Author Topic: Phone in Use Indicator  (Read 400 times)

Offline princessphone

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Re: Phone in Use Indicator
« Reply #15 on: March 18, 2021, 01:15:23 PM »
Hello Ken. You may be on to something. The electronic shop said that 2N3392 has been replaced by 2SC945. She said the were the same. How can I verify this? The markings on the transistors are  945 over K 81A .
John

Offline Key2871

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Re: Phone in Use Indicator
« Reply #16 on: March 18, 2021, 01:24:20 PM »
Hi John, is try to cross reference to see what it comes up as in Google. If it comes up as a NPN (Not Pointing Near) then it should work.
There is a way to test transistors in circuit, but let me see if I can find how to do it.
Do you have a VOM?  Volt ohm meter.
If so great because you'll need it.
And while your at it check the values of the resistors to verify they are actually of correct value.
KEN

Offline princessphone

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Re: Phone in Use Indicator
« Reply #17 on: March 18, 2021, 02:05:01 PM »
Hello Ken. On computer I found about 60 or so equivalent/replacement transistors but non matched the one I was given. The shop is not far from here so I'm heading there. I'll keep you posted. I have a good analog multimeter.  John   

Offline Key2871

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Re: Phone in Use Indicator
« Reply #18 on: March 18, 2021, 02:08:54 PM »
Hope they have a chart to tell you for sure. Good luck.
KEN

Offline princessphone

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Re: Phone in Use Indicator
« Reply #19 on: March 18, 2021, 06:23:09 PM »
Hello Ken. Found the problem. Got the terminals mixed up on the transistors. The instruction book (page 15) shows a picture of a transistor with E,C and B in a wrong line up. Sorry for wasting everyone's time. It's working properly. However the red LED glows a lot less than the green LED (same types). Also with the red LED on, the green LED gives off a very low glow. One more thing of note My Viking Ring booster has 2 red lights. One for power which stays on all the time, and another one "LOOP" and only comes on with of-hook. Now with my Line in Use Indicator the loop light glows a bit constantly.
Thank you all.  John DeJonge
PS Perhaps it will function a bit better when I get the proper transistors. They are on order.     

Offline Key2871

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Re: Phone in Use Indicator
« Reply #20 on: March 18, 2021, 06:41:55 PM »
Good deal, yes some times the emitter and collector can get mixed up, but glad you found the problem.
Yea since you have another circuit doing almost the  same thing that will draw a bit more current, if you disconnect the Viking unit, does the light glow brighter?
KEN

Offline princessphone

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Re: Phone in Use Indicator
« Reply #21 on: March 18, 2021, 09:35:22 PM »
Good evening Ken. Sorry for delay. Had a couple cold ones with neighbour. No noticeable change in light output with Viking disconnected. I'll wait and see with the correct transistors. I didn't really need this unit. It was just a project and challenge for something to do. Thanks for the interest you offered. Best regards. I really like this forum. Don't know why members argue.  John   

Offline Key2871

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Re: Phone in Use Indicator
« Reply #22 on: March 18, 2021, 10:24:05 PM »
Its human nature for members to argue. As unfortunate as it may be..
KEN

Offline 5415551212

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Re: Phone in Use Indicator
« Reply #23 on: March 18, 2021, 11:25:40 PM »
Sorry for wasting everyone's time. It's working properly.
Its not a waste of time, this is what this forum is for.
Were all hear to learn.

Offline Key2871

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Re: Phone in Use Indicator
« Reply #24 on: March 19, 2021, 05:25:37 AM »
Exactly, this is a great place for help, and learning.
KEN