In a previous video, I presented the Design and Build of the "deluxe" Dim Bulb Limiter / Tester with integrated Isolation Transformer, that reduces the risk of shock in "hot chassis" equipment, and could also save your test equipment.
The link to the original video is:
   • DIY Test Gear: Dim Bulb Limiter / Tes...  

Since then it has been in constant use, and as is typical, I have found reasons to improve it.

The first one is to allow for more current than the isolation transformer can handle, without dropping the voltage. This is especially useful when you have determined that there is no short, and want to do a bypass. With the 1.5 Amp maximum capacity of the transformer, the output voltage starts to lag a bit after about 1 Amp.

The second reason is too provide the limiting function, while being connected to the mains with the mains earth connection in place. This is especially important for the final testing, where some shorts to earth will only show if you have the device earthed.

Anyway, I hope this proves helpful, and once again, I must warn you to be very careful as the voltages involved can be lethal.




See a series of 'Tube Radio Restoration Building Blocks' videos on detailed steps in the restoration process:
   • How to safely check the Power Transfo...  


See also playlists on some other completed restoration projects.

PHILIPS BX750A:
   • Philips BX750A tube radio restoration...  

TELEFUNKEN OPUS 2114:
   • Telefunken Opus 2114 stereo tube radi...  

SABA UW175Z 3D:
   • Saba UW 175Z 3D tube radio restorati...  

GRUNDIG 1070:
   • Grundig 1070 tube radio restoration ...  

SCHAUBLORENZ GOLDY 58 type 3020:
   • SchaubLorenz Goldy 58 type 3020 tube...  

BUSH VHF64:
   • Bush VHF64 tube radio restoration  P...  

GRUNDIG 3060A:
   • Grundig 3060a tube radio restoration ...  

TELEFUNKEN OPERETTE 8:
   • Telefunken Operette 8 tube radio rest...  

GRAETZ SUPER 171W:
   • Graetz Super 171W tube radio restorat...  

LOEWEOPTA MAGNET 3737W:
   • LoeweOpta Magnet 3737W tube radio re...  

BRAUN ATELIER 3:
   • Braun Atelier 3  

LOEWEOPTA TRUXA STEREO 4741W:
   • LoeweOpta Truxa Stereo 4741W  

GRAETZ COMEDIA 616:
   • Graetz Comedia 616 tube radio restora...  

SABA FREIBURG W2:
   • Saba Freiburg W2 (WII) restoration  

GRAETZ MUSICA 4R417:
   • Graetz Musica 4R417 restoration  


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