim trays to be black alloy finish too, but thats nothing a light dusting with a bit of paint can’t fix.

Lastly, I really like that they give you plenty of screws. Mine came with 2 spare case screws, and two spare mounting screws for the board, AFAICT. It also came with 6 screws for the pcie slots.

Oh, and it’d make getting the lid on easier if it had a slight chamfer on the corners, but that hardly matters

IMG_20240706_141555
IMG_20240706_1415551920×1444 87.5 KB
IMG_20240706_142758
IMG_20240706_1427581920×2553 93 KB
IMG_20240706_142833
IMG_20240706_1428331920×1444 148 KB

All in all, a really nice bit of kit. I will be getting it for my other r4 units, assuming the WiFi 7 boards are as good as promised (I don’t have one yet)

2

I have ordered this fan. It also covers the ram ICs and fits perfectly. Click

3

Ill have to post a slight correction…

I actually have the fan you pictured. It does cover the RAM. I’d assumed it was the one pictured, as they do look nearly identical, but again the pictures fail to match the product…

As least the unit shipped is /better/ than pictured this time.

My criticism of the mounting system remains valid, however; the off centre holes place the onus on the thermal pads to keep the MCU in good thermal contact with the heatsink, and the pads are /very/ thick.

Its quiet enough, but I still don’t like it. Its cheaply made, and there is plenty of room in the case for something much much nicer.

A shame, given how nicely made the case is.

4

The official heatsink /w fan from Banana PI should cover the two RAM chips fully. I don’t have it but I saw it before.

This is very trivial nitpick. The current layout is fine. With a mindset of PC overclockers, many ppl emphasised cooling the two RAM chips. IMO, they don’t need any cooling on BPI R4. So 2-3mm thermal pads not an issue.

I used 1.5mm on the RAM chips, 0.75mm on the SoC. Don’t care about the eMMC chip at all. My heatsink happily rests on top…flat secured with two push pins

If I’ve to make a further MOD, I would want to replace the push-pins with spring screws. A little bit more pressure on the heatsink surely help.

But also many ppl simply let the heatsink rest on the chips with sticky tape. SBCs like BPI R4 is very easy to cool. One way or other doesn’t produce much difference in terms of cooling effect.

5

Ideally, id like to see 4 mounting holes, and for the case to have screw lugs below them.

I wouldnt increase the spring pressure over the existing heatsink - the problem is that increasing the force on the existing mounting points causes the flat bottom of the heatsink to tilt towards the ram, which makes it lift off the cpu (it rocks, because its off centre)

Its “fine” as is, with light pressure, because the fairly thick pads squish only a little.

Theres a reason most laptop cpus have 3 or 4 mounting points…

I really dont want to complain too much about this though. As mentioned before, the majority of the mechanicals are spot on, and the tolerances are excellent in general.