1972 Sears Portable Set... Can't read this Sanyo Capacitor?

[Magnavox300]

Just finished recapping a little Sears 13" portable tube set from about 1972...
The 4.7uf electrolytic caps I just replaced are smoking, but the old 4.7 Sanyo never smoked... Am I reading the old cap correctly?
Numbers 1&2 are 4.7UF each, and number 3 is ground? Thanks for any help...

[damen]

Terminal number 3 says NC (no connection). Since it says "AC", terminals 1 and 2 are the active connections. Apparently, non-polarized.

[Magnavox300]

Originally Posted by damen

Terminal number 3 says NC (no connection). Since it says "AC", terminals 1 and 2 are the active connections. Apparently, non-polarized.

Thanks... so if it is non polarized, is it safe to put in a nichicon 4.7 160v electrolytic cap?

[Electronic M]

Originally Posted by Magnavox300

Thanks... so if it is non polarized, is it safe to put in a nichicon 4.7 160v electrolytic cap?

If that 160V rating is DC and there is a marked negative terminal then, NO. Most electrolytic caps are polarized meaning the voltage across them must be of the marked polarity.

Non-polarized lytics are more expensive so they aren't designed into something unless absolutely necessary.

There are 3 possible replacement options: non-polarized film cap 250VAC rated with good ripple current (probably the most expensive, probably the longest lasting), AC motor run cap (probably physically bigger than the original and possibly tricky to find space for), find a non-polarized lytic if that value is still made, make a non-polarized lytic out of 2 polarized 160V or higher lytics of double capacitance (10uF) connected in anti-series.
By anti-series I mean take the 2 caps, connect the negatives of both together, tape over the connection so nothing else can connect to it, then the 2 positives connect to the circuit and behave as a single 5uF 160V non-polar lytic.

[Magnavox300]

Originally Posted by Electronic M

If that 160V rating is DC and there is a marked negative terminal then, NO. Most electrolytic caps are polarized meaning the voltage across them must be of the marked polarity.

Non-polarized lytics are more expensive so they aren't designed into something unless absolutely necessary.

There are 3 possible replacement options: non-polarized film cap 250VAC rated with good ripple current (probably the most expensive, probably the longest lasting), AC motor run cap (probably physically bigger than the original and possibly tricky to find space for), find a non-polarized lytic if that value is still made, make a non-polarized lytic out of 2 polarized 160V or higher lytics of double capacitance (10uF) connected in anti-series.
By anti-series I mean take the 2 caps, connect the negatives of both together, tape over the connection so nothing else can connect to it, then the 2 positives connect to the circuit and behave as a single 5uF 160V non-polar lytic.

Wow, never knew you could do that with 2 electrolytics, so that's what i'll do! Thanks so much, great info!