Riz, as I expected, a lot of people I asked said ” 😯 😯 😯 ” about the idea. Still, there’s a guy I know called Rich M and he’s given me some useful information.

The basic idea could be better than a Variac for old capacitors, because the Variac doesn’t alter the AC much. However, he thinks that lightbulbs don’t offer anywhere like enough resistance. A 1Mohm resistor in series is a better bet, and still cheap.

As Rich pointed out to me, it may not be necessary to have lots of bulbs, or lots of resistors. Just as a 25W bulb can be replaced with a 40W, then 60W, then 100W (this is similar to removing one bulb at a time), so a 1M resistor could be replaced by a 500k, then 250k and so on. Even this may be unnecessary; the resistor simply allows the cap to charge up at its own rate, decreasing the initial ‘shock’.

As soon as I get more info, I’ll pass it on.

Riz, my mistake 😳 . I didn’t read properly your crucial phrase:
[quote]he suggested me to put some bulbs before the organ’s power cable, linked in series[/quote]

I’m sorry – my previous post didn’t make much sense. I must tell you that I don’t fully understand how to do this properly. I am not qualified in electronics and I’ve never heard of this procedure. I only pass on what I have understood from techs with better knowledge. If you would like, I can ask for opinions and explanation from friends with theory and experience. Let me know if you would like this information. Myself, I would not attempt the task but perhaps it will be more straightforward if explained properly by the real solder-sniffers 🙂 .

Hello and welcome back, Riz. Sorry for the delay in replying – things have been happening over here.

OK, I understand what your tech’s saying. If capacitors have been left “on the shelf” for a while, they appreciate being brought up slowly. The lightbulbs seem an oddly “homegrown” way of doing it. The Variac is more straightforward. Anyhow, to wire up four lightbulbs (or anything else) in series, it goes like this:

The power supply +ve is wired to bulb #1’s +ve. Bulb #1’s -ve is wired to bulb #2’s +ve. Bulb #2’s -ve is wired to bulb #3’s +ve and so on, until bulb #4’s -ve is wired to the power supply’s -ve. That is serial.

For parallel, the PSU +ve is wired to bulb #1’s +ve, which is then daisy chained to the +ve of the other three bulbs. Bulb #1’s -ve is daisy chained to all the other bulb’s -ves and the -ve of bulb #4 is wired to the PSU -ve.

To tell the difference, take out a bulb. In parallel, the remaining three bulbs will stil light up. In series, the whole lot go dead (the circuit is broken) until the +ve to -ve loop to the PSU is re-established.