When you are repairing full nut units, you may find different zebras, that may or many not be corroded. Here is a picture of the three different models of zebras, plus our own:
Today's message refers to the first set of zebras. On one side, they are the least common; on another, they have also the highest resistence, which is good enough for a calculator to work, but makes very difficult to operate peripherals - and in some cases virtually impossible - in particular the card reader - that power hog.
If your card reader seems anemic, this may be the reason. The second pair in principle should work - but I had unconsistent results with it. The third is the best of the originals, and works every time unless it is corroded or broken.
We have found that the replacement we have designed works every time. The connectors are exactly aligned with the upper and lower contacts, and there is no way it cant work unless corroded: no mobile parts, very solid and thick circuit paths, and there is no topological way for it to unfold after being put in the machine.
You can find it here: