Phonoland

Hi guys. Starting to rebuild my rockola 414 amp.
Question is on the multi-capacitor cans.
I got a kit that comes with terminal strips to help
With the mounting of new caps underneath chassis.
I get that the one point goes to chassis ground.
Then they have 3 and 4 other terminal points.
Are these soldered in series?
I could really use some basic information on this.

Thanks,

George Raven

Raven,
Look at the original "cans"--- they should be marked on the can surface with the specs of each post of the can--it will say something like "300 mfd 450 volts and then have a symbol such as a "square". The next line will have a mark saying 200 mfd 450 volts and a half circle. and so on for each cap located within that can, except the symbol will differ, and usually the last one will have no symbol. Then look at the bottom of the can, next to the posts, and you will see the symbols that correspond with the markings on the can. Sometimes this is on the outside of the post, other times it is on the inside of the post. When you find the half circle, that indicates it's the positive lead of the 200x450 cap. the square indicates 200mfdx450v , and so on. The whole outside of the can, and any twist-locks" holdng the can to the chassis are all common "Ground" ( or "Earth"). Ron Rich

Would I connect the positives to their corresponding posts,
And the negatives to the terminals on the strip that came in
The kit? And then the strip to chassis. How to disengage
The original can? Forgive the rookie questions, first amp
Project.


Thanks again for info
Raven

Raven,
Absolutely, connect the new pos. terminals to the WIRES that you must remove from the original post, and connect the (-) to a GOOD ground (earth) connection, on or near the original connection. I leave the original "cans" standing, just for appearance sake. If you can fit a terminal strip in the amp, you may do so, just for "neatness", but it is not required. I mark each "replacement" (can) cap, showing the symbol, or the "C" number as shown on the schematic, with a "Sharpie", as I replace it, so that the "next guy" can understand what I did. If required, I also glue the caps to the chassis. Ron Rich

That's the exact info I needed!
Many thanks Ron.
I'll let ya know how it turns out.

George Raven

Some values of the twist prong can style electrolytic capacitors (also known as "FP" types) are available brand new from Antique Electronic Supply in Tempe, Arizona.

Their website is www.tubesandmore.com

Personally, I like to use new twist prong can caps, if i can get the correct values. Second choice is to hacksaw open the old cans and "restuff" them with new caps.

Ken,
Guess am lazy--I did not like replacing "twist-locks" when they we readily available ! I "had to" when I worked for a "boss"--but since then, I can count the number of them I have done it on one FINGER "Hack-saw", and "re-stuff"---don't need any fingers to count the number of times I have done that--besides, most "customers" don't want to pay for the additional time it would take ! Ron Rich

There are some electronics out there where there is literally no room under the chassis to mount seperate electrolytics. The old Bell & Howell 16mm projector amplifiers come to mind. I've done several of those and they are so crowded that you cannot put any seperate electrolytics under the chassis. You have to either replace the can with a new one or hacksaw it open and restuff it. The antique radio guys are in the same boat too.

Granted, if there's room on the item being repaired for under-the-chassis seperate electrolytics to be installed then go for it. I've done that too.

Ken,
Well, I guess that's why I don't "do" B&H Projectors, or old radio's !! Ron Rich

There's just one positive terminal that comes off
One of the cans. This had one wire on it that goes directly
To the negative twist lock on one of the other cans.
How to wre in the new cap?

This is I believe a doubler. I'm stuck!

Thanks George raven

George,
If I understand your question correctly---
If there is only one "positive" and the other wire goes to the twist lock, install the new cap the same way. If possible, you should use the twist lock can for the negative wire on the new cap, and remove the wire connected to the old pos., and connect it to the new cap (+)---Ron Rich

There was just the one wire. It came off positive post, and went directly
To the negative twist lock on the other "doubler" can.
That's the thing if ya snip the wire at the positive terminal, the end of that wire is where
You solder the positive on the new cap, correct?
Now, that wire just goes over to the twist lock..
It would be like your cap was just in a loop. I'm thinking ground it to the can it came from?


Thank raven