my SR-JV80-04 Vintage Synth board has no capacitor, safe? Issues?

[Sir_Ricardo]

Greetings -

I just got this off eBay. To my amazement, it does not have a capacitor. Instead, where the cap should be is a burn mark.

However, it seems to work fine.

What do you guys make of this? Safe? Issues?

thanks

Richard

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[RolandoKix]

First, I am not a technician, and my input here is just my initial reaction. As far as I know, a missing component would cause the circuit to break, and no longer work. Maybe the capacitor works in addition to a connection that underlies it - I have no idea. It looks like that capacitor exploded and was removed.

I do not think it would be safe/reliable to use long-term. There are repair videos online by pros where a new capacitor is soldered in. Nobody says "you don't even need this thing."

[Sir_Ricardo]

Thanks for the reply. The board somehow works fine, it's been in use now consistently ever since I posted this thread. How/why it can work perfectly without its capacitor is beyond me, but it does work, just fine.

[Foksadure]

The capacitor purpose is to filter or smooth the current applied to the chips.
There's a reason this one has blown up.

https://gearspace.com/board/electronic- ... -card.html

Typically on boards like this there's a larger cap (C5) where the power rails enter the board, then smaller caps near each chip.

Which mean you're stressing the other components on the board, which may lead to future problems just because of a missing $0.50 cap.

I wouldn't use the card without putting an over-specced 100uF 16v replacement capacitor first.

The eBay seller should be notified and evaluated accordingly.