[dseymo1]

I wonder if this bodge evolved the other way round? If the 'repairer' found the missing supply, perhaps he used the wall-wart to feed in volts and check his diagnosis and that there were no further faults (I might do something similar myself). Fault confirmed, he finds that he has no suitable replacement diodes, so tries a standard rectifier on the off-chance, but no go. OK, let's tidy up the test lash-up a bit, and leave it in place while the correct diodes are on order to keep the set going. Then, as often happens, something or other intervenes, and the proper repair never gets done.
Doesn't excuse it, but perhaps something of the kind explains it.