R-Pi B+ Problems

I have been having problems with a Rasberry-Pi B+ running RISC OS. The first microSD card from ROOL got completely corrupted. They replaced it: this did not cure the problems (though they seemed better). ROOL said it had t be a hardware fault, so I got the R-Pi B+ replaced by Farnell. The problems are still present.

There are essentially two problems:

Firstly: SD access is very flaky. During Boot, the Pi will report disk errors from certain programs, but checking these after booting, they run fine and no disc error can be found. Also, when saving to the SD card, the Pi will often report a disk fault. Usually DiscKnight will find no fault, though sometimes there is a disk corruption. Occasionally the freespace map will be corrupted.

Secondly: The mouse behaves erratically: mouse clicks are often not registered – I have counted up to seven clicks before one registers. Double clicking has little chance, unless the clicks are very widely spaced.

Sometimes a mouse click will be held until the mouse is moved slightly, when the click is registered. This is particularly noticeable on drag and drop: the dragged item sticks to the mouse pointer when the button is released and does not drop until the mouse is moved slightly.

Sometimes a whole string of clicks will be discharged, stopping only when the mouse is moved.

Both behaviours may be slightly better with the latest combination: certainly th first SD card was completely corrupted by the first R-Pi. But the problem persists even having rep;aced SSD and R-PI.

So it seems there is a software problem combining with the hardware – or maybe the Pi’s firmware. To me, it seems like a timing problem. It is inconsistent: sometimes it is much less noticeable that at others. Maybe these problems are specific to the B+ or were they also present on the earlier R-Pi and are much worse on the B+.

Has anyone else experienced similar problems?

Since I can’t get RSS feeds from this forum with Hermes, please email me: Riscos@Torrens.org.uk

I think this could be a power supply problem. When I got my B+ I bought a 2.1A 5v power supply – the type with a USB socket in the plug – and when I first tried it it was flakey – though not as bad as you describe. I tested the voltage on the 5v pins and it said 4.9V changing the USB power lead from the plug to the pi from a 1.8m one to a 1m one upped the voltage to 5v and I haven’t had problems since.

Adding USB devices causes the voltage to drop and if it drops too far the mouse starts to miss clicks again. Except for the keyboard and mouse I tend to use a powered hub for USB devices.

I think this could be a power supply problem. When I got my B+ I bought a 2.1A 5v power supply – the type with a USB socket in the plug – and when I first tried it it was flakey – though not as bad as you describe. I tested the voltage on the 5v pins and it said 4.9V changing the USB power lead from the plug to the pi from a 1.8m one to a 1m one upped the voltage to 5v and I haven’t had problems since.

I’ve read various articles on the subject of USB lead power delivery and most often it comes down to cheaply made leads with dreadful loss levels. Note that general experience is that two cables from the same supplier may not be the same manufacturer or quality.
I think there’s a market for a Pi carrier board that has a powered USB hub to increase the available USB ports and a decent power input socket. Minimal components and minimal cost.

Steve: The x100 board achieves this (amngst other things).

I have just measured the voltage on the micro USB power input. 5.13v.

On the GPIO pins there is 5.07v.

So it doesn’t look like any of the problems I have are power supply! However I have just ordered a 5v 8 amp supply which I will connect via the GPIO.

The supply I have is rated at 2 amps. Apparently there is a 2 amp polyfuse on the board – though that was for the original Pi. Not sure about the B+ – I can find no documentation for it.

All models before the B+ had a 1Amp PolyFuse
The B+ has a 2Amp PolyFuse

Schematics for all models inc B+ are here