I'm sorry if this has been posted already; I did a bit of research and haven't found anything related to my issue. I have some vintage Fisher stv-648 3-way speakers that need new caps. (I think). Anyway, I have included some pictures of the existing crossover. I want to rebuild it, but I don't know where to start to find the parts I need. Any suggestions or direction would be greatly appreciated.
Thank you
Thank you
Look at a vendor that has all the crossover parts you need to save on shipping.
Parts Express
Madisound
Dayton Audio
Might as well replace all the capacitors, they are bipolar electrolytic types.
Check resistors with a meter and replace if the value is off more than the marked tolerance..
Don't mess with inductors, they won't go bad except in unusual circumstances.
Parts Express
Madisound
Dayton Audio
Might as well replace all the capacitors, they are bipolar electrolytic types.
Check resistors with a meter and replace if the value is off more than the marked tolerance..
Don't mess with inductors, they won't go bad except in unusual circumstances.
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Here is a direct link to NP electrolytic caps: https://www.parts-express.com/speak...acitors/non-polarized-electrolytic-capacitors
I use P-E because they are close to me, have deep stock, and are usually one day away by UPS. I do not expect to be talked to, I just use the website. If they are out of something I usually find it in stock later. You have to have a debit card in the US. Don't use UPS into Canada, there are customs loan fees.
Your caps are clearly marked with size X.Y mfd 100v which has changed into X.Y uF these days. Don't use less than 100 v caps. You can use more voltage if that is in stock.
Warning to new repair people, solder can splash especially desoldering. Use safety glasses. A suction bulb or solder-wick can make getting the solder off easier. Use rosin core 60/40 or 65/35 tin/lead solder. A 40 watt iron should be fine for these. I use P-E's vari-temp station ~$40.
If you want to measure ESR before you change them, some times you can get an ESR meter from P-E. Other times you have to go to Newark Digikey or Mouser. ESR in spec, they are not bad. Usually dried up e-caps read a little high on the capacitance.
I use P-E because they are close to me, have deep stock, and are usually one day away by UPS. I do not expect to be talked to, I just use the website. If they are out of something I usually find it in stock later. You have to have a debit card in the US. Don't use UPS into Canada, there are customs loan fees.
Your caps are clearly marked with size X.Y mfd 100v which has changed into X.Y uF these days. Don't use less than 100 v caps. You can use more voltage if that is in stock.
Warning to new repair people, solder can splash especially desoldering. Use safety glasses. A suction bulb or solder-wick can make getting the solder off easier. Use rosin core 60/40 or 65/35 tin/lead solder. A 40 watt iron should be fine for these. I use P-E's vari-temp station ~$40.
If you want to measure ESR before you change them, some times you can get an ESR meter from P-E. Other times you have to go to Newark Digikey or Mouser. ESR in spec, they are not bad. Usually dried up e-caps read a little high on the capacitance.
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The resistors aren’t going to go bad. Not without discoloring the board from heat - and by the time that happens the caps are blown to smithereens and you‘ve got confetti inside the cabinet. Or blown drivers, or both. Caps could be bad, no way to tell without measuring. Lacking an ESR meter you could replace one at a time with known good, and if it’s in your face night and day difference (ie the highs suddenly come back from the dead) then the original is bad. They do NOT look suspect to me. When doing a temporary swap you don’t even need an NP. Just an ordinary known good cap, but keep it under 1 volt peak to peak to test. Thats plenty loud enough.
Of course I would change them.
Here would be where I would find caps: https://www.mouser.com/c/?product=Bi-Polar/Non-Polar Electrolytic Capacitors&pg=1
The 1K resistor: https://mou.sr/4794BFB
the 1.5K resistor: https://mou.sr/48mDyro
I change out cement resistors all the time because they are the notorious for the winding to come unglued internally and cause FM distortion in the signal. I don't consider them audio quality but manufacturers use them because they are the cheapest and fail way down the road.
Those are ohm resistors, not k-ohm resistors. K after the ohm symbol indicates 5% tolerance not k ohms.
A “crossover” with just attenuation resistors and high pass caps, on a press fit terminal does not inspire confidence that “better grade” parts would ever be needed. The caps can go bad after 30 years with little or no DC bias, but it’s really an easy check. Either they are still good or they’re not, and probably no need for anything better than fresh NPEs. Resistor upgrades will likely be pointless with the kind of DRIVERS the speaker has in it and the 6dB/octave slopes. With the shallow crossover slope, there is going to be enough LF getting into the mid and tweeter to cause lots of IMD at high power. Enough to swamp out any distortion a resistor (even a poorly made one) might offer.
A “crossover” with just attenuation resistors and high pass caps, on a press fit terminal does not inspire confidence that “better grade” parts would ever be needed. The caps can go bad after 30 years with little or no DC bias, but it’s really an easy check. Either they are still good or they’re not, and probably no need for anything better than fresh NPEs. Resistor upgrades will likely be pointless with the kind of DRIVERS the speaker has in it and the 6dB/octave slopes. With the shallow crossover slope, there is going to be enough LF getting into the mid and tweeter to cause lots of IMD at high power. Enough to swamp out any distortion a resistor (even a poorly made one) might offer.
sorry, didn't read that correctly. I should post after waking up all the way with coffee
then. 1 ohm https://mou.sr/3RT0wRN
and 1.5 ohm https://mou.sr/3TAe1ai