Replacing electrolytic capacitors

I had one Elisa viihde base WLAN station + ADSL modem that was unreliable. I had earlier done tear-down of it that I posted to this blog.

Now it is time to try to fix it, because it was making whining noise and was a bit unreliable as WLAN base station.

So it looks like it is time to fix by replacing bad looking electrolytic capacitors because they have limited lifetime and because most common reasons that modern digital electronics devices fail seem to be a bad electrolytic capacitors. You should be able to spot the bad capacitors quite easily from those pictures.

Now they are fixed. The capacitors were replaced with good quality low ESR electrolytic capacitors that have the same capacitance and voltage rating as the original one and also mechanically fit to their place on the circuit board.

Now it works and makes no noise. So the fix seems to work.

Let’s test capacitors with two component testers M168 and M12864 to see in how bad shape those capacitors really were.

Results 470 uF 25 v capacitor was quire bad. The capacitance had dropped to around half of the original value, which is not good. What could be even worse, that the ESR was so high that is is pretty much useless as power supply filtering capacitor. No wonder there were problems.

Then results from 1000 uF 10V capacitor were quite different when measured with two different tester. Based on those it seems that this capacitor was completely useless as power supply filtering capacitor.

Other meter

 

5 Comments

  1. Tomi Engdahl says:

    Six Common Mistakes Made When Recapping Vintage Electronics
    https://www.youtube.com/watch?v=BeDKwi-GJRI

    Short little video on common mistakes seen when recapping (replacing capacitors) vintage electronics. This would include vintage stereos, radios, equipment, CBs, ham radio receivers & transmitters, calculators, computers, you name it.
    Hopefully this will provide you some tips and hints to use when you go to recap your piece of vintage gear.
    Topics include:
    - Mistaking Factory Glue for Leaking Capacitors
    - Factory Boards and Manuals Marked Wrong
    - Capacitors Installed Incorrectly
    - Using Larger Capacitors Than Specified
    - Buying Electrolytic Capacitors off Ebay
    - Replacing Everything at Once

    Reply
  2. Tomi Engdahl says:

    Replacing capacitors in vintage equipment
    https://www.youtube.com/watch?v=a01egKzQCa8

    After 20 years of faithful service, this viewer wants to know if he should replace the capacitors in his equipment and what to look for in new ones. Paul gives us some insights into when it’s a good time to switch and what to replace them with.

    Reply
  3. Tomi Engdahl says:

    Exploding Capacitor With And Without Safety Vent | Experiment
    https://m.youtube.com/watch?v=AmIQ8TM4_u8&feature=youtu.be

    Reply

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