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 Help needed for newbie with Philips RF780 RadioGram Repair
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 Return to top of page · Post #: 16 · Written at 4:48:43 PM on 24 September 2020.
Ian Robertson's Gravatar
 Ian Robertson
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2476

The reason the dim bulb did not light is the ELCB tripped first.

In any case that circuit draws very little power so it's unlikely to light the bulb even when working properly.

There are some faults that can occur in such an amplifier that WILL light the bulb, to keep the smoke in.
 
 Return to top of page · Post #: 17 · Written at 5:40:22 PM on 24 September 2020.
Fred Lever's Gravatar
 Fred Lever
 Location: Toongabbie, NSW
 Member since 19 November 2015
 Member #: 1828
 Postcount: 1313

In general the service bench should have its own Core balance / Earth leakage trip switch.
Then the outlets running on that circuit will have some personal protection.
After that you can have your metering, dim bulbs, variacs isolation trannies and so on.
Thats how my workshop is wired and the 20ma core balance has saved my bacon a few times.
You will get nuisance tripping from junk S/M supplies and some stuff.
Better a nuisance trip than a trip to the mortuary.
I have a circuit upstream to the elcb/cb that has a roof lamp if the drop out is in the night and also supplies the battery back up stuff you never want to drop out.
Fred..
 
 Return to top of page · Post #: 18 · Written at 6:53:45 PM on 24 September 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6761

Better a nuisance trip than a trip to the mortuary.

That's for sure!
 
 Return to top of page · Post #: 19 · Written at 1:04:12 AM on 25 September 2020.
NewVista's avatar
 NewVista
 Location: Silver City WI, US
 Member since 10 May 2013
 Member #: 1340
 Postcount: 977

Looking at schematic...
The first Amp stage employs a bootstrap circuit (cool!) to raise impedance to a level suitable for ceramic cartridge loading...
 
 Return to top of page · Post #: 20 · Written at 11:15:39 AM on 26 September 2020.
Irext's avatar
 Irext
 Location: Werribee South, VIC
 Member since 30 September 2016
 Member #: 1981
 Postcount: 485

My work bench has a double output GPO with an inbuilt 10 mA ELCB which then loops to other GPO's in the garage.
It's far better and safer to trip that one rather than the 30 mA one in the main switch board which plunges the whole house into darkness.
 
 Return to top of page · Post #: 21 · Written at 12:46:17 PM on 26 September 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6761

My workbench has its own RCBO-protected circuit.
 
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