Word of warning if you are like me, and wanted nothing to do with electronic sirens because of their supposed “difficulty” do not judge them till you work on one.
Also a word of thanks to 4j25 for his help and his contributions to the knowledge we have on the Alertronic. My post is not meant to really be a post on their history, but on how their controls work. I am also not going to touch on the heads because he has already covered it.
A while ago my company was contracted to work on an Alertronic siren up in the Northwoods of Wisconsin. Up until this point, I believe the community did not know much about how these siren’s controls worked. At this point in time, the community only had one decent quality photo of the Alertronic Series controls. The controls in the photo were from the old Sarnia, ON siren system that the user Siren_Dude posted. In the photo, you can see a 6 button assembly with a microphone, a circuit board assembly, some sort of time delay relay, a fairly large relay, battery charger, and an outlet. At this point in time, I believed that the circuit board assembly in the top left corner of the photo was the “Brains” of the unit and thought that that was what generated the tone. Through my experiences, during the restoration of their Alertronic AL-6000R I found some valuable information that I hope can help the siren community.
The Control Assembly. From what I can tell the Alertronic Series went through three different styles of control assemblies.
Style 1 1983?-1991
Photo credit Siren_Dude
The internals of this controller came with the following, 8 200 watt variable power amplifiers, what I believe to be the original “brain” the Alertronic Series used. A 100 amp 24vdc contactor, and a LeMarche battery charger. The controls also had room for a radio or telephone relay depending on what the customer ordered. These units can be found with both the fiberglass and metal rectangular battery boxes. This is what the Sarnia and one of Wisconsin Rapids units had. This style of controller would be found on all AL-6000R’s ever produced and AL-4000’s of the period. This version of the controller would come with an LED diagnostic box if the customer ordered it. An example of this can be found on the Menominee, Mi AL-6000’s. I believe that is the same style of controller that the oak ridge Alertronic AL-7200
Style 2 1991-1994?
Witter Field, Alertronic Controller *Note Alertronic board was already removed*
This was the 2nd edition of the Alertronic controller produced under ACA. This controller came with the following upgrades, use of 400 watt amplifiers, Revision B “Brain”, a 100 amp 24vdc contactor, an off delay relay, a radio or telephone relay depending on what the customer ordered, and a Schauer charger. This style of cabinet is found on any ACA Alertronic AR-1600’s and later AL-1000-8000’s. It was also used on the early Quadrens up until about the point that ASC was bought out by Hormann possibly a few years after.
Style 3 2007?-present
This is your typical ASC Electronic siren controller that you would find on any new ASC electronic siren installation. This controller features the same 400-watt amplifiers found on the style 2 controller, a PLC relay, 24vdc 200 amp contactor, Guest 3 amp chargers, and an integrated CompuLert radio/tone generator. This is when ASC switched over to digital tone generation for all their electronic sirens and stopped using analog tone generators.
The “Brains”
As I stated in one of my last posts, ACA did not design or produce the Alertronic Controller most of it was the workings of Carson Manufacturing located in Indianapolis, IN. They designed and produced the amplifiers and Brains for ACA and potentially still for ASC. The Alertronic is nothing more than a police car siren; the unit even shares the same buttons as the Carson SA-400. The main “brain” of the unit is not as complex as a SiraTone by any means and was actually quite primitive and simplistic for its time. The Alertronic has 9 Integrated circuits, in contrast, the Siratone has 17. The siratone was capable of 6 different signals, an auxiliary tone, onboard signal timing, rotation control, and frequency-changing, and live voice. The alertronic was capable of producing 5 different signals, live voice, and a button to rotate the siren. The Alertronic board also has two onboard relays, one to control the rotator, and one to control the amplifiers. They always engage together whenever a signal is being generated or when live voice is being used. The only time that the rotation relay engages separately is when the rotation button on the controller the siren has no onboard timer and relies on an external contact closure to make the signal duration. One thing to note is that these boards have onboard audio amplifiers two for each channel it looks like. Unlike the SiraTone that outputs in stereo when the Alertronic outputs in dual mono. On the boards it is signified as AMP 1 A&B and AMP 2 A&B. AMP 1 is the 654Hz square wave tone and AMP 2 is the 763.5Hz tone. In an Alertronic that was ordered in Single-tone, the factory would only have the amplifiers fed with audio from either the AMP 1 or 2 outputs. In Alertronics that were ordered in dual-tone, half the amps were fed by the AMP 1 output and the other half by the AMP 2 output. Contrary to popular belief, the Brain did not generate the soft start that all ACA and ASC products have. The siren’s soft start is due to the amplifiers starting up from being completely off. In Federal Signal products the amplifiers have a constant supply of power. When the siren is not running it is kind of in a “sleep mode” not pulling very much power waiting for a main incoming signal to be amplified. In the Alertronic’s case, the amplifiers only have power when the main 100 amp relay is engaged by the “brain”. The board is powered by the pins labeled POS and NEG above the signal output pins. The board has a set of pins where you can connect a radio or telephone relay via an ACA supplied wiring harness. Most of the time the radio came prewired with the harness.
Alertronic CP-3624 board on the right, SiraTone on the left.
Carson CP-3624 or the “Brain”
This is the first Alertronic brain. It was probably used on the 5000 and until the style 2 control cabinet was made. These boards from what I could tell were very temperamental. Of the two boards, I have had, both have had some sort of issue. The first issue with the boards is that they were prone to blowing the 4.6K ohm resistor that is in line with the onsite activation buttons. On both the boards, I had they both had the same exact resistor burn out. Another issue they had is that their hex inverter was very susceptible to damage. The first board I had experienced a catastrophic failure of its U9, which is a Motorola 14069 Hexinverter. That particular board whenever that particular board received power it would automatically start-up in the alert signal and would not stop until power to the board was removed. My current board when I received it already had the same resistor replaced and also had U8 which is also an MC14069 Hexinverter replaced. When I went to test the signals on the board all of them worked except for the Hi-Lo signal. This led me to believe that this board was also experiencing a hex inverter issue. I ordered some new old stock MC14069 chips off of eBay for the price of $3 apiece. When they arrived I placed one in the chip holder that was already installed in the U8 spot; it did not resolve the issue. Once I became more comfortable with my soldering skills, I ordered a brand new Texas Instruments CD4069 and soldered it in. Low and behold, I was able to get the Hi-Low signal to work again. Between my time soldering on two of these boards, I can say that the old wife's tale that these boards were "flammable" and that the minute you tried to solder anything on them that they would burst into flames is untrue.
Carson CP-3624 Revision B
When the Alertronic series received an update in 1992, so did the main brain. The update saw a more condensed cleaner looking. From what I can tell the newer boards seem to be more reliable than the older style. This board featured a different pinout than the previous board, so the wiring harnesses are not compatible with the original CP-3624. The board also had fewer resistors which I assume added to the reliability of the board. When during my studies of these sirens I reached out to Carson to see if they had any information on these. At first when I asked they did not know what I was talking about, but when I mentioned that it was part of their contract manufacturing program they were able to find their file on it. They said that they do not produce this style of the board anymore, but they do have one left on hand for historical purposes. When I asked if they would be willing to bring it back into production, but they do not have any of the original documents. They said if I would not mind paying a design fee and ordering a large quantity of them that they would be willing to make some up for me. Needless to say, I do not think that the demand in the community is high enough to resurrect it from the dead. They were kind enough to send the schematic of the board for troubleshooting if I ever get another one.
The CompuLert electronic siren controller
This is the controller of any modern ASC electronic siren uses. It is an all in one tone decoder and tone generator. This was the first digital tone generator that ASC used. Note the relay above the fuses. The relay on the board just like the controllers before it drives an external contactor to power the amps just a slightly larger one than previous models. Any digital ASC Alertronic uses this board. I have yet to find an Alertronic installation that came with this board originally, but it is not out of the realm of possibility.
Carson 083C0005 200 Watt Amplifier
This was the amplifier featured on the style one cabinet. As stated earlier the amplifiers were capable of producing either 200 watts in the Hi setting and roughly .5 watts on the Lo setting. As you can see on the side of the amplifier that it blatantly states that it was manufactured for Alerting Communicators of America by Carson. I do not know too much about these amplifiers other than they seem to be pretty robust. Compared to a SiraTone amplifier these are very simplistic. They were only capable of four functions on, off, hi-power, or low power that is it no bias detect like the SiraTone and no diagnostic ports like the SiraTone. My apologies for how dirty the amplifier is, it was exposed to the Wisconsin elements from 2012-2019 and I am doing my best to attempt to clean it up.
Well, this pretty much concludes my post if anyone has any questions feel free to post below and I will try to answer them to the best of my ability.
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