HP- 67 1706A04606 - keyboard repaired weird behavior

[albertofenini]

Hi everyone
trying to make an HP-67 work, we have discovered that the numeric keys
had the underneath domes broken

We have transplanted those from an HP-45 and it may be interesting to see how
it looks now, we have followed Teenix's procedure, drilling a small hole in the
donor keyboard and soldering the strips on the HP-67

Being the firs time we are quite happy, but it could have been done a little better and nicer

Anyway, this unit was used last time in March 2021 and put away in working condition without batteries

Now, when the batteries are put inside, it doesn't turn on at the first try,
some faint numbers appear on the screen and then nothing

Sometimes keeping pressed a key while turning on does the trick, but not
always

Some times show a list of 0 and the keyboard is not responding

In the end, we have found out that if we leave it on, after a while a 0.00 appears on the display and the unit works well

What could it possible be ?

Put it in another unit shows the same behavior

As for the card reader, it reads very rarely, it writes but it cannot read the cards
written by itself, these can be read without problems in a different unit

Also, it shows a behavior that has already been discussed in the forum:

When a double sided card is inserted, the first side is read correctly and prompt
for the second side, but the second side will always make the motor run a little
after the card has gone thru and then it gives an error message

Pictures and video can die found here : HP- 67 1706A04606

Thanks in advance for any help !!! Take care !