Thanks guys,
The machine is Dalex-Werke make (German company that still doing good), VDE 0542, Type CGL 160. It is MIG welder. Well, I have searched for the diagram or some other information but without luck. It is vintage machine nowadays so no surprise that there is no info online. I even wrote an email to Dalex company but no reply. So far I narrowed the problem to minimum and I doubt that I could get some info on these diodes on the particular make. My guess that these are quite common diodes of that era.
Unfortunately I do not have square generator and I am not sure that I would be able to measure with certainty even if I had it. Looking at the machine I believe that diode must be slow
Yes, I also came across to these Telefunken BYW85 but was not sure at all on that. Are avalanche diodes used in diode bridges? Initially I thought it should be very common diode. I found out that my local supplier could deliver me Vishay 1N5627-TAP. Does this "TAP" extension matters? Probably it is worth trying to use these 1N5627 and see what happens next.
Well, the wire diameter on original diodes is only 0.3 mm (not even 0.85). Actually 1.35mm is a really beefy one. Yeah, and the body of 1N5627 is 4mm while mine is about 2.5mm. Hmm, 1N5627 seems to be something other than original ones.
Nope, I rechecked with ordinary caliper and the wire diameter is 0.6 no 0.3 as I stated before. The body is somewhat 4.5mm and diameter 2.7mm. I used digital one before and realized that it can not be 0.3.