Rag-time4's Duo repair project

[rag-time4]

I've finished replacing 90% of the caps on the board (doing total cap replacement) but one of the first ones I removed I am so far unable to replace. My problem cap is one of the 10uf caps near the sound amp. I have removed all the solder from the board and can't get new solder to attach to the board, and therefore can't get a replacement cap to stay in place. Here are a few pics:

If anyone has any ideas on how I can replace the solder please share!

[ogre]

Unfortunately it looks as if the surface mount pad is completely gone. The only possible solution may be to see if you can find the trace to it and solder that. First and foremost I would clean off the surrounding used flux to get a better view. There is a repair kit method
http://www.engineeringlab.com/smtpadrepair.html but it seems way to involved and expensive.

[nat]

Oh yeah, once you rip off that solder pad you're fucked. I've done it many a time myself. Your only hope is to follow the trace and hope it leads somewhere close you can use as an alternate solder point.

[rag-time4]

Some new pics:

[Turbo D]

Grab a multi-meter and follow the trace of where the solder pad used to be (use the continuity setting, looks like this: -l>l-))) .) I imagine you can follow it to one of those holes that are in close proximity. If one of those holes works out, then you've scored as you can run one of your cap legs through it and solder away. Good luck friend. =D

http://www.ladyada.net/library/metertut/continuity.html

[kattare]

I had to get out my duo to trace the lead, but it looks like you can solder the pin into the hole that breaks up the cap outline.

-----X--
|           \
|            |
|           /
---------

About where the X is in my diagram, relative to your photos.

[Charlie]

If that circuit is the same as the TE (anyone know for sure?), go here:

https://www.pcengine-fx.com/forums/index.php?topic=702.msg116301#msg116301

Charlie

[rag-time4]

I had to get out my duo to trace the lead, but it looks like you can solder the pin into the hole that breaks up the cap outline.

-----X--
|           \
|            |
|           /
---------

About where the X is in my diagram, relative to your photos.

Your diagram is a reproduction of the white outline that surrounds the missing cap, right? If so, the hole at your X is traced to the positive connection, there is another hole Y traced to the negative connection:

-----X--
|           \
Y           |
|           /
---------

I've put both legs of the cap through these holes, and attempted to solder them down. I'll post pics after dinner.

[rag-time4]

pics of the new 10uf cap in place:

[chop5]

took me half a day to do this:


http://img.photobucket.com/albums/v238/jetbue7/childdrawing.jpg


but i see others are on the same page 

[kattare]

chop!  love it!  heh

[esteban]

chop!  love it!  heh

Excellent diagram, pithy advice

[rag-time4]

I've got everything back together, but when I turn the Duo on, I get a grey or brown screen and an audio hum from the tv. Chop has recommended checking all caps for continuity. Anyone have any thoughts?

EDIT ~ I have 2 loose caps... gonna get those tightened and re-test.

EDIT II ~ All loose caps have been tightened... I found reversed polarity on one of the 47uf caps near the red led and fixed that. I've checked for continuity and everything looks good... but the 10uf cap that I had to emergency solder through the holes does not give me as much continuity with itself as the other 10uf caps. There is still some continuity, however. With the top half of the case off, I can see the CD ROM spindle start to spin, and I see a blink from the laser. Also, the screw holding down the white and green wire on the left side of the CD Rom broke off. These wires are normally secured to the metal around the CD spindle by a ring terminal, but since the top of the screw came off, the ring terminal can't be attached.

[kattare]

Can you confirm, with no card inserted, you do not get the usual bios screen?

Does anything change if you insert a card and boot up?

What process did you use to clean up the cap leakage prior to installing the new caps?  I wonder if you might still have a short somewhere from the leaked fluid.

[rag-time4]

Can you confirm, with no card inserted, you do not get the usual bios screen?

Does anything change if you insert a card and boot up?

What process did you use to clean up the cap leakage prior to installing the new caps?  I wonder if you might still have a short somewhere from the leaked fluid.

Correct, I do not get the usual BIOS with no card inserted. I get a grey or brown screen and an audio hum from the tv with no card inserted. If I insert a US hucard, sometimes I'll get different color screens (as in solid in colors other than brown and grey) but I'll get the same audio hum.

I used a moist cleaning towelette to remove the old cap juice that had leaked, and I also used a q-tip dipped in alcohol and dry q-tips to clean excess flux around the pesky 10uf cap in chop5's diagram.

Note: before my attempt at cap replacement, my problem was faint CD audio. Sound FX and other functions of the DUO were fine.

[kattare]

Yikes, I hope the reverse polarity on that one cap didn't cause more damage.  If you powered it on with the polarity reversed there's a 90% chance that cap is bad now tho.  You're lucky it didn't blow up on you.  ;-)  You'll want to snag a new one and try again I think.

[rag-time4]

I've installed new 47uf caps, but I'm getting the same symptom: solid color screen with audio hum.

I notice that if I insert a HuCard, I can see some scrolling on screen. There is a horizontal section slightly darker than the rest which scrolls upward.

[D-Lite]

I've installed new 47uf caps, but I'm getting the same symptom: solid color screen with audio hum.

I notice that if I insert a HuCard, I can see some scrolling on screen. There is a horizontal section slightly darker than the rest which scrolls upward.

Does it change with HuCard?  All the indications are you've got a short somewhere.

[rag-time4]

I've installed new 47uf caps, but I'm getting the same symptom: solid color screen with audio hum.

I notice that if I insert a HuCard, I can see some scrolling on screen. There is a horizontal section slightly darker than the rest which scrolls upward.

Does it change with HuCard?  All the indications are you've got a short somewhere.

Dean, the change is only slight. With or without hucard I get a solid color screen with an audio hum. The only change is that with a HuCard, there is a slight scroll in the video. It's like there is a horizontal bar that is slightly darker than the rest of the screen. The dark part scrolls upwards. With no HuCard, there is no scroll.

[kattare]

I hate to say it, but you may have to go through and pull out your caps, test 'em, check the board out, and re-install 'em.  Not that I think a bunch of 'em are bad, but I think your board may need an inspection for shorts and/or cuts/breaks.

[rag-time4]

I hate to say it, but you may have to go through and pull out your caps, test 'em, check the board out, and re-install 'em.  Not that I think a bunch of 'em are bad, but I think your board may need an inspection for shorts and/or cuts/breaks.

Kattre, I think you're right. I pulled 3 caps near the sound amp, but I'm gonna stop here and send the Duo over to chop before I cause any more damage. Hopefully he can get it back up and running.

[Duo_R]

The new 10uf cap should only affect your sound circuit, that shouldn't be causing the no screen issue. however, you do want that cap correctly installed. Once technique I used when I first did this install and lifted the solder pad was I passed through the cap legs through to the bottom of the Duo PCB, and on the underside I reconnected that cap to pad that traced and was more easier to solder to. Take a look on the underside and see if you can find a point like that.
                ____
                |    |   <--- 10 uf Cap
                |__ | 
                 |   | <--- Cap leg
     =========|=========== <--- PCB
                     
                     /\
                      l
                      l
              Apply Solder Here
 
So you would apply the solder on the underside when the cap leg passes through a small hole (usually where the original cap passed through)

[rag-time4]

The new 10uf cap should only affect your sound circuit, that shouldn't be causing the no screen issue. however, you do want that cap correctly installed. Once technique I used when I first did this install and lifted the solder pad was I passed through the cap legs through to the bottom of the Duo PCB, and on the underside I reconnected that cap to pad that traced and was more easier to solder to. Take a look on the underside and see if you can find a point like that.
                ____
                |    |   <--- 10 uf Cap
                |__ | 
                 |   | <--- Cap leg
     =========|=========== <--- PCB
                    
                     /\
                      l
                      l
              Apply Solder Here
 
So you would apply the solder on the underside when the cap leg passes through a small hole (usually where the original cap passed through)

I got that 10uf cap through the proper holes... but the soldering got a bit messy. In the process of working in that area I may have damaged traces as well.

[NecroPhile]

I got that 10uf cap through the proper holes... but the soldering got a bit messy. In the process of working in that area I may have damaged traces as well.

Stop!!  This is the e-police!  Put down the soldering iron and step away from the PCB. 

It's a bit too late for your Duo-R, but you (and anyone else with a similar lack of experience) might be better served by practicing your soldering skills on a few junk PCBs before risking damage to something good.

[D-Lite]

I got that 10uf cap through the proper holes... but the soldering got a bit messy. In the process of working in that area I may have damaged traces as well.

Stop!!  This is the e-police!  Put down the soldering iron and step away from the PCB. 

It's a bit too late for your Duo-R, but you (and anyone else with a similar lack of experience) might be better served by practicing your soldering skills on a few junk PCBs before risking damage to something good.

I've been cringing through this thread as well.

[kattare]

Heh, I gotta give the guy credit for tryin' tho.  How many other folks just throw away stuff like this?

[DragonmasterDan]

Heh, I gotta give the guy credit for tryin' tho.  How many other folks just throw away stuff like this?

I ruined a Turbo Express (it wasn't lighting up anyway) and several game gears trying to soder.

[D-Lite]

Heh, I gotta give the guy credit for tryin' tho.  How many other folks just throw away stuff like this?

Oh, I agree.  Still makes me queezy.

[rag-time4]

I got that 10uf cap through the proper holes... but the soldering got a bit messy. In the process of working in that area I may have damaged traces as well.

Stop!!  This is the e-police!  Put down the soldering iron and step away from the PCB. 

It's a bit too late for your Duo-R, but you (and anyone else with a similar lack of experience) might be better served by practicing your soldering skills on a few junk PCBs before risking damage to something good.

Chop told me to practice soldering on junk boards.... Unfortunately I don't have a lot of junk boards laying around. I think I got a lot out of the experience.... now hopefully my Duo can be salvaged!!

[Duo_R]

Part sale! Part sale!

[kattare]

Speaking of part sales!  I have a duo for sale, ok, sort of a duo... call it frankenduo... cuz just about every single mechanical part has been swapped out of it as I've been using it to fix other duos.  I'll take a pic of it one of these days.  It's grrrrrreat.  When I'm all done repairing my current batch of duo's I'll take lots of photos, write up a detailed description, and put it on ebay... see if there are any takers.  ;-)

[Duo_R]

I need the part BU4053BF off a "junked" board....

[chop5]

took me a while but i got it working. Its out of the duo hospitals icu and getting ready for release.
Redid that whole trouble area before i ran out of 22uf and 100uf caps.


The rest of rags work was crude but acceptable so i plugged it in for test run. Everything works hucard and cd.
Did some longevity tests with multiple games,hu and cd buns and real for 2 hours with no difference. Wasn't hot to the touch and laser noises searchings and busy were normal. Compared it to my duo and no difference. Sound is crisp and regular and fmv runs smoothly. Did notice slight whistling on laser showing signs of early laser wear,but wont need to replace for a long time still.
Don't know what else i can do with it. Will do a few more days of hard play then pack it up for return

[rag-time4]

took me a while but i got it working. Its out of the duo hospitals icu and getting ready for release.
Redid that whole trouble area before i ran out of 22uf and 100uf caps.


The rest of rags work was crude but acceptable so i plugged it in for test run. Everything works hucard and cd.
Did some longevity tests with multiple games,hu and cd buns and real for 2 hours with no difference. Wasn't hot to the touch and laser noises searchings and busy were normal. Compared it to my duo and no difference. Sound is crisp and regular and fmv runs smoothly. Did notice slight whistling on laser showing signs of early laser wear,but wont need to replace for a long time still.
Don't know what else i can do with it. Will do a few more days of hard play then pack it up for return

Chop have you tested the saved game function? That's one thing I'm wondering about. Was the save memory wiped and does the feature still work?

[NecroPhile]

Congrats on saving rag's Duo from the scrap heap. 

[kattare]

nice work chop.  ;-)