Something that you notice about the R1155 is the occasional use of what might be termed non-standard value resistors. In the case of the Bias-Board, 3 x 10K resistors were required to make up to 30K and 2 x 100R
resistors to make up to 200R. Don’t be tempted to use preferred values like 33K and
220R. This board is responsible for setting most of the bias voltages and for that
reason, the resistance values are particularly important.
This is the area immediately behind the Jones connectors. The common conductor from
the chassis mounted capacitor was severed and the wiring was somewhat shambolic to
say the least.
This is the area immediately behind the Range Selector. Not too untidy to start with
but definitely looking better after refurbishment.
Finally, this is the are around the Master Switch. This area was host to some of
the most shocking insulation degradation. The two bright yellow wires were part of
my initial attempt to effect a repair without a total strip-down. It is interesting
to note that not all R1155s exhibit this level of degradation. I can only put it
down to a variation in rubber quality at a time when the majority of equipment wiring
was cloth-rubber insulated.