[ARC5] Undoing a BC-453 conversion

[Ian Wilson]

I recently obtained a BC-453 in quite nice condition, apart from a
couple of modifications:
  - Se rectifier + various electrolytics in dynamotor area (I will just
remove these)
  - 12H6 instead of 12SR7

I had hoped that the 12H6 simply replaced the one diode of the 12SR7
that's used. In that case, I would only have needed to restore the
original connection to the 12SR7 grid. However, the modification appears
more extensive than this.

Was there a popular modification that used both diodes in a 12H6,
perhaps for delayed AGC?

I would like to restore the BFO function (and the original detector, I
guess).

I'm only just starting down the ARC-5 road so would appreciate any
information.
I do have access to typical RX schematics, but haven't located one
specific to the BC-453.

Thanks!

--ian, K3IMW