Capacitor balancing resistors.

We all start somewhere
User avatar
Nick
Site Admin
Posts: 15706
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#31 Re: Capacitor balancing resistors.

Post by Nick »

The leakage current is at full rated voltage, it will be less at lower voltage. Draw out what you have and mark the capacitor polarity on it.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#32 Re: Capacitor balancing resistors.

Post by Mike H »

Check your wiring. Summink's not right somewhere.

It's also possible one of the caps could be a short-circuit.
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#33 Re: Capacitor balancing resistors.

Post by pre65 »

Nick wrote: Fri Feb 24, 2017 10:36 pm The leakage current is at full rated voltage, it will be less at lower voltage. Draw out what you have and mark the capacitor polarity on it.
Will do. Will probably be tomorrow (Saturday) now.

I tried one pair of caps with two 270R resistors, and same thing, no centre volts, or only in millivolts.
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#34 Re: Capacitor balancing resistors.

Post by pre65 »

This should be it.

Image
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#35 Re: Capacitor balancing resistors.

Post by Mike H »

Can you try one pair at a time, by disconnecting the other pair, and measure the junction Voltage.
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#36 Re: Capacitor balancing resistors.

Post by pre65 »

Mike H wrote: Fri Feb 24, 2017 11:41 pm Can you try one pair at a time, by disconnecting the other pair, and measure the junction Voltage.
I tried one pair earlier and with 1K 7W resistors the junction voltage was in milivolts. (forget the actual reading).

Thing is, on the first test both pairs were behaving the same way. :?

I have got 4 more of those caps (for the other monoblock) so I could try those.
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#37 Re: Capacitor balancing resistors.

Post by Mike H »

Bizarre.

Which side of the junction is the 'short', between ground and the mid point, or positive supply and mid point?

And whichever way it is, is it the same for each pair.
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
User avatar
Nick
Site Admin
Posts: 15706
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#38 Re: Capacitor balancing resistors.

Post by Nick »

Is the stud isolated? Its normally connected to the -ve terminal of the cap.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#39 Re: Capacitor balancing resistors.

Post by pre65 »

Nick wrote: Fri Feb 24, 2017 11:56 pm Is the stud isolated? Its normally connected to the -ve terminal of the cap.
Aha !!

Stud to pos approx 18K ohms.

Stud to neg zero ohms.

Bugger. :oops: :oops:

At least I now know what the problem is. Thanks Nick & Mike. :)
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#40 Re: Capacitor balancing resistors.

Post by Mike H »

A-HA!!

:D

Well there ya go.


Did I tell you the story of when I was soldering up a power supply using one of those old 2-in-1 can caps with 3 tags, of which one is the common negative. The can is also earthed through chassis so for some reason I was looking at the 3 tags as the anodes of 3 separate caps. So I joined 2 together to act as the reservoir. Solid-state bridge so when turned on, mains transformer started smoking. Cue mucho expletives when I realised what I'd done. Never did find an exact replacement for that transformer either.
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
User avatar
IslandPink
Amstrad Tower of Power
Posts: 10041
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

#41 Re: Capacitor balancing resistors.

Post by IslandPink »

All's well that ends well ....
"Once you find out ... the Circumstances ; then you can go out"
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#42 Re: Capacitor balancing resistors.

Post by pre65 »

IslandPink wrote: Sat Feb 25, 2017 11:41 am All's well that ends well ....
Indeed Mark. :)

Just need to solve the problem now. Initial thoughts are M12 sleeve nut and a nylon top hat washer.

I could make them, but I'm looking on Ebay to see whats available.
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
andrew Ivimey
Social Sevices have been notified
Posts: 8307
Joined: Mon Jun 11, 2007 8:33 am
Location: Bedford

#43 Re: Capacitor balancing resistors.

Post by andrew Ivimey »

It ain't over yet Mark!

Onwards! or, as a very strange man from Bradford I once met would say in such a situation, 'Get Forrad! '

-not relevant but in travels nearly 40 years ago I had said ta ta to Steve in Athens. He was flying home and I was off to find a particular clinic where I could sell some blood so I too could...well, catch The Magic Bus home...which I did. About six months later Ann & I ( from kibbutz days) had just got up to leave the Leicester Square Odeon, where we'd much enjoyed Gandhi, Steve said Wotcher mate! He'd been sitting behind us.

What are the chances of that!? Small World eh.

Get Forra'd !
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#44 Re: Capacitor balancing resistors.

Post by Mike H »

Drill holes oversize, two plastic washers and a bit of a plastic sleeve kind of thing.
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#45 Re: Capacitor balancing resistors.

Post by Mike H »

Oh he's already doing it. :D
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
Post Reply