WEM Custom 15

[Kalee20]

The last one (circular) is a lit smaller capacitance than the others - may not be quite so effective at suppressing the clicks.

However, it is a ceramic type - and I have never had one of these fail.

Has anyone got any anecdotal evidence to support the ceramic being greater reliability? (Slight down side is that variation with temperature is generally greater: the suppression capacitors use medium-K dielectrics to keep size down at the voltage ratings needed).

[Bushbaby]

Just to double, double check (being very safety conscious) if I take the 1st cap (grey) I can wire this across live to neutral (brown to blue or in this case red to black). It does show the extent of my electrical knowledge - I really do want to attend some courses when I finally retire (might be 2020)

Thanks again to all for you help.

Best Regards

Rob

[ppppenguin]

Any of those caps can be safely wired between live and neutral. Only the last, the ceramic with Class Y marking, may be wired between live (or neutral) and earth.

[Bushbaby]

H E L P!!
I have wired up the amp with a replacement transformer BUT its blowing the mains plug 3amp fuse each time I try it. This is going through an isolation transformer in the first instance which is also on an rcd. To start with I am just checking that I have main voltage to the amp main switch (no switched on) with no valves in place. It must be something I have done wrong with the switch. The primaries on the transformer are 0v Blue, 230v Pink, 240v Brown and 250v Grey. Its connected as 240v at present (using the screw in amp connector)

At present I cant see what I have wired incorrectly but its obviously staring me in the face - can anyone offer any help please?

Many thanks

Rob

                   

[Bushbaby]

some are the pics are bad and I will update shortly

[Bushbaby]

some better pics.
Checking the resistance across the live/neutral of the plug shows OL.

               

[valvekits]

Assumptions- no valves fitted including rectifier and yellow wire is the fused live, which then comes off the on/off switch as a red wire and goes to transformer tapping selector. Here  you have got the middle brown wire selected which is for 240V.
On my monitor, I am seeing two brown wires which suggests something does not agree with your assumption that the brown wire is 240V.
What happens if you just select the grey wire?

Eddie

[Bushbaby]

Its the picture - the colours are as stated: pink 230v/Brown240v/Grey250v/Blue 0V

I do have a feeling I have made a big error in the switch/lamp wiring. The first pic shows the original power transformer connections (green 220v/Blue 230v/Brown 240v/Orange 0V). The problem for me is I cannot determine where the orange cable from the -ive side of the switch goes to link up with the orange cable from the primary? I wish I had taken a better pic of the original other than the last one I have attached. I'm assuming that the orange cable in the original pic certainly does not go to the voltage selector (instant short circuit).

Can anyone help as I am stumped now.

Best Regards

Rob






               

[valvekits]

If it were me starting from the position you are in, I would disconnect everything.
Next I would measure on ohms between grey and blue which I would suggest is the safest place to put 240V. But before I did that I would measure between the grey and secondaries to make sure there are no readings.
If I was happy with the cold checks I would just stuff 240V straight out of the mains onto the primary (no on off switch) and measure the secondary voltages. I wouldn’t bother with the isolation transformer for this, of course you can still use your protective mains device but simple is best and you shouldn’t be thinking the isolation transformer is going to keep you safe as only common sense will do that. In fact this is what I would have done when the new transformer arrived.

If I got that far and the voltages check out without tripping anything, I would check that what I think are the poles of the mains switch, really are the poles of the switch and I’m not switching live to neutral which would guarantee to take your fuses out.

Also, I don’t understand why the live and neutral are fused - I could give you one good reason for NOT doing that, but I couldn’t give you a reason for doing it.

Eddie

[ppppenguin]

Sound advice from Eddie. In case there's any perceived ambiguity when he says "no readings" he means open circuit or infinite resistance.

Incidentally, when making resistance measurments, saying "OL" is pretty meaningless. Different meters display open circuit or infinite resistance in different ways and I'm guessing yours says OL. My Fluke 87 also says OL on the display when reading an open circuit. Just say "open circuit". It's not really an overload condition and it's not entirely helpful that DMMs display it as such.