A strange behaviour when my classic calculator is connected to a wall adapter

[aurelio]

(04-24-2020 12:52 PM)Paul Berger (Canada) Wrote:  

(04-24-2020 11:03 AM)aurelio Wrote:  to avoid misunderstandings, the switch is not faulty at all, it is only taken apart and I'm not sure how to insert the springs into putting it back, I guess the flat part towards the slider . The selector was positioned correctly, so I don't think the transformer gave on the output a much higher voltage, but I will take the time to carefully disassemble and test everything.
I found this interesting site where David proposes an alternative schema
The problem is my local electronics shop doesn't have the NTE ones suggested by .

I have found in many other posts regarding the topic also an interesting conversion table provided here by Katie, but unfortunately those indications did not help me and the seller to find them
Somebody may help in that?


Edit: I found the equivalents, not without emotion, here on the Jaques Laporte site, thank-you Jaques

The flat side of the contacts in the switch go against the circuit board so that they bridge the pads on the board.

I have fixed a few of these chargers and the most common fault I have found is breaks in the cord which are often deceptively intermittent. The most common place for them to break is near the calculator connector. Try flexing the cable a bit while measureing the output.

I have replaced the transistor in the logic supply, a MJE800 in at least one but I don't recall if the symptom was low +5 or none at all.

Paul.

Paul, I've checked the integrity of the flexible cable at first and again after each attempt, it's OK, my suspicious is to have damaged the components while testing the voltage in different points of the circuit using unproperly the probes .
Infact at the beginning I had the constant current supply (16,4 V) and the logic supply
4,9V (unplugged the calculator), maybe this second value too low, but now I get just ,03/0,2 V) instead...aargh

waiting for the replacement parts...