Finished build of the incandescent light upgrade to the IBM 1130 control panel

 LAST STEPS IN ASSEMBLY

There are only two remaining steps to finish installing all the components on this board. The first is another large tedious operation - placing 164 single header pins on the board for all the logic signal inputs. The second is quite small by comparison, installing the three wire terminal blocks that provide 7.5VAC, Lamp Test signal and common ground connections. 

By mid-day I wrapped up the signal pins and moved on to the terminal blocks. Since this board used 2 ounce copper pours for each layer, it has a very noticeably higher thermal mass than the usual PCB. It takes quite a bit of heat, with a wide tip, over a longer than usual time to flow solder properly through the pins and holes for the terminal blocks. 

VISUAL AND BENCH CHECKS COMPLETED

I carefully examined the soldering of all the sockets and pins by eye before starting tests with an ohmmeter. I then checked for zero ohms across the three power/control input terminal blocks. Finally I tested every socket and every signal input pin for signs of a short. Everything was good. It was time to apply some power and check things out.

Finished board ready for testing