TV, power failure: optocoupler 817 to be replaced?

[phil59]

I got a broken TV from a friend.

A priori, power failure, mains input ok, but I found 2 components that seem to be out of order ....

Optos couplers a priori, and as I don't know anything about it, do you have an idea of ​​what I could put in the place, 817 BW L1237 ... 817, I see plenty, but are they the good ones? ????

817 bW.jpg (34.47 KiB) Viewed 4491 times

[Christophe]

It's a bit like the jungle of electronic components.

During one of my projects I had found this site which gives equivalents for each component at the end of the page: https://www.el-component.com/

Example with an IRF1010Z Mosfet: https://www.el-component.com/mosfets/irf1010z

I'm not strong enough in electronics to ensure that the equivalences are good on the other hand... I only know how to read and compare datasheets!

Unfortunately it seems that there are no optocouplers on this site...

[phil59]

l817.JPG (55.49 KiB) Viewed 4406 times

https://www.tme.eu/Document/f407c9d494e ... -817-B.pdf


A beginning of explanation of what is written on the component.

So it will be easier to find!

The postman, not too awkward a priori, depending on what is in front ....

[phil59]

On Ali, or a French site, it's about the same price, what changes is the price of delivery.

There, about 2€ on ali, for 20 pieces, delivery included.

[izentrop]

I found 2 components which seem to be hs .... Coupler optos a priori

Have you tested them?
https://www.circuits-diy.com/pc817-opto ... r-circuit/

[phil59]

If you read the beginning, out of the 5 there are, 2 have infinite resistance, without knowing what is before, or after, of these components.

It's a start. I don't know enough to be able to do a real analysis, having a resistance, or impedance behind, doesn't mean that the others are good, but no resistance, it's a pb.

[izentrop]

of the 5 there are, 2 have infinite resistance.

on the transistor side it's normal, it's like measuring 2 diodes head to tail.
On the LED side, the same, with a current multimeter in diode measurement, the voltage does not exceed 2 V, not enough to circulate a current in the forward direction of a LED whose threshold voltage is 3 volts.

[phil59]

I made several measurements, in one direction, then the other, between the different legs.

Like I said, it's not real news, but there are suspicions.

Why 3V, it's a 9V battery of the "thingy".

[izentrop]

Why 3V, it's a 9V battery of the "thingy".

It's the normal threshold voltage of an LED, but in the datasheet they indicate 1.2 v, it's an infrared, so it must be measurable with a multimeter.

9 V is the battery voltage of the proposed tester circuit.

[phil59]

Why 3V, it's a 9V battery of the "thingy".

It's the normal threshold voltage of an LED, but in the datasheet they indicate 1.2 v, it's an infrared, so it must be measurable with a multimeter.

9 V is the battery voltage of the proposed tester circuit.

Yes, what is your method for testing with the only instrument, a multimeter, without desoldering anything?