UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

ricard · 17th Feb 2020, 8:58 am

Especially in picture #2 above, it looks like there is a bit of shiny metal where the gap would be, looking rather like the surrounding brass. Is this in fact a spacer that's part of the internal construction of the heads?

The thing that looks strange with these TK819 heads is that, across the face of the head, the brass gives way to what looks like something red, i.e. the potting compound, followed by a strip of metal (?), followed by more red, followed by the brass. There's no remnants of the pole pieces whatsoever.

Given the uniformity of the center piece, I would second Boulevardier's opinion that someone has attempted to re-lap the heads without understanding what they were driving for. The fact that the head in #1 shows virtually no sign of wear substantiates this. On the other hand, the head in #2 does show significant signs of wear despite having the same overall appearance, perhaps it was re-lapped first, and the machine continued to be used with head #1 unchanged?

17th Feb 2020, 8:58 am	#168
ricard Octode Join Date: Mar 2006 Location: Lund, Sweden Posts: 1,632	Re: Grundig TK 819 Any Useful Info Especially in picture #2 above, it looks like there is a bit of shiny metal where the gap would be, looking rather like the surrounding brass. Is this in fact a spacer that's part of the internal construction of the heads? The thing that looks strange with these TK819 heads is that, across the face of the head, the brass gives way to what looks like something red, i.e. the potting compound, followed by a strip of metal (?), followed by more red, followed by the brass. There's no remnants of the pole pieces whatsoever. Given the uniformity of the center piece, I would second Boulevardier's opinion that someone has attempted to re-lap the heads without understanding what they were driving for. The fact that the head in #1 shows virtually no sign of wear substantiates this. On the other hand, the head in #2 does show significant signs of wear despite having the same overall appearance, perhaps it was re-lapped first, and the machine continued to be used with head #1 unchanged?