Have i broken it?

[Scuzzy47]

Recently I bought a protoboard for my 40x + an lcd display... It worked like a charm till yesterday. I started soldering the last wires, as I was finishing it... then suddenly I tried my program again, nothing. I tried downloading it again, but says it can't find the hardware, and I didn't change anything...
Anything I can do about this accept buying a new one?

 

[ylp88]

Since the problem ocurred after soldering, try checking the board for bad soldering joints - even a missed solder joint. Make sure that they are all nice and shiny.

If worse comes to worse, try thowing the PICAXE chip onto a breadboard and seeing if the chip will accept a program without the PCB. If so, the problem is on the board and it's time for a good look at tracks, soldering and connectors. If not, the chip may have died and consequently need replacing.

Also check the power supply to the PICAXE - make sure that it is receiving a nice steady supply. Also check that the resonator is fitted and is secure and that the reset resistor is functioning by checking the voltage at the reset pin - it should be close to +5V.

Just try a bit of elimination...

<b><i>ylp88 </b> </i>

 

[Scuzzy47]

I hooked up a computer PSU to it, to give it a steady voltage, and I'm using the 28x/40x protoboard, with the resonator already in place, so the voltage can't be the problem... It must have something to do with overheating, I assume. Because before me soldering some wires to the board, everything worked like a charm, and now it won't process, so no leds are lighting and the lcd doens't work, and it won't let me download to the chip.
I'll try the homemade pcb thing as soon as I get the right resistors, but probably my chip is wrecked...
I guess the only solution will be ordering a new one. It ain't cheap, but I need it for my schoolproject...
Thx for your help, I'll get back on you as soon as I tested it on the pcb...

 

[Fowkc]

I'll beat Stan to this one:

Remove the computer PSU and use 3xAA batteries. New AA batteries. While a computer PSU might seem clean enough, batteries are cleaner. And it just removes one more complication, which is vital for fault-finding.

It does sounds like the soldering has killed something, but for testing purposes, stick with the batteries until your issues are solved.

Edited by - Fowkc on 20/04/2006 23:50:33

 

[ylp88]

Perhaps I was not clear: do NOT use a PBC, rather, find a breadboard and set up the basic circuit on that:
- PICAXE chip
- Download resistors
- Resonator (if applicable)
- Pull-up reset resistor (if applicable)
- 3 x 1.5V batteries

If that works, then you should start looking at your PCB as the culprit. Overheating may be an issue but, in my opinion, is often overconsidered. If you are using IC sockets on your PCB then the problem is even less likely as the ICs are the ones which are most sensitive. Resistors and wires etc... (generally non-semiconductors - ICs, transistors, diodes) are generally more robust.

<b><i>ylp88 </b> </i>

 

[manuka]

I've said it all before concerning breadboards, so how about a different tune -ESD or stray voltages on the s/iron tip? Most electronic components can take 5 secs of soldering iron temps OK, so doubt if you've cooked the Picaxe-40 that way. Stan

 

[whizzer]

Following on from Stan&#8217;s useful reply.

Stray voltages at the soldering iron tip can indeed be a damaging force -especially with an iron that has a mains-powered heating element. All it takes is to have an imperfection in the grounding of the frame of the iron and.. -nasty things can happen. And all of this made worse in countries which have mains power in the region of 220-240 volts, as compared to the US&#8217;s 110 volts.

Unfortunately hobby &amp; electronic parts shops are only too willing to sell these types of products without question to unknowledgeable students.

The other thing no one has mentioned so far is the possibility of linking two adjacent solder pads together with an un-intentional solder bridge. Sometimes it can take a shape that can cause one to think that the link is supposed to be there.

Can any of us actually say we haven&#8217;t done this at some point in our lives?

 

[andrewpro]

A &quot;Horror story&quot; on the bad thigns that can happen with solder...I had a small &quot;hair&quot; of solder connecting two pads once. After tearing out my hair, tripple inspection under a magnifying lense, desoldering a good portion of the board, replacing about a dozen caps, and still having issues I busted out the microscope and finally found the thing. It had partially melted itself into the PCB (no solder resist on this one) and even though I had cleaned betwen everyhitng, it managed to hold on. It couldn't have been thicker than a half a human hair, but it was causing everything to go wonky and not work at all.

I dunno how it got there, but the evil little thing cost me two nights of aggrivation. Just something to look out for <img src="wink.gif" width=15 height=15 align=middle>

--Andy P

 

[Scuzzy47]

so to put the download circuit on breadboard, i just need a 10k, 22k and a resonator? what about the voltage, just connect it to a V+ and 0V pin on the picaxe?

 

[Scuzzy47]

and are thetere any pins that need to be connected, except for the resonator pins, the voltage pins and the serial I/O ?

Edited by - scuzzy47 on 21/04/2006 14:54:32

 

[Dippy]

Print out the pages 19, 20 and 21 from the Getting Started pdf manual.
See how the components are connected.
Don't forget the pull-up resistor for the reset pin.
Have you got the right value resonator?
Take the above advice re: batteries.
Ditto sticking it in breadboard.
Treble check your conenctions.
Check your batteries and polarity.
And have another go at downloading something.

Edited by - dippy on 21/04/2006 15:17:41

 

[Scuzzy47]

Thx, I hadn't tried that circuit, but I've done al you advised and still no luck.
I'll just buy another one I guess...
Thank you all for your help
Grtz