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Hello i have Panasonic Receiver model SA-H51 (power: AC 60Hz 120v 170w)
there are two 4700uf 45v capacitors that are not working can i replace them
with any size capacitors...like 10000uf, 55v or 4700uf, 63v
or 6800uf, 50v... or do thay need to stay the same?...thanks for any help!.
Follow Ups:
A change in capacitance from original design depands what the capacitor is performing, of course. RF & IF circuits in a tuner section is a no-no. Coupling caps should not be varied much from original in most cases. Power supply has options and more capacitance is ok. A huge amount more is not necessarily a good option as the peak to average current charging the capacitor(s) is higher. This causes some extra heating of the rectifier diodes and power transformer. I say up to double the original power supply capacitors is ok for tube type gear and 1.33 is ok for solid-state gear. If the tube gear has a tube rectifer feeding a capacitor (capacitor input design) one must follow the tube manufactures data for maximum capacitance value. The difference in-between low voltage and high voltage capacitors is the low voltage capacitors has much lower internal resistance due to the much greater capacitance in the first place. Ultra low internal resistance causes the forementioned heating in the rectifier and power transformer.
As for capacitor voltage, higher is ok, not lower voltage.
My 1.33% higher capacitance post is a loose rule of thumb for an absolute worst case condition. If one wants to get very technical, they can measure the extra heating at the diodes and transformer and that is kind of 'far out' for a person not designing a prototype item for manufactured production. I would use 6800uF at same or higher voltage ratings. Remember this, some electrolytic capacitors are rated -20% to 150% of specified capacitance anyways.
.
--
Mucking around the low-end since 1986.
Hello i have Panasonic Receiver model SA-H51 (power: AC 60Hz 120v 170w)
there are two 4700uf 45v capacitors that are not working can i replace them
with any size capacitors...like 10000uf, 55v or 4700uf, 63v
or 6800uf, 50v... or do thay need to stay the same?...thanks for any help!.
Just out of sheer curiosity: how do you determine that your 4700uF 45V capacitors are not working?
Q.
i was playing some hard bass the next thing i know the speakers stared to make a caking sound, then the music become lower and lower really fast, it happen 9 months before to the left speaker channel, then i just put my 3 speaker on the right channel... on till it happened again now...i tried to replace the speaker but still no music.
Is there a problem with the capacitors? (there where more then 15 year old)
or can it be some different problem?
Thanks for all the help so far.
Higher voltage is fine.
Higher capacitance can get you into trouble, and that depends on the rest of the PS. I would stick with the current capacitance, or slightly higher.
In this situation, more is always better. As long as they are rated for more than 45 volts, go nuts as space allows.
___
Long Live Dr.Gizmo
I would not put caps rated more than say 25% higher voltage than the originals. If the voltage rating is too high the layer of aluminum oxide will not for properly in the plates.
Don't go over board on value either. Higher values will lead to higher raw DC voltages and large inrush currents. Possibly shortening the life of your transformer and other components.
(to answer Quest question)..i was playing some hard bass the next thing i know the speakers stared to make a caking sound, then the music become lower and lower really fast, it happen 9 months before to the left speaker channel, then i just put my 3 speaker on the right channel... on till it happened again now...i tried to replace the speaker but still no music.
Is there a problem with the capacitors? (they where more then 15 year old)
or can it be some different problem?
I was thinking of buying this:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=P6682-ND
but im still not sure that the problem is the capacitors,... i opened my stereo and everything look fine.
Thanks for all the help so far.
Sure looks like a perfect replacement.
Of course, remember they are directional. Note which way the arrow faces in your unit.
It looks easy to test the diodes, with no power; same for the resistors.
Got any other old gear you should replace the electrolitic caps in? I seem to remember the mailing costs stay the same for 1-10 caps of so?
Bob
I don't understand your people.
So, to you I will put and end.
And you'll never hear surf music again!
Good news, I got the new parts form digi-key today, and replaced them with the old ones ..the bad news is it didnt work :(
anybody have an idea why the channels still aren't working?
What have you checked? I saw some diodes right next to where you changed the caps.
Check the incoming voltage to see if it gets to your amplifying components.
Bob
"He (R.M. Nixon) was a foul caricature of himself, a man with no soul, no inner convictions, with the integrity of a hyena, and the style of a poison toad." H. S. Thompson
so..after checking the diodes, and the resistors near the power caps i found out everything was fine, all the diodes have a Current of 3A and Voltage of 200V the resitors are all about 56ohm 1/4.
The transformer looks great (for its age);)
but i just found out if replace the speakers with headphones i can hear the radio but its very low and fuzzy even at max volume. Im thinking its the stereo amplifier chip (stk4152II) i can find it on ebay for less then $10.
Is it the chip?
Thanks for the all help so far.
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