I have been planning on doing this for some time but finally am getting around to it.

Project: Completely rebuild a D5500 power supply module.

History: I have 4 power modules that work with varying degrees of competency. One blows bulbs occasionally and another works except the light won't go on. Another works but the filters 'hunt' a little too much.

The service manual recommends "Power Supply Board Replacement" for all the above conditions. F-point used to carry Omega parts and had a brand new power supply board listed for $200 USD for many years. I was going to buy it as a spare but it turns out they got out of the parts business. (I sure hope that power supply did not wind up in the trash. :o)

There really are not that many components on the power supply board and it looks like one could just replace all components to re-manufacture a brand-new board.

Component Selection:

Even though D5500s were available new into the late 90s, it appears they were assembled from batches of components that were acquired when the enlarger was first introduced in the mid 80s. So, most all of the semiconductors in the power supply are outdated.

I used the D5500 shop manual parts list and the schematic, along with detailed visual analysis of each part. Paying attention to matching operating characteristic and mounting hole pitch and component size.

After a lot of internet searching and analyzing all the component datasheets I came up with a list of every component on the power board except the two transformers and the ribbon connectors (which I plan to leave in place). Everything else has been sourced and will be replaced.