PR2-2 I2C Shield for Raspberry Pi 3 & Pi2 with Outward Facing I2C Port Not working with RPI 3 b+

The above product seems to work with Raspberry PI 2 and RPI3. However, with a RPI 3B+ (latest) won’t boot. I am worried that I will run out of stock for RPI 3 standard since that is what happened with the RPI2.
Any fix for this?

We just found out that Pi3B+ 3.3V regulator has some issue. we have designed new pi shields which will not depend on pi 3.3V supply and will have their own 3.3V regulators.
This new shield will work with all pi modules including Pi3b+.
It will be available in a couple of weeks.


OK thanks–
Please identify the new part number with a suffix or rev number or something so we can order the correct part.



I have struck the same issue.
What is the problem with the Pi 3B+ regulator?


Hi Dazz,
the regulator is not powerful enough to deliver the current neccsery to run any IO lines.
Our new pi shields come with 3.3v regulator and they will work will all pi models.


Is the new part available yet?

Can you provide a link?

Yes, it is.

You can get any one of these.


Ok that’s great. I purchased a bunch of these a few months ago to use with pi 3B+ boards. Is there any replacement program, trade in, etc?

Also, if I understand correctly, the old shield worked on the 2 and 3, but didn’t work on the 3B+? Is that right? It might be a good idea to mention on the product pages that it now works with the 3B+. What is the policy on the 3B, with respect to the old and new shield?

I am currently using a 3B with an old board, but I seem to frequently be getting SD card corruption - could it be related to using the old shield?


You can return the old shields if they were bought within last 1 month.
SD card corruption is a well known issue with Pi ( its more of a SD card issue) . Shield has nothing to do with SD card or any other interface of the Pi.

I just recently got one of the suggested updated i2c boards, but it still fails to work on both a RPi B3+ and a RPi 4.

On the RPi 4 having the shield connected prevents it from booting, presumably by pulling on the 3.3 or 5v too hard. If I connect the shield after boot, however, it doesn’t halt the system.

Unfortunately on both Raspberry Pi boards it doesn’t actually carry the SDA/SCL signals at all. I can put a digital debugger on the pass-through pins (3 & 5) and see the signaling. If I hook the debugger to the NodeLynk socket wires…nothing.

Do I have a defective part, or is there something else I should try?

Edit: as is tradition around here, I’m including a photo of the setup, although the problem reproduces with just the shield + Pi.

This shield is not tested with Pi4 but works fine with Pi3b+ and lower models.

Did you enable the I2C ?

What the voltage at i2c port SDA and SCL lines?


That’s what I was hoping, but is not working fine on the Pi3b+ I’m testing it on right now…

i2c is enabled on the Pi. To reiterate, I can actually read the i2c pins (3 & 5) on the Pi itself working with a Saleae Logic debugger when I issue i2cdiscover -y 1. I can also read them working on the pass-through pins 3 & 5 on the shield, but I can not read any signaling on the shield’s NodeLynk socket leads.

When idle, I have 5.1v on the SCL and 4.5v on the SDA on the NodeLynk socket. On the RPi pins, I have: 3.7v on the SCL and 4.4v on SDA.

does it scan correctly if you install the shield once pi boot up.

No, it does not scan on either the RPi 3b+ or the RPi 4, regardless of if the shield is attached before or after boot. Attaching it after boot to the RPi 4 allows the Pi to continue running, but does not make the i2c shield work.

you can connect the i2c board directly with pi like this
Board ==== Pi
5V ----- 3.3V

and run i2c scan command. This will eliminate the i2c shield from the equation and will tell us rest everything is working

OK, I bypassed the shield, as advised, and am now connecting the Pi 3b+ directly to the 4-20mA Current Loop Receiver.

The receiver can now be communicated with, and responds on i2c port 49. So, looks like a bad shield?

looks like shield is not working. You can submit an RMA over here

ps – i will unplug the setup because right now it s using pi 3.3V supply and it doenst have enough power to support I2C devices.

Should I move it over to the 5v supply pin - I understand it won’t have the boost cap, but that should be “better”, right?

Noo… That will pull the I2C to 5V and that could damage your Pi.