In an 8 track player I am trying to fix, there is a capacitor that says 10/25 on it. When I measured it, my meter said it was 15.4 microfarads. What does this capacitor labeling format mean?

In an 8 track player I am trying to fix, there is a capacitor that says 10/25 on it. When I measured it, my meter said it was 15.4 microfarads. What does this capacitor labeling format mean?

Can you post a photo, please?
If you post your device model, maybe there is some schematic or service manual on internet (i found my vr2030 Video2000 VCR).

Can you post a photo, please?
If you post your device model, maybe there is some schematic or service manual on internet (i found my vr2030 Video2000 VCR).

The 8 track player is a GE SC-2307B. I doubt you will find any information about it because I didn't. I can post a picture of the capacitors themselves too. Just give me a few hours.

I posted the picture here: https://www.lighting-gallery.net/gallery/displayimage.php?album=lastup&cat=12822&pos=0&pid=193341

I would guess 10uF 25V. (25uF is unlikely as it is not a standard size)

Measuring it as 15uF+ is out of spec on the high side which can be explained by eitehr :

You are measuring it at a frequency which is way off the frequency at which its capacity is rated (the effective capacity of capacitors is frequency dependent)

The the interface between electrolyte and electrode (where the oxide is) had dissolved into the electrode and increased the surface area, so really making the higher capacitance, with the side effects of the oxide becoming uneven and unreliable (so odds of higher leakage current, risk of breakdown at lower than rated voltage) and possibly high ESR

In an 8 track player I am trying to fix, there is a capacitor that says 10/25 on it. When I measured it, my meter said it was 15.4 microfarads. What does this capacitor labeling format mean?

It is 10 uF, rated for up to 25 V.
Reading 15 uF means it is dry as heck, so definitely needs replacement. I would guess many other electrolytics there would be in similar bad shape.
And beware: When electrolytics degrade (as the seal is failing and they are drying out), normal capacitance meters wont show nearly any difference, as the first parameter drifting away and making the equipment fail to perform is the ESR (equivalent series resiatnce). The electrolyte solution is there in fact one conductor connecting the dielectric oxide layer (few atoms thick layer on a spongy like aluminum surface). As he electrolyte is drying out, this connection gets first higher and higher resistive, only after it can not reach some of the dielectric surface at all it will show the capacitance drop. But the elevated ESR already means too high impedance for the circuit to work properly.
And most capacitance meters wont show that parameter, you need a dedicated ESR meter for that. So when you see capacitance dropping even slightly below the minimum tolerance, it means the capacitor is completely dead.
Another problem with electrolytics and capacitance meters: Electrolytics tend to develop significant leakage over time (mainly when not used or exposed to mechanical abuse; even dropping he component onto the floor may accelerate this degradation significantly). This leakage then fools the capacitance meters to read higher value than the true capacitance is. So if a capacitor reads too high value (over the upper tolerance), it usually means it is leaky so bad.