Maker Pro
Maker Pro

FM modulator light only and no transmitting

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
I got f36ph zener diode they told me it's 5.6 v but how can I check
 

Gryd3

Jun 25, 2014
4,098
Joined
Jun 25, 2014
Messages
4,098
Only thing I can think of, is to connect a large resistor in series with it, then connect the whole string to a battery. You can measure the voltage across the diode.
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
271045.gif
You can test zener diodes using the circuit above. You will need a 9V battery, a resistor of about 330Ω, and your multimeter. Connect them together as shown. The multimeter will read about 9V. Then connect your diode as shown, with the cathode (the end with the stripe) to the positive side of the multimeter. If it's a zener diode, with a voltage less than about 9V, the voltage shown on the multimeter will drop. If it drops to around 5.6V, then your zener diode is right.

I can't find data on an F36PH diode but a 5.6V zener diode will probably have 56 in the part number somewhere.

Other part numbers for a 5.6V zener diode are:
1N5232B
1N752A
BZX55C5V6
BZX79C5V6
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
i have tested it and its 0.74
I think I can take the diode from the old board
so hope some one can supply me with draw for the new board
 

Gryd3

Jun 25, 2014
4,098
Joined
Jun 25, 2014
Messages
4,098
i have tested it and its 0.74
I think it will take while to get 5.6 v zener diode
Just making sure you connected the side with the band to the positive side of that test circuit. They are meant to be run backwards.
(The resistor will make sure you don't force too much current through during the test.)
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
can't we make the power circuit with different items that I can find locally
some thing like this
20141101_003348.jpg 20141101_003359.jpg

or like this

20141101_004018.jpg 20141101_004009.jpg
 

Gryd3

Jun 25, 2014
4,098
Joined
Jun 25, 2014
Messages
4,098
What you need it a 5V DC source... but you need to add that white wire to it, and couple the antenna with the 12V supply.
I am not familiar enough with the transmitter to tell you if you will have any results with the antenna portion disconnected or incomplete.
This is the reason I was on-board with Kris on the reconstruction of the original rather than just pluggin 5V to it.
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
I know.. I mean we can design another board like the one I show in the latest pic I believe they all provide 5 v with antenna as well
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
The second board in post #46 looks like it might work. It uses a 78M05 regulator which is not as immune to automotive voltage spikes as the transistor would be, but you can try it. Connect the white wire to the "RF" terminal, the red wire to the "5V" terminal and the black wire to the other terminal.
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
The second board in post #46 looks like it might work. It uses a 78M05 regulator which is not as immune to automotive voltage spikes as the transistor would be, but you can try it. Connect the white wire to the "RF" terminal, the red wire to the "5V" terminal and the black wire to the other terminal.

can you show me on board the points where to connect the wires?
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
I'm not sure because the markings on the board disagree with the colours of the wires that are currently soldered to it.

Plug it into your car and measure the polarity of the voltage between the red and black wires. If red is positive and black is negative, then connect your red and black wires to the same points that the old red and black wires were connected. If the polarity is the other way round, connect them the other way round.

Connect your white wire to where the yellow wire is currently connected.
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
ok I tried it gave me 5 v so I gather it all and tested it and the same problem it gave me light only
so I think the issue were not the power
7hhBX.jpg
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
I agree. I guess there's something wrong on the main board. I don't know what to suggest.
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
hmmm so what could be the problem is it the IC or what
by the way what is that silver thing that look like capacitor
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
Most likely the problem will be in the IC that's underneath the blob of black stuff in the corner. I don't see a silver thing that looks like a capacitor.
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
that thing beside the black blob what is that item it's round and tall..

I wonder if you can help me build FM transmitting board that read from flash drive and transmit it
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
That thing is a crystal. It is used by the microprocessor under the black blob as a source of constant frequency, so it can operate.

No, that's not something that can be made easily. A lot of programming is required. There may be projects for this kind of thing. Try Googling those keywords.
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
how about something like that
or this

I guess in the second video I can replace the mic with audio in as in the first video
but I wonder if I can do flash driver reader or that what is going to require programming
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
Right. Both of those transmitters are mono, but I assume you want stereo. That adds a lot of complexity. And yes, the code is needed to understand the data format on the flash drive, and convert the compressed audio files into an analogue audio stream. This is not something that is practical to do yourself because of the large amount of programming required.

Companies that make products to do it will write the code once and sell thousands of units, so the cost of the software development is very small on a per unit basis.
 

Gryd3

Jun 25, 2014
4,098
Joined
Jun 25, 2014
Messages
4,098
As Kris had mentioned, the time investment required to make your own FM transmitter that can read USB/SD card would be incredible...
There are multiple file systems that could be present on the USB drive or Card... there are multiple file formats, and bit-rates...

From here, you have two choices... cross your fingers and poke and prob at random spots on that main board and maybe perhaps a support component is faulty... Now that power is fixed the only idea I really have, is checking the IC for correct power... From there, it's all up to the mystery chip under that black goop which is not repairable.
 
Top