0
\$\begingroup\$

I have outdoor speaker that has leaked over the years and now the passive crossover inside has become corroded and the tweeters no longer work. This is a dual voice coil speaker, so it takes both channels.

Image of PCB

I'd like to replace the non-working components on the board but I need help identifying them so I can find suitable replacements.

The path to the 8" woofer passed through the large coil and that still works, so I will leave that be.

Following the traces on the PCB, the path to the tweeters is as follows:

  1. Yellow capacitor
  2. White resistor
  3. Fuse

From my searches this is what I think these components are:

Yellow circle: Polypropylene Film Capacitors, 2.2uF J 100V Axial

White square: Ceramic capacitor 5w 4ohms and the J is 5% tolerance

Flat capacitor looking thing: Seems to be a resettable fuse, JK60 065

Looking for these products on Mouser, I can't seem to find the filters that produce the right combination of requirements.

Have I identified these correctly, is there something commonly available that can be swapped in?

\$\endgroup\$
  • 2
    \$\begingroup\$ 5 W, 4 ohms is a resistor, wirewound. That's why you can't find it under capacitors. \$\endgroup\$ – Transistor Mar 3 at 22:26
6
\$\begingroup\$

Despite dirt and surface corrosion, most of those parts may still be working. Test each to see if it needs replacement.

  • Start with gentle cleaning with detergent and toothbrush; let dry.
  • The culprit is likely the component with broken lead at the bottom -- you say it's a resettable fuse.
  • The two white rectangular objects are ceramic resistors, and a multimeter should show ~4 ohms each, within ~20% is acceptable.
  • The two coils are inductors and should be less than an ohm or two.
  • Some multimeters measure capacitance; the two yellow capacitors should be 2.2 mfd (µF), again ±20%.

Also check traces on the PCB for any breaks, which, for audio frequencies, can easily be bridged with a piece of wire.

\$\endgroup\$
  • \$\begingroup\$ Thanks for the info. I do think that most of these components probably still work, but the leads all look fairly corroded and I didn't want to go through the effort of cleaning it up, replacing the broken part and then have something fail soon after. Opening and resealing the speaker is a big effort, it has got mounds of silicone keeping it water tight. \$\endgroup\$ – Gary Bak Mar 4 at 0:40
  • \$\begingroup\$ Is a lower tolerance okay? I found replacements at 5%, I'm guessing that would be fine for this application. \$\endgroup\$ – Gary Bak Mar 4 at 1:17
  • \$\begingroup\$ Lower tolerance is better, though sometimes more expensive. 5% is good. \$\endgroup\$ – DrMoishe Pippik Mar 4 at 1:43
  • \$\begingroup\$ Plastic film caps are usually 10 % so 5% is excellent ( sorted or binned) The J is what 5%? \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Mar 4 at 16:46
1
\$\begingroup\$

Closest match for the broken PTC 650mA, 60V is

60V 650 mA holding current 480 mOhms

This is intended to heat up and limit the Tweeter current, if it sustains twice the holding current so the tweeter won't burn up.

I^2*R= 1.3^2 * 8= ~ 14 Watts RMS threshold)

enter image description here

This is my schematic, using your Cap value to compute L for 8 Ohms (close not exact)

I learned a new filter name today! It is also known as a Butterworth squared filter.
( It's costs about $20 online but can be made for ~$5)

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.