HP3400A thermocouple replacement?

[worsthorse]

I have a 3400A that the previous owner said, "just stopped working".  When I got it apart I found a broken power socket and damaged AC wiring harness. Found a replacement power socket and repaired the wiring harness (thanks to @factory for the photos!), applied power and nothing exploded. Proper DC voltages in the right places. That's the good news.

The bad news is the thermocouple is bad. When I powered up the meter, the needle slowly swung to full scale and pegged. Did the troubleshooting procedure outlined in the manual, checked the thermocouples and one of the two is out of limits.

The good news is that sphere has a couple in stock. The bad news is they cost $60 plus shipping.  So a couple more 3400A questions before I spend three times what the meter cost me for a single part 

1. If the thermocouple got fried, how likely is it that the chopper amp is damaged, too?

2. What's the likelihood of randomly finding another 3400A parts mule with a good thermocouple?  Seems like the easiest part of the meter to damage.

Thanks!