"kreed"
As for your case with valves and transistors, it could also apply to kits.
IIRC years ago, when you bought a kit from Dick Smith, you would be able to return it for a refund if, once getting it home, opening it and looking at what was involved, you didnt feel confident you could build it and hadn't started construction.
If there were IC's involved, and they were not handled with static safe methods before being returned, you could end up with a faulty kit, if you were the next owner of one of these returned kits.
** As I recall, ICs were supplied in a plastic bag and were inserted into pieces of conductive foam - whether they needed that or not.
By far the most likely reason for finding a bad part in a DSE kit is that is came from a shonky supplier. This was particularly true of TO3 transistors with "TIC" brand on them or later the Motorola "M" brand on them.
At one time in the late 1970s, DSE were selling LM741s that were out of spec and more than half were completely dud. I remember the logo on the packs was like a clover leaf.
The faulty transistors I bought were MJ15031/32s from David Reed in York Street. I purchased 5 of each and they were all shorted C-E. When I got a staffer to check the remaining stock with a multimeter - they proved to be all shorted too.
Then the truth came out, all the stock had been returned by another customer who had put them through a selection process to find the ones with the highest Vce rating. He returned all the ones that failed his test.
The faulty valves were GE brand 6L6GCs bought from Radio Despatch Service in George Street. I had returned four of them for making severe crackling noises only to have them turn up in an amplifier on my bench two weeks later. The owner of the amp had bought them from RDS a few days previously and he still had the boxes. They were the same ones.
... Phil