Impedance - what if...

[Alex SE]

I've recently found out that identical two of my cassette decks have a infinite (?) impedance (DMM showing OL). I won't ask why, there have to be some reason, but wondering if that and which way affecting a functionality of a decks.

Any ideas?

 

[NavLinear]

Check this out and see if it helps.

https://www.hioki.com/us-en/learning/how-to/u-impedance-meters.html

 

[WOPL Sniffer]

But WHY is the red one purple????

 

[NavLinear]

Because the purple one is red.

 

[Alex SE]

Seriously?

Check this out and see if it helps.

https://www.hioki.com/us-en/learning/how-to/u-impedance-meters.html

You mean that input impedance can not be measured with DMM?

 

[mlucitt]

I've recently found out that identical two of my cassette decks have a infinite (?) impedance (DMM showing OL). I won't ask why, there have to be some reason, but wondering if that and which way affecting a functionality of a decks.

Any ideas?

You did not mention which cassette decks you have. This would allow the tape heads on the forum to likely give you an accurate solution.
I am wondering if there is a relay on the input that latches when the tape transport is put in motion.

 

[Alex SE]

I appreciate that you want to help find what is wrong with decks and I would be happy to find out but I don't think we gonna solve that mystery.
It's about two RS-B965 that are modified. 6 transistors on the input are replaced with resistors (leaving transistor base disconnected). Otherwise than that nothing except replacing some IC's with some better and placing 0.1uF caps between V+ and V-.
According to SM a decks should have input impedance 47K.
As I wrote, I'm not expecting anyone to find a problem ( would be both happy and surprised if someone could), but wondering if infinite impedance somehow affects decks functionality.

Answer on your question: transport is not engaged, deck is ON and in SOURCE mode, nothing else.