Recapping the inguard PCBs makes them much more reliable.
Just resurrected my 2th 5440B by just recapping the inguard regulator board (last board in the back).
It had random "inguard bus failure" fault or something, especially during warmup, when it needed most power.
Almost all electrolytics in the inguard section have really bad ESR in my units, especially the yellow 22uF/50V ones. Capacity is more or less fine, but ESR is really bad, 1++ Ohm usually. I'm currently in the process of recapping all inguard boards with better, larger capacity electrolytics to fix them completely.
3th 5440 has display problem and also problem with PSU and power distribution on backplane, backplane connectors got damaged during shipping some times in the past, probably because heavy transformer wasn't attached with screws. But shouldn't be too hard to fix once I have 2 working ones.