Author Topic: US Duo Recap questions  (Read 305 times)

demianph

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US Duo Recap questions
« on: September 21, 2022, 10:37:38 AM »
So I pulled mine out of storage and opened the box and got a whiff of what I know is leaking capacitors.

Opened it up and I can see clearly 135, 149, 884, 322, 612, 616 323 have leaked.
Good news is nothing leaked through to the other side.
I've gotten the charts, read the a pinned post here and seen some youtube videos. I have a few questions.

My plan/observations.
  • I plan to do a complete recap. This includes the supercapacitor, all through hole caps that are electrolytic.
  • Wherever possible I plan to use same footprint surface mount electrolytic caps of the OSCON (or other non-leaking electrolyte type) since I do not feel like doing all the math to move to other surface mount types (found a page by TDK with a calculator for doing that) but I am not sure I trust my combined type ADHD riddled brain to get it right.
  • Some of the through hole types can also now be replaced with solid electrolyte caps.
  • Where possible keep to the same ratings as original parts (can go to higher voltage) as they have the same footprint still.
  • Plan to just use my weller iron station for isntall/removal as I have not purchased a hot air station as of yet.
  • Sourcing primarily from Mouser and Digi-key
My questions:
  • The pinned article says it's ok to use 16v caps even for the 35 volt ones but not the 50 volt one. That sets of alarms. I assume this has worked fine for everyone (I didn't notice anyone mentioning this in the thread)?
  • What are people doing for caps that are only available with liquid electrolyte? Just set a reminder for ~ 10 years for another recap?
  • Does anyone have a list for using other surface mount caps in place of the electrolytics (I know some are impossible to do this with because the packages are too big)? I'd like to re-cap this once and not have to worry.
  • I saw some terrifying video of using pliers and pushing down while twisting laterally or using wire cutters to just clip the caps off the board. This doesn't work safely/reliably (especially with electrolyte eating the board) does it?
  • Besides the jailbar fix (I know I need this) what other mods are worth doing while I am doing al this.
  • I have an OSCC so was thinking of the RGB mod but I also have the composite/svideo to rgb module for the OSCC so maybe I can just get an svideo cable for the unit?
  • I was looking at the vram upgrade but I think that needs to be a longer term project as I will need to get a few items to support that process.
« Last Edit: September 21, 2022, 12:28:53 PM by demianph »

demianph

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Re: US Duo Recap questions
« Reply #1 on: September 21, 2022, 02:37:19 PM »
Managed to identify that almost all the SMD aluminum caps on Duo board are Panasonics. according to older datasheets for SMD electrolytics the top is capacitance the next line is voltage (with a note that 6=6.3V)  and then series letter (either A or S) the bottom line is lot code. All are 2000 hour 85C 20% tolerance. I think this is most likely the same for all the other caps.
I think the ones that have the top line start with an actual manufacturer mark that looks like a V with a line over it are Vishey but have not been able to confirm. Values are clear on it.
There is a single cap with another manufacturer mark  and probably lot number as the top line, it's values are also clear.
Super Capacitor (C509) is an NEC 5.5v .047F (47000 uF)
« Last Edit: September 21, 2022, 05:04:25 PM by demianph »