Do these connectors fit for an old HP3400A?
If the [hp] is made in what was then West Germany, yes, they probably fit. I've got a Model 400h VTVM made in the early Bundesrepublik that takes that connector.
It's an US one.
Then you need a PH-163 as Cubdriver wrote; the Heizgerätestecker won't do. Good luck. I've got two, one with my 5221 and one with my 200CDR. I also have about 100 ordinary C13 cables. And a batch of Heizgerätestecker, which still can be bought as NOS. (A lot of toasters, waffle irons and other appliances here take the connector, so there is a large non-TE "vintage chic" market. )
I've got loads of German built
hp, none have that Heizgerätestecker, they either have the PH-163 for the 1960s build units and fixed power cords for the older ones. The odd connector most have been a custom order
or a fixed cord/PH-163 inlet that got replaced.
P.S. last time that 3DP connector was mentioned, I thought the crimp connectors used were crap, need to be proper split spring type, the male molex type crimp has the split piece
not the female one they used. Have bought the odd one that was bodged with crimps and they were always a sloppy fit.
P.P.S. I seem to recall the IEC version of the 3400A has the voltage selector slightly higher, to clear the inlet, I might still have the IEC rear panel from the donor unit, that I scrapped to repair several others.
David