How the Model 10 Differs from the Model 10B
The Model 10 uses toroid cores for the IF stage inductors. Marantz found that these were becoming magnetized on the production line due to the use of Weller soldering equipment (these use a temperature-sensitive magnetic tip to control the applied heat energy.)
When the magnitization occurred, the tuners could not be aligned, and this required a costly re-work of the tuner prior to shipment.
For this reason, you must be very careful if you ever have to do any soldering anywhere near the IF stip of a model 10 tuner. Warn your technician if the unit ever needs service that the IF cores are unusually prone to this problem and a non-magnetic soldering iron should be used at all times.
The 10B contains a design change that uses gapped pot cores, which did not exhibit the magnetization to a level that caused problems.
The dial mechanism was also redesigned for the 10B production run.
The 10's IF strip was aligned cold.
Contributed by Ben Blish
On March 1st, 2000