..
Sir Robertfhegreatnewb. . . . . . .
In response to your perceived and implied . . . . . .Say whaaaaaaaaaaaaaaaaat ? ? ? . . . from our Right Revered, Honorable and Esteemed . . . . . hevans1944 . . . aka . . . "the hopster".
Let me initially give you some design parameter insights of those two paired units that you are hoping to use.
Looking at the transmit board:
At the very right top corner is the oscillator/transmit transistor . . . . . . .refrain from WANTING to straighten it up vertically . . . as it will probably snap a wire lead in the process.
At the left is the 14 pin Pericom encoder/decoder IC which gives a coded digital modulating of your transmit signal. This way your unit will not be erroneously ringing a like branded doorbell of next door neighbor Tilly the Toiler , or Ivan the Terrible across the street or even 'ole Granny Goodknockers, a full two houses on down the street..
Next item of interest is the metal "sardine can" at the end of the IC . . . . if it has 2 leads underneath it, it could be a crystal related to the time base / clock of the 14 pin IC . . . or you could find a 27 or 49 numbering sequence on its metal case. In that case, still being a crystal, but transmitter stability related.
If it has 3 or 4 leads it will be a SWIF filter, related to the frequency stability of the transmit RF oscillator circuitry.
Dropping down from the mentioned "can" will be seen, the foil side profile of the etched copper hairpin loop that is associated with the inductive element of the transmit tuned circuit and is also being the units transmit "antenna".
With that info now known . . . . best that the unit now receive its outer housing . . . . . to space the circuit board out from the detrimental detuning / loading effect of having ones hand and fingers in CLOSE proximity or actual contact with the PCB proper.
Moving down to the receiver board:
Top left corner is the transistor (2S1815 ? ) that is the superregenerative rceiver of the transmitted signal.
The transmitter generated a transmit frequency that was basically a bit coarse in its accuracy, while the receivers top left ORANGE coil with its internal, adjustable brass slug lets the receiver be precisely tuned to the transmitters frequency.
The clutter of discrete support components and on board filtering between the receive transistor eventually presents an audio tone modulated signal to the input of the 14 pin decoder IC.
If the coding handshake is in order, the chip then passes a DC control signal to the brown phenol "daughter" board that you see mounted vertically at the very end of the IC.
Center, left side of that board is seen a black epoxy blob . . . .that is called a COB . . . Chip On Board . . . . it encapsulates / covers the integrated circuitry underneath it.
That circuitry is taking a DC start signal and then triggering the start of the one shot sequence of creating the tone, voicing and amplification of the ensuing audio chime action to
drive a piezo or PM speaker below.
Its interconnection, probably being the two BLUE wires, due to their proximity and directional layout..
That must leave the 2 yellow wires for power input ?
At the right center of the board I'm rolling around in my head, if that is an adjustable micro volume control for the chime circuitry . . . or if being a" tact" momentary contact switch . . .and wondering its purpose / need ?
Now, with you being minimally, "micro" educated for what you are looking for . . . . . .
Sleuthing . . . . .
Get the transmitter back to normal power up on both units and confirm a chime sequence activation, with the transmitter.
Working with the receiver portion:
Take a voltmeter with its negative lead connected to battery ground then use the other lead to stay at a random initial connection into the daughter board .
You are looking for one, of those several incoming connections into the daughter board, that shows a voltage presence for the duration that the transmit button is held down and drops when the transmit button is released..
Now sample all and see if you now can find one, or possibly others, among its series of connections that are coming into that daughter board.
THEN . . . . a possibility of accomplishing what you wanted, is now being in sight.
Question now . . . .does the chime seem to come from a small piezo-electric transducer or a conventional permanent magnet / coned speaker ?
Need to know what components I can take out without damaging it.
Hee . .hee . . .hee . . . . .If you are feeling a daunting . . .yet . . . unrelenting need of accomplishment . . . you just might go to the receive board and surgically extract the round cylindrical component between the IC and the daughter board . . . . it being of beige / black band / beige colorization and you replace it with a solid jumper wire..
Then you tape that component onto your trophy board on the wall.
Thasssit . . . . .
73's de Edd
.
