Display died

[Legodude522]

The display on my 1ghz Pandora appears to have died. Tried all of the usual stuff like power cycling and removing battery. From how the LEDs are acting, it looks like the Pandora is booting but the LCD is just completely dead, no display and no backlight. Any ideas? Is this simply a cable that needs to be reseated? I wasn't exactly gentle with it since I use it for work on smoke stacks but there has been no direct impacts to it.

 

[levi]

Check it's not simply the backlight that's gone; shine a torch onto it and see if you can see anything. If it is just the backlight it could conceivably be the cable at fault, but more likely the units shaken a coil loose. If it's completely dead, seems like a cable's become unplugged. The easiest side to get to is the bottom layer if you remove the screws from the base and open it that way, although it's possible it's become unclipped from the other end.

 

[TeDaDeS]

If it's the coil you can get a repair here: https://dragonbox.de/en/after-warranty-repairs/pandora-coil-replacement-no-backlight-on-lcd.html
Or if you are handy fix it yourself by re-attaching the coil. The coil/inductor is 22uH (part number: LPS4018-223ML).

 

[Legodude522]

Thanks all. Upon close inspection, the LCD was working but the back light was off. I opened up the Pandora and the first thing I saw was the coil hanging off.

Would this be an appropriate replacement? https://www.mouser.com/ProductDetail/Coilcraft/LPS4018-223MRC?qs=QQJxVsr8EGZ1iTyTHMP0jg==

 

[levi]

It's probably the same part, but I don't see the need to buy one because the one you've already got is very unlikely to have broken. Fitting it again is a bit tricky becase it's a surface mount part so the contacts are on the bottom of it. If you already have a hot air rework station then it might be worth having a go, but otherwise I'd suggest paying for ED to fix it for you and shipping it back there.

 

[Legodude522]

It's probably the same part, but I don't see the need to buy one because the one you've already got is very unlikely to have broken. Fitting it again is a bit tricky becase it's a surface mount part so the contacts are on the bottom of it. If you already have a hot air rework station then it might be worth having a go, but otherwise I'd suggest paying for ED to fix it for you and shipping it back there.

I wonder what turnaround time is these days. I'm considering buying a hot air rework station.

 

[Letalis Sonus]

because the one you've already got is very unlikely to have broken.

I guess that depends on whether the visible shape on the solder pad is the imprint of the coil - or the coil's own pad that broke off. I'd say the latter looks more plausible.

 

[TeDaDeS]

I wonder what turnaround time is these days. I'm considering buying a hot air rework station.

You could always find someone near that is handy with soldering these kind of components. If the coil isn't broken it probably still works. But the coil itself is cheap to buy, if you repair it I would place a new one anyway.

Shipping it to ED, waiting for the fix and shipping it back will probably take a while. Especially if you live outside of Europe.

 

[levi]

I guess that depends on whether the visible shape on the solder pad is the imprint of the coil - or the coil's own pad that broke off. I'd say the latter looks more plausible.

Hmm, that is possible, although I've more commonly seen the pads on the motherboard lifted with the component with learner solderers. Never seen the component come apart and leave parts of it's guts on the motherboard. But either way round complicates the repair I guess.

 

[Git1]

This is why I love the Pandora/Pyra project. Could you imagine asking A@#$e about such a problem? Well done guys.

 

[TrashyMG]

I think in these cases the solder joint was the weak spot, likely size of the part didn't allow for proper heating of the pads and created a weak bond.

 

[TeDaDeS]

Thanks all. Upon close inspection, the LCD was working but the back light was off. I opened up the Pandora and the first thing I saw was the coil hanging off.

Would this be an appropriate replacement? https://www.mouser.com/ProductDetail/Coilcraft/LPS4018-223MRC?qs=QQJxVsr8EGZ1iTyTHMP0jg==

Yes, LPS4018-223MRC is the same part as LPS4018-223ML.
The RC at the end (R, which was L) means they switch to a new 'termination' (Matte tin over nickel over silver) and the C means which type of reel is used (which is only interesting when doing mass production).

More info: https://www.coilcraft.com/en-us/pro...ductors/ferrite-drum/lps/lps4018/lps4018-223/

 

[Legodude522]

Yes, LPS4018-223MRC is the same part as LPS4018-223ML.
The RC at the end (R, which was L) means they switch to a new 'termination' (Matte tin over nickel over silver) and the C means which type of reel is used (which is only interesting when doing mass production).

More info: https://www.coilcraft.com/en-us/pro...ductors/ferrite-drum/lps/lps4018/lps4018-223/

Good information here! Thanks. I ordered the hot air station and the coils.

 

[TeDaDeS]

If you just reseat the original coil you might get away using nothing additional.

with a new coil you probably also want:
Flux, makes your solder flow better.
Solder paste, which works well with hot air, it also makes the coil stick to the board. Don’t use too much, else solder balls will fly over the board (usually easy to remove though).
Isopropyl alcohol for removing flux after you are done.

 

[Legodude522]

So I finally got around to replacing the coil. I struggled with the hot air soldering gun. This didn't work out. The original solder seemed to make a new high temperature alloy with the solder I was using. I moved to a traditional soldering iron, cleaned things up, and then was able to solder on the new coil. The LCD now works! My poor case is starting to show it's age though, at least two of the case screw holes are stripped.

 

[TeDaDeS]

So I finally got around to replacing the coil. I struggled with the hot air soldering gun. This didn't work out. The original solder seemed to make a new high temperature alloy with the solder I was using. I moved to a traditional soldering iron, cleaned things up, and then was able to solder on the new coil. The LCD now works! My poor case is starting to show it's age though, at least two of the case screw holes are stripped.

Good job

 

[Legodude522]

Proof that it now works

 

[netcat]

xscreensaver -root .... hell yes