Author Topic: Recapping 20-year old BMW car audio amplifier  (Read 465 times)

0 Members and 1 Guest are viewing this topic.

Offline Fried ChickenTopic starter

  • Regular Contributor
  • *
  • Posts: 160
  • Country: us
Recapping 20-year old BMW car audio amplifier
« on: September 02, 2024, 03:00:10 pm »
I'm not sure if it needs a recap, but I have a cheap parts unit, all the tools, and the capacitors themselves are cheap.
The unit is from 2003 so about 20 years old, made by Harman Becker according to the PCB, Harman Kardon according to BMW's marketing.
The issue is I can't find the capacitors.
They're all rated for 105°C.

I'm seeing "SXE", "LXY", one Rubycon, and a whole bunch of "KME" which I believe is United Chemi-Con but no longer manufactured.

It's one of the most beautiful PCBs I've ever seen.  The glue has held up beautifully, the case is some like forged powder coated steel.  It's so good.  So so good.

Anyway, I have two approaches I feel I can take.  1. find a cross referenced matching capacitor (I'm not sure how).  2. Find capacitors that meet the known spec with everything turned up to 11 (low leakage, low ESR, highest life rating, most expensive, etc.)

Help with this would be appreciated!
Google is spyware
 

Online jpanhalt

  • Super Contributor
  • ***
  • Posts: 3998
  • Country: us
Re: Recapping 20-year old BMW car audio amplifier
« Reply #1 on: September 02, 2024, 03:53:59 pm »
Does it work?  Why "recap," if it does?   

 
The following users thanked this post: Manolo Mos

Online wasedadoc

  • Super Contributor
  • ***
  • Posts: 1686
  • Country: gb
Re: Recapping 20-year old BMW car audio amplifier
« Reply #2 on: September 02, 2024, 04:17:38 pm »
While it is true that capacitors handling high ripple current do age, get tired, dry out etc I don't find that a general "replace all electrolytics" is usually warranted. The smaller ones on that board will be audio coupling or supply decoupling. I have audio gear much older than 20 working fine with original through hole electrolytics still in place. Those little round can SMD electrolytics are a different story.

Though some scoff, those $10 transistor testers are amply good enough to (out of circuit) test if loss of capacitance or increased ESR warrants a replacement.

If you do decide to replace you do not need make for make, type number for type number.

As an aside KME can mean Kyushu Matsushita Electric, part of the group now better known for the Panasonìc brand name.
« Last Edit: September 02, 2024, 04:26:28 pm by wasedadoc »
 

Online Xena E

  • Frequent Contributor
  • **
  • Posts: 681
  • Country: gb
Re: Recapping 20-year old BMW car audio amplifier
« Reply #3 on: September 02, 2024, 06:28:51 pm »
Unnecessary blanket re-caps are the number one reason for the trashing of vintage electronic gear.

Yes, electrolytics can and do fail, but on the amount of hours that your HK is likely to have run, it's unlikely to have worn them out.

How do you know the new ones will be any better?

X
 
The following users thanked this post: David_AVD

Offline Jeff eelcr

  • Frequent Contributor
  • **
  • Posts: 308
  • Country: us
Re: Recapping 20-year old BMW car audio amplifier
« Reply #4 on: September 02, 2024, 10:23:49 pm »
If the caps do not show signs of physical leakage and no snap, crackel, or pops and the amp has good audio then for now, they work ok.
It all comes down to time and tempature for failure, garage kept or sits outside sun/shade, how long etc.
Size of caps can make a difference, larger 7mm and up outlast 5mm but different caps fail in different ways.
Jeff
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf