TSGL: Mobile phone - hope someone can help with this

[H Davis]

Heidi,

The link you copied is missing some characters in the middle where the 
... is. I think it should be:
http://www.blue-backlight.de/de/umbau_de/SiemensSX1/umb_sx1_11.jpg

and the forum page that references it is:
http://translate.google.com/translate?hl=en&sl=de&u=http://www.mobil-talk.de/benq-siemens/691-sx1-wiederbeleben-alle-tricks-versucht.html&sa=X&oi=translate&resnum=1&ct=result&prev=/search%3Fq%3Dhttp://www.blue-backlight.de/de/umba%2Bumb_sx1_11.jpg%2B%26hl%3Den%26safe%3Doff%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26hs%3DHTJ%26sa%3DG

I tried the Google translate function on the (german?) forum but it 
still made little sense to me.

 From the picture there appear to be only 2 areas on the side of the 
board that's shown that you could hope to repair by re-soldering; the 
large shiny circular area at the top and the double row of 8 in the 
lower left. These 2 rows could be the flash memory you refer to but who 
knows. The large shiny circle is probably not the flash memory. Try 
looking on the other side of your board for any components with writing 
and see if you can deduce which is the flash memory chip. Someone else 
on this list might be able to tell you, more specifically, what to look 
for - nomenclature, size of chip, arrangement of pins, etc.

A cold solder joint often looks dull, and perhaps slightly granular, 
compared to the usual shiny color of a good solder joint. However, after 
a period of use the shiny joints will have become somewhat dull also, 
making this method of distinguishing the bad one iffy at best.

If it once worked and now has failed, you might detect a crack in the 
blob of solder using a magnifying glass. Again, no guarantee. Cold 
solder joints can appear perfectly normal and yet make no connection 
between the pin and the copper circuit material. That's what makes them 
extremely difficult to find. Most folks will just re-solder all the pins 
in the suspect area and hope for the best.

As far as the hair dryer goes, I have real misgivings about that. First, 
I don't think a regular hairdryer will get hot enough and second, it 
will heat a big area risking damage to a lot of components. The aluminum 
foil you mention is probably an attempt to prevent this.

I suggest getting a soldering iron, around 25 watts, with a small 
conical tip. Use rosin core solder or solid core solder with separate 
rosin flux. Don't use any acid based flux. Here in the US you could get 
all that for about $10 at Radio Shack. If you don't feel up to that task 
take it to someone who has experience soldering; a friend, a technician 
at a computer store that does repairs, etc. If you can point at what you 
want soldered he could do it in about 10 minutes. There's no guarantee 
that it will work but it shouldn't cost much.

Soldering on these small circuit boards requires some skill because 
overheating will easily damage the components and an unskilled repair 
person can easily overheat the component he's (she's) trying to repair.

If you decide to try it yourself I can expand on these instructions but 
the key, of course, is to correctly identify the faulty connection, if 
that's the problem.

Good luck,

H Davis

Computerfee wrote:
> Hi there everybody,
> My husband is trying at last to repair the old mobile phone of our son which is a Siemens SX1. We found online, the solution for the problems seems to be a cold solder joint of the Flash Memory on the printed circuit board which you have to re-do. Now the problem is our lack of knowledge where to find the point where it has to be done. The description of the repair is rather vague - wrap plastic-part of two plug-connections with aluminium foil, put some solder on the edge of the printed circuit board and heat it up with a hair drier until it gets liquid. Well, nice clear - the edge of the thing could be anywhere. here is a link to the photo of the printed circuit board in question it is part of a description for changing LED colours, so that's why these spots are marked - http://www.blue-backlight.de/de/umba...umb_sx1_11.jpg Maybe it is not on this side even but on the back of it, but I could not find anything else but the description above and the forum where I found it, seems to be quite old, as the mobile is quite old as well. 
>
> So I am just hoping anybody around does have an idea that could help us here.
> Thanks a lot
> Best wishes 
> Heidi
>
>
>
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-- 
H Davis   hdavis1 at gmail.com