STM CircleOS forum / Primer2 Dead.. :(

repzak · 2009-03-01 22:17:33

Hello..

My Primer just died (less than1 week old), the U9 regulator gets very hot, but regulate nice until it shuts down for temperature...

In the time the voltage is ok, all things seems to be ok, picture on screen, backlight, music..

but then after 1-2 sec it turns off and start blinking, due to temperature of U9.

Some one have a good clue where to start error searching?

My primer was modified before i recieved it with U9 bug.

I think it is not in software since it only starts circle_os.

I think these are the devices on 2V8:
IRDA
U16
Codec
STM32
RLINK

Someone have seen the same?

Kasper

Francis · 2009-03-02 06:50:12

Yes, I reproduced the same issue by touching with my finger the board. I discussed with ST about this issue. Their recommendation was an optimized routing and the replacement of the C23/C56 capacitors (tantalum) by ceramic capacitors.

repzak · 2009-03-02 07:11:30

Hello,

Thank you for your quick response...

So, mine will not get working again as before, so some parameters in some componment must have changed...

Was your reproducing permanent or only when you touched?

mine is permanent, so i need to do something, you suggest to change the capacitor?
which value does these capacitors have?

Kasper

repzak · 2009-03-02 18:49:50

Up running...

Added a 3V3 lowdrop regualtor with a diode on the output instead U9 until i get the correct regualtor... it gives 2.6V so the volt measurement in the uC is proberly uncorrect...

Kasper

zysko · 2009-04-01 13:29:18

Hi,

It happend to me as well. Then I noticed that my Primer2 have already changed regulator and extra ground is added to it. Do you know what is the reason for it? Will it help if I install a hat sink or should I replace it to more robust device.

I am doing as well a extension board. Would it be better idea to power Primer2 (2.84V and 5V) from external source?

Regards,
Grzegorz

Francis · 2009-04-01 14:52:31

The conclusion from ST has been:
1. enforce the ground,
2. replace the tantalum input capacitors by ceramic ones (for C56 and C23).
3. they sent me various advices to optimize the routing. One of them was to keep not too close the two regulators (it seems that the noise generated by each regulator could be a problem for the other).
If #1 is not sufficent, try #2.
BTW, we have seen that:
a. the problems occurs often when we 'touch' the PCB.
b. more often when the consumption is high=> we reduce the backlight current and the volume on the LS and it seems much more difficult to kill a regulator, even when touching the PCB... .

# 1 2009-03-01 22:17:33 Primer2 Dead.. :(

Primer2 Dead.. :(

# 2 2009-03-02 06:50:12 Primer2 Dead.. :(

Re: Primer2 Dead.. :(

# 3 2009-03-02 07:11:30 Primer2 Dead.. :(

Re: Primer2 Dead.. :(

# 4 2009-03-02 18:49:50 Primer2 Dead.. :(

Re: Primer2 Dead.. :(

# 5 2009-04-01 13:29:18 Primer2 Dead.. :(

Re: Primer2 Dead.. :(

# 6 2009-04-01 14:52:31 Primer2 Dead.. :(

Re: Primer2 Dead.. :(

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