UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Hallicrafters SX-25 Rebuild: New Mains Transformer Questions.

Dave757 · 12th Oct 2020, 10:04 pm

Hi,

The YEL/BLA should not be grounded, - it should not be connected at all.

As this is a directly heated rectifier, the filament is at HT+ potential,
so by grounding the 5V centre tap, you are effectively grounding the HT, -
hence the light show!

It would probably be worth checking that the transformer windings are
OK before rewiring it.

Kind regards
Dave

Sorry, I got called away during my reply, and did not realise I had doubled
with the excellent advice already given
Dave

12th Oct 2020, 10:04 pm	#7
Dave757 Heptode Join Date: Apr 2009 Location: Scratby, Norfolk, UK. Posts: 651	Re: Hallicrafters SX-25 Rebuild: New Mains Transformer Questions. Hi, The YEL/BLA should not be grounded, - it should not be connected at all. As this is a directly heated rectifier, the filament is at HT+ potential, so by grounding the 5V centre tap, you are effectively grounding the HT, - hence the light show! It would probably be worth checking that the transformer windings are OK before rewiring it. Kind regards Dave Sorry, I got called away during my reply, and did not realise I had doubled with the excellent advice already given Dave Last edited by Dave757; 12th Oct 2020 at 10:10 pm.