Hello.

first of all the question:
Can I use polarized capacitors in a location where they shouldn't be polarized? And if so, does it matter how they are connected ?

I've been in the process of restoring a jukebox. Recently I figured out that the junction box, which holds quite a bit of resistors fuses and capacitors, has three large capacitors from the 60-ies... Needless to say they have to be replaced with more recent ones.
They are:
50 WVDC 100 MFD wurlitzer part no. 73862
View attachment 154640
50 VDC 500 MFD wurlitzer part no. 71816
View attachment 154642
400 VDC 0.5 MFD wurlitzer part no. 73099-140
View attachment 154641

This however has prooven to be quite the challenge.

I have bought the replacement capacitors which are on their way, however I overlooked an important bit...
According to the schematic drawing (see attachment) only one capacitor has to be polarized, the other two simply have the icon for capacitor with their respective values.

Those two capacitors that are currently inside the jukebox are polarized, and I bought the replacements based upon their values.

Any thoughts are welcome
MOD: lightened up your circuit image.

Aluminium will tolerate small reverse excursions, but not a standing reversal - reversing the voltage on tantalum is pretty much instant death.

Multilayer ceramic chip capacitors are very small with impressive capacitance values - I've seen up to 180uF in a brochure.

Some people use aluminium pairs back to back. AFAICR: it 1/2 capacitance just like any series pair of identical capacitance, unless you fit each cap with a parallel reverse blocking diode.

There are also NP aluminium electrolytics - probably some significance to the fact not many people bother using them.

 

If a capacitor is marked xxx VDC and has a + sign at one end, it is clearly a polar capacitor. I've never seen a non-polar electrolytic (and at 500 µF 50 V, it can't be anything else in that physical size) that wasn't conspicuously marked "non-polar."

At 0.5 µF & 400 V there are lots of choices in non-polar film caps, though finding axial leads may be a problem. The band on the original probably marks the outer foil. Such caps were made with two long strips of foil with the insulator, probably paper, between, rolled up. The outer foil was usually marked because in audio circuits where you connected the outer foil could impact noise pickup (e.g. if one end wer grounded, it would be the outer foil).

 

Thanks, again !

there seems to be quite an array of choice considering the 10 ohm resistor...

The thing could be like this -- The values of watts was not enough when the big current flows through it, day by day, and then the resistor unable to withstand the heat any more, so it was broken.

Maybe you can choose a resistor with 2 ~ 5 watts.

there seems to be quite an array of choice considering the 10 ohm resistor...
Would I be correct with either one of these below ? The voltage would be 50 VDC judging from the cap, but these are quite over that, 400v and 500V. But I guess it's the watts and the resistance itself that matters most.

I take it these can be inserted either way since I seem to recall a resistor has no polarity, right ?
The first is a (1) watt the second two (2) watt, I'd order them both and see how things go from there.

https://eu.mouser.com/ProductDetail...GAEpiMZZMu61qfTUdNhG/4LCfMV2gNvEGgIC3%2b7R5A=
https://eu.mouser.com/ProductDetail...GAEpiMZZMu61qfTUdNhG1OBxA5drK7V%2bWzCK5TjrG8=

 

The original resistor was almost certainly a "carbon composition" type. If you look at the broken end and it appears to be a thin-walled tube with a "filling" of black material, it would confirm this. Most ordinary carbon comp resistors were rated at 1/2 watt and 10% or even 20% tolerance was common. Carbon composition resistors have gone from being very common in the past to very rarely used now.

Carbon comp resistors are able to withstand quite high transient power. Carbon film resistors aren't. Because the resistor is in series with a capacitor it might see fairly high peak power, even if the average power was well under the rating. In film types, "metal oxide film" generally has the best transient power handling capability. A wirewound resistor has very high transient power capability and one rated at 1 watt would be more than adequate (e.g. CW00110R00JE70 from Vishay/Dale is reasonably cheap).

The voltage rating won't be an issue. It is, in part, a rating for the insulating materials used.

 

Would I be correct with either one of these below ? The voltage would be 50 VDC judging from the cap, but these are quite over that, 400v and 500V. But I guess it's the watts and the resistance itself that matters most.

The capacitor is care about the capacitance(and more as ESR) and rating voltage for different purpose as frequency, noise, filter and voltage in the circuit, the resistor is care about the resistance and rating wattage for different current, voltage and power dissipation.

I take it these can be inserted either way since I seem to recall a resistor has no polarity, right ?

Yes.

And choose the 2W is better.