D G

For parts units I would look at the following models:

2245A
2246
2246A
2252
TAS455
TAS465
TAS475

Before you buy a parts unit, confirm the model has the part...  You can verify using the model's service manual.  My list above could be wrong, but that is what I found.  It might also be worth, if you can, pulling the serial number of the parts unit and checking against serial breaks in the Replacement Parts section of the manual.  You might also want to check with the VintageTek museum...  They may have the part, or a parts unit available.

Hope that helps.