VKID1620 Voice Identifier (manual) RCS4602s How it works ... correct to January 2 1998 The Amplifier section. We have chosen a LM386 monitor operational amplifier, simple, cheap, effective and it works from other well proven projects. Bernie Orbell went over my values and has used this IC to oblivion with great success, so usual care in inserting the IC, whilst this is not a sensitive cmos device, mechanical care is of most importance. The supporting components are R11, C10, C14, C15, C16, C17 and of course an 'el cheapo' 8 ohm car speaker whatever, connected to the monitor output points. Turn the power on and put your finger on the trimpot RV3, listen for the 50/60Hz mains hum at the speaker, if the hum is NOT present, turn the trim pot fully up and try again or use a screwdriver as an aerial to listen to rf scrunch. As soon as you hear the hum assume it works ok for the next stage, so return the trim pot to the 12 o'clock position and turn the power OFF. You will notice, unlike most magazine projects, all the trim pots are connected correctly with max sweep being clockwise, crikey there are only 8 components in this part of the circuit, even you cannot stuff it up. Beware of the polarisation of the 3 electrolytic caps. C10, C14, C15. The VOICE RECORD/PLAY Section is possibly the most technical on the board and the least spoken about because what's inside the ISD1416 really does not matter, as we cannot tailor or do surgery then the insides are of little consequence, suffice to say it is a 16 second endless loop cassette, reasonably thick tracks are feeding this IC with a 470uf at the area 2D to support minuscule surge currents at around 80Hz. (according to Bob Parker a mate of mine.) The AGC according to the good book says a 470k and a 4.7uF are needed to ground, but BP with many years of experience with this device says the book is wrong, use a 1meg and 1uF, now who do you believe ISD engineers who designed it ? or a real world technical usage from Bob Parker, We will use 1meg/1uF. After ensuring all the voltages are correct on the IC socket, ie. no evidence of +12v ANYWHERE, and checking the +5v power supply is ok, now turn the power OFF, CAREFULLY insert the cmos ISD1416, remembering the rules/guidelines on handling cmos regarding friction/static/grounding. The ISD chip is in and if all the voltages were correct, then when the power gets turned ON, no smoke escapes from the IC, one can assume that all is well. This board has been designed with a fool proof (where have I heard that before) safety device installed. Look carefully around the 'see through' checkplot area 3F. What we have here is a safety 2 pin setup. The 2 pins are shorted out underneath, it is time to cut/scratch the join and make sure you have soldered in the 2 jumper pin devices, these jumper pin settings are the same as those on the old hard drive DS lines and nowadays master/slave settings. This board has a set as mentioned earlier, put the shorting pin across the 'REC' SAFETY at area 3F, thus allowing the RED Recording Push Button to work. By being about 6" or 150mm away from the board, having rehearsed your 15 second speech hold the RED Button down for the length of your talk. You will notice that the RED Record LED (LED1 area 6 I) illuminates to indicate 'on air', now to hear your master piece, simply press the PLAY (yellow/white PLAY E Push Button) , this plays the message entirely. A hint here is to allow about 1 or 2 seconds pregnant pause before your speech, thus bringing to the attention of the listener that 'some thing is coming', anyhow whatever turns you on. REC record and play your talk This should boom out through the monitor amplifier IC2. The volume of this device has NO effect on the final 'injected' volume to the repeater. The output comes from the IC1 through to RV2, a 10k trim pot. This has a screened cable going away from the line out to whatever you want to go to, you have a relay on board, or you can use the relay on board to operate another relay 'off' the board (double pole) to operate 'inject audio and PTT' your choice. So RV2 effects the repeater announcement volume and RV3 is the monitor. Now you have your special announcement in the ISD, you can do the following, use a tape recorder from the 'line out' download a safe working copy, or reload at the 'line in' section, (Line in info at the bottom of this article) there is a little mod to do. And lastly remove the SAFETY PIN Jumper and put it sideways with only sitting one pin. It makes no sense doing an excellent recording, only to accidently, wipe it out by touching the red record button. An 'EXTRA' is on this small board to assist in PTT, a small relay DSE P8005 (Dick Smith Electronics 5v Relay), the relay obtains it's supply from the +5v regulator and through the coil, to Q1 an ordinary npn silicon transitor type BC107, BC547, 2N2222 - anything. The transistor obtains the base drive current from Pin 15 of the ISD, it has a 10k inserted in between the Pin 15 and Base of Q1, more than adequate non- loading of the ISD chip, whilst my device worked ok, in theory if the voltage swings on the ISD are too savage ie high/low it may be enough to 'loose the relay', please if any body experiences this let me know immediately, and I will mod the circuit, include a 10uf or 47uf on the base to ground of Q1, to limit the npn transistor from dropping out prematurely, (that must be my problem also in the cot), any how back at the ranch, the relay is operated (ON) for the duration of the message. I have no doubt this board could have been designed smaller, however this board follows all the military design rules. All diodes point north, all capacitors point north with the negatives - pointing south, and of course all the IC's point West>East , this does cost space but the benefits on assembly and fault finding from poor soldered joints are immense, and this is done this way so the earliest of amateur entrants can build this project with a minimum of questions being asked of me. The components have been laid out in 'sections' so as fault finding can be reduced to a minimum of decision between faulty components or excess/minimum solder. The only LED on this 'no frills' unit is for the RECORDING LED, very important !!! +12 to +18v is quite safe to put on this board, the +5v (7805) will look after the rest. * Line in modification. You will have to choose if you want to load the repeater ID from a microphone or off a tape recorder. If you are going to use a tape recorder line procedure, then look at the area (5 F) and locate resistor R4. You will notice another hole, move the southern end of the resistor to this hole and re-solder, so as to put the 'Line in' pot RV1 in circuit. An auto loader was developed off an IBM computer for this purpose many years ago for other applications using your sound card, *.wav files etc..., this is the correct way, but what the hell this is a personal voice ID, not the Boston Pops Orchestra. Remember this board is meant for the shack and personalisation messages recorded 'on the fly' you might say, or calling out those repetitive CQ's long into the night. Any smart tech can automate this, hang on, that is what the 4600s already does !!!. That is all for now, if I can answer any FAQ's then I will add them here, thankyou. Bob Barnes VJ2R send an email or +61 2 9587-3491