Electronics > Repair

repair: 3com Baseline Switch - model 2808

<< < (2/2)

PedroDaGr8:
Retiredcaps  is correct.  The Nichicon issue is unrelated to the bad caps issue though the symptoms are the same.  For the bad caps, cheap electrolyte breaks down eventually venting and killing the cap.  For the Nichicon caps, they accidentally over filled the caps with electrolyte.

Bored@Work:

--- Quote from: What_NZ on June 19, 2014, 03:46:45 am ---Shown below are the Nichicon capacitors that have failed, I hope you can see the bulging top. I have ordered some excellent quality Panasonic's but the unit is working perfectly with some temporary one's.

--- End quote ---

What? You are substituting parts? Hahaha.

What_NZ:

--- Quote from: Bored@Work on June 21, 2014, 04:47:40 am ---
--- Quote from: What_NZ on June 19, 2014, 03:46:45 am ---Shown below are the Nichicon capacitors that have failed, I hope you can see the bulging top. I have ordered some excellent quality Panasonic's but the unit is working perfectly with some temporary one's.

--- End quote ---

What? You are substituting parts? Hahaha.

--- End quote ---

Huh? and what is wrong with replacing 1500uF 6.3vDC 105C low ESR capacitors with 1500uF 6.3vDC 105C low ESR capacitors. If you are going to post something at least try to make it intelligent.......

What_NZ:

--- Quote from: retiredcaps on June 19, 2014, 05:48:36 am ---
--- Quote from: What_NZ on June 19, 2014, 03:46:45 am ---Shown below are the Nichicon capacitors that have failed, I hope you can see the bulging top.

--- End quote ---
Nichicon had a bad run of HM/HN series capacitors in 2001-2005, if I recall correctly.  If those capacitors are in the date range, it could explain a lot.

However, regardless of brand, some designs like those small form factor PCs running Pentium 4s at 3.0Ghz, will cook any capacitor over time due to excessive heat.

--- End quote ---

Just received the replacement capacitors today. The failed Nichicon's are labelled as HM(M) with codes H0424, H0341. There are also 3 others which are ok but I replaced them on spec as codes are also H0424 and x2 H0341. I'm not an expert on Capacitor date codes but if I get time I'll go to their website and have a look.

Update: the date code is ?yyww so H0424 is 2004 week 24, H0341 is 2003 week 41 and so they fall within the "bad run" years you mentioned.

What_NZ:
Just thought I'd post some pictures of the capacitor replacement. I use a Pace Soldering/ De-soldering Station MBT201, which uses vacuum suction for de-soldering and it is fantastic on heavy supply/ground planes.

So here are some photo's. The final test was checking these power supply lines and a soak test for 3 hours.



Navigation

[0] Message Index

[*] Previous page

There was an error while thanking
Thanking...
Go to full version