Products > Test Equipment

FNIRSI-1013D AS MUCH USE AS A CHOCOLATE FIREGUARD.

<< < (16/18) > >>

perdrix:
Less use than a chocolate fireguard (you can after all eat the chocolate fireguard)!

D.

Gannet:
That's a good Idea, that way no one will be able to trace where it's gone. Trace he he  :-DD

pcprogrammer:
Received the patient and started investigations on it.

Apart from the inverted display there is also a, what looks like, random resetting of the processor. Some relays click, the screen goes black and the current drops. The screen going black is due to the brightness signal being turned off, but there are also moments that it stays on and the screen is just white.

Think this has to do with how far the processor can run through the code before running into trouble. The strange bit is that sometimes it starts up fine and works stable for a while, but eventually it turns of again.

The current is around ~350mA when the back light is off and no activity on the LCD signals, around ~750mA when the back light is on, but still no activity on the LCD signals. It goes up to ~1A when it is working.

The MCU clock shows normal signs of live, and the voltages are up to par without garbage on them. My guess is that the MCU is broken somehow. Ordered up a new one and when it arrives, I will see if it is indeed the culprit. It is a bit of a challenge with the ground pad, but some youtube videos show it can be done with just a hot air station.

pcprogrammer:
Unfortunately I messed up. QFN is not my thing. The old one came of easily, but I did not notice that a pad also came of :palm:

Tried to solder the new one on and the solder did melt and the ground pad made proper connection, which can be measured via small copper bits on the corners of the chip, but I think a lot of the pads did not. My hands are also not so steady anymore so while trying to tap it down it moved of the pads  |O

Finally managed to get it straight and under a microscope it looked like the pads had connections after multiple attempts with a soldering iron running past them, but it is dead. So either I fried the chip or there are still some bad connections. I can see on a scope that the clock is running, and on startup there is some activity on the SD card signals.

So I have met my match.  :-[

The picture shows the pad that came loose.

Chris02:
Hey pcprogrammer,

cool project to make a new firmware for the scope!

If you want post or send me some high resolution pics and I can try to check the soldering.
And did you check the current consumpting after changing the cpu? It maybe should give you some hints, e.g. if there is any short shircuit from soldering.

I also has got one question. Supports you firmware (I guess original one doesn't do) simple "+" operation? I have to check some RS485 signals and need to add CH1 and CH2.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod