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Any ideas on what needs replacing on this Duo 230 LCD panel

OleLila

Well-known member
I have changed out a backlight from a bad LCD to a good looking LCD. It looks good for about 30-45 seconds...then flicker to stripes , then eventually to grey (no mouse). I am 90% sure it is on the LCD panel itself as the prior LCD panel worked fine..it just had a big red spot in the middle.Are capacitors on the LCD screen the source and do people replace these with any luck?IMG_4875.jpg

IMG_4876.jpg

 

OleLila

Well-known member
Sorry...I didn't look back far enough before posting. Will replace caps on LCD.(searching screen and account options..do not see an option to delete post either.. again I apologize)

 

superjer2000

Well-known member
I'm recapping my Duo 230 - I had recalled reading about the capacitors in the screen but I'm pretty sure they are tantalums and so I wasn't planning on replacing them (screen worked fine last time I used the machine).  @OleLila what prior thread did you find regarding caps in the screen being a problem?  I searched but came up empty handed since I have it apart, I might just replace them anyways.

For others, I'm pretty sure these are tantalums but I thought I'd confirm (sorry about the bad picture quality):

IMG_4223.JPG

 

OleLila

Well-known member
The posts I found were actually in regards to capacitors on the non-duo capacitors and they are not tantalums. Because the back light was broken, but the LCD worked, I theorized the screen had been dropped. When I tapped on the capacitors (as you have pictured) two did indeed move (and the pads looked coroded). I was feeling bolder than my skills should have allowed and replaced the captors...I think it worked except in the process I over heated the lower corner of the screen and ruined the LCD. The lower left is blacked out with red dendrites on the non functioning portion.

 

superjer2000

Well-known member
@OleLila Do you have any part numbers for the capacitors you ordered?  I'm having a hard time figuring out what is functionally and physically equivalent to what is in there now.

 

techknight

Well-known member
I'm recapping my Duo 230 - I had recalled reading about the capacitors in the screen but I'm pretty sure they are tantalums and so I wasn't planning on replacing them (screen worked fine last time I used the machine).  @OleLila what prior thread did you find regarding caps in the screen being a problem?  I searched but came up empty handed since I have it apart, I might just replace them anyways.

For others, I'm pretty sure these are tantalums but I thought I'd confirm (sorry about the bad picture quality):

View attachment 25042


They are most certainly NOT tantalums. they are plastic encased aluminum electrolytics. you can see the corrosion where they need changed. 

 

OleLila

Well-known member
"encased aluminum electrolytics"...that must be what I'm seeing...if you look at the non soldered end you can see the capacitor and this explains why the pad areas are so corroded on some of them. I used the capacitors from another screen that was damaged. Again...the LCD is right there and, not sure how easily can be damaged by  the heat of the nearby soldering.(because it took me a while,sorry for the repost of a picture already at trading post).

IMG_4880.jpeg(

 
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Byrd

Well-known member
I'd say you have a couple of problems with the LCD there, regardless of replacing the caps - damage on the flex cable/connector and algae bloom (the red growth on the left)

 

techknight

Well-known member
The picture above is a damaged LCD. the glass is physically cracked in the corner = trash. 

Dont pull used caps. replace them with new. if you replace them with one from another LCDs your stuffing in bad for bad. 

 
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Trash80toHP_Mini

NIGHT STALKER
It may be trash, but what a beautiful colored pattern!

I've been working on a Shoji screen to hide the hack bench and panels covering storage next to it in the living room my apartment as that area morphs Washitsu. I'm looking at traditional cherry blossom art for the large panel, but this makes me want to go digital brightness instead. Probably too loud for for a smallish home theater setting though. :/

But maybe as a cover panel for part of the HackSpace storage?

I wish I had as tall a pile of Duo's as the 1400 stack so I could spare one. Sorry about yours, but man is that gorgeous! I was thinking CPU die art before this, thanks for the pic.

 
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superjer2000

Well-known member
Thanks all. I've picked out a few suitable replacement caps (different shape but should fit). I'll update once everything is changed out the the Duo is back together. 

 

superjer2000

Well-known member
They are most certainly NOT tantalums. they are plastic encased aluminum electrolytics. you can see the corrosion where they need changed. 
Yup - That was 100% correct.  The caps were just tiny little electrolytics in a small square case.  They were definitely leaky as well.  I was able to break the legs off super easy by just rocking the little boxes back and forth.

Underneath was definitely some corrosion as techknighted noted.

IMG_4375-small.jpg

Still, everything cleaned up nicely

IMG_4378-small.jpg

I used a damp shop cloth as a heat sink to avoid damaging the LCD.  I'm not sure this was necessary but I a previous post made me think it would be better to be safe then sorry.

I replaced the leaky electrolytes with some small MLCCs:

IMG_4380-small.jpg

As the MLCCs have exposed ends and there is some metal shielding that overtop, I used some paper as an insulator.

IMG_4381-small.jpg

I recapped the logic board and then put it all together (after breaking a few clips due to the brittle plastic (but it still holds together perfectly)).  Taking this machine apart is a royal pain...

And it booted up right away!

IMG_4383-small.jpg

When I plug it in, it makes a small high pitched noise at first.  I think it always did this to be honest but I'm not too interested in troubleshooting it now.  At least the caps aren't going to leak anymore given that they were replaced with polymer and ceramics.

These are the Mouser caps I used:

810-C3216X7R1V335M6A x 8 (MLCCs for the display)

647-PCV1V101MCL1GS x 3 (100 uf 35v 10mm)

647-PCJ1C331MCL1GS  x 1 (330 uf 16v 10mm)

647-RHS1V101MCN1GS x 2 (100 uf 35v 8mm)

667-25SVPK33M x 1 33uf 25v

 

OleLila

Well-known member
That looks great. Thank you for the update. I used two soldiering irons to remove the caps on the LCD, I would vouch for rocking for removal and using a heat sink. Still kicking myself for the loss of a good LCD.

 
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