Thank you kindly for allowing me to join your forum. Through an unusual and unexpected circumstance, I became the owner of my old elementary school's master clock about 30 years ago after a brief conversation with my former and retired principal who had kept it stored in his garage after it had outlived its usefulness. To say I had developed an obsession with the Standard Electric classroom slave clocks as a kid would be an understatement. Since 2013, I have been slowly collecting vintage Standard secondary clocks ranging in age from 1939 to 1972 off of Ebay, successfully running them in sync using a little $90 Piexx 2" x 2" impulser that I power with a 5v adapter. My greatest desire is to run my clocks from the master but my knowledge of things electrical is probably just enough to get me into trouble. My understanding to date (if correct) is that the three cam driven contacts on the master open and close according to their respective designs, one that controls the minute by minute secondary clock impulse, one for the corrective reset on the 58th minute of each hour and one for regulating the length of time the bells ring. I am hoping to learn two things: (1): What specific type of power source(s) or transformer(s) would be used to convert or transform the voltage to 24vdc to drive the secondary clocks as well as the 58th-minute 48vdc override that releases the mechanism for any corrections? (2): Which terminal points or leads on the master would be used to connect to these sources. I have the punch tape that would drive the bell program (which I think is what most of the electronics on the lower half of the master clock contains), however, I am only interested in running the clocks? Thank you again. Geoff
Hello Geoff, Welcome! First off the master clock you have is a AR2 master. Looks like you are missing the back part of the case that would house the connections of the secondaries and the bell power. I have one similar to yours but mine was modified with newer DC rectifiers. The connections for the secondary clocks is on the inside lower end of the clock. I hope you have the case that has these connections. If you don't have the case alternatively you could use a laptop DC power supply and an run it to the 1st cam and send a 24v pulse to your secondary clocks. Of course you won't have the 48v pulse correction. I have a head of a AR2A master using a Dell 20V DC power supply connected to the 1st cam that drives 2 of my secondary clocks. Of course you need a 120v AC connection that runs the master clock and the cams. As for secondary clocks, only AR2 secondaries that have the 2 wire 1 coil impulse will work with the 58th minute correction. That would be your 1952 and 1958 secondary clocks you have pictured. If your running the alternative method above you could run either the AR2 or AR3 secondaries. I'll get some pictures of my setup and post them in the next day or so. I hope this helps. Respectfully, Gary
Thank you so much for your response, Gary! I wish I could express how meaningful this is to me. Many years ago, I went into one of the few remaining Standard Electric offices in Paramount, CA and spoke with a most helpful tech by the name of Charlie, who was very knowledgeable and most interested in helping me out and even drew up diagrams and sent me home with literature, etc. Job and family commitments back then kept everything on hold. (Also, I had no secondary clocks at that time). I'm very much looking forward to your pictures and comments. Geoff
For home use I would just send a pulse each minute. It is simple and reliable and will work with any slave you have or find in the future (voltage of slaves will vary ) A PC power supply is a good suggestion. If you had a lot of clocks it would be good to switch the AC after a transformer and ahead of a simple rectifier. This is easier on the contacts, but again, with the number of slave clocks you are likely to have it is not a problem.
Good Morning Geoff, You are very fortunate to have talked with Charlie. I've been gathering tribal knowledge for years on these clocks and there is not much in terms of technical documents or diagrams. Yes there are some but many of the AR type masters have very little technical diagrams to refer to. Attached are pictures of my AR2 master and AR2 secondaries that I acquired at a regional from another NAWCC member who had updated the power supply. The clock came with a very high level diagram with no technical details where I could trace out the wiring or micro-switch connections. My master has a problem sending the 48v correction pulse to the secondaries, low voltage reading. Thus my secondary clocks fall behind 1 min per hr. As you can see there is the back part of the case I was referring to, in the bottom you see the transformers and connections for the secondaries and bells. If you have a copy of those diagrams that Charlie gave you maybe we can put our heads together and get your master running? Yes there are alternatives to running your secondaries but there is a romance of having a master of the era driving them. Gary
Continuing my post above I thought it would be better to break out my alternative setup. Pictured is a head of a master clock driving a AR3 secondary. I originally thought it was a AR2A master but now I realize that it's a GRC master. This setup can drive any AR3 or AR2 master with no correction. As you can see I'm using a 20v DC Dell power supply connecting the power lead and first lead of the secondary to the front of cam #1. Then the 2nd lead of the secondary connected to the back side of cam #1. So every minute the fingers connect to complete the circuit and send a DC pulse to the secondaries. You don't necessarily need 24v if only driving a couple of secondary clocks. 18~20v is acceptable in this setup. You can also see the AC connection to the master clock motor. Shane Sevy has a site that has every type of AR secondary that was made, well almost. He has helped me with some of this setup. I got the idea for my alternative setup seeing his timestamp master setup. I hope this spurs some good ideas! Gary
This is amazing, Gary. Thank you so much for taking the time to explain and share your pictures. Your square secondary brings back immediate memories of our cafeteria / auditorium at school as well as some of the newer classrooms that had been built in the 60's. Keeping an eye out for one on Ebay. I have an 18-volt HP laptop power supply at the ready to try your method. Thankfully, the motor is already wired and functioning on the master's display clock. I see that your wiring is hooked to cam #1. Upon observation, it looks like my cam #1 holds the finger down for around 10 seconds, making me wonder if that would be the correction control on mine. My cam #3 has the shortest duration of any contacts being connected together. The PDF file that I attached on my initial post shows an "R" on cam #1 and a "D" on cam #3. I don't seem to have a key on that schematic to decipher their meaning.
Geoff, I confirmed on my AR2 master that the "MIN" is on cam #3 so your schematic is spot on. My GRC master has a different setup and uses cam #1. I must have got lucky when setting that one up. Gary
Hi Gary, I connected my clock wire with the HP Power Supply onto the same screw, then soldered the other clock wire to the back of Cam 3. Both the upper and lower connectors originally had wiring going to the actuator switch under the main drive wheel but there was no screw attached to the back of the cam, hence I soldered it. I'm out of terminal wire connectors but ensured that the clock and power supply wiring were tight. The following is an example of where my ignorance of electronics tends to swing into action. When I cut the end off of the power supply, I stripped away the shielding and the insulation, leaving only the center wire to connect. After connecting the clock wires to the clock, I turned everything on but got no response when the cam contacts came together. I tested the connection with a meter and it stayed zero. I'm surmising there is something I'm likely not doing correctly and would appreciate any input. Thank you! Geoff
Hi Geoff, Try soldering/attaching the power supply lead to the red secondary lead itself for a better connection. I marked that on your attached image. Your power supply looks to be sufficient. Give it try and let me know. Gary
Hi Gary, Still no success after soldering the power lead to the clock wire. Do you suppose it matters whether or not the power supply polarity is center negative or positive? The 5v adapter I use for my Piexx impulser is center negative. My HP adapter is center positive.
Geoff, Make sure you strip the insulating wire to expose the positive wire. I believe that's the issue. Gary
That's interesting. Mine does not have a hard center wire as shown in your picture. After separating the frayed wire in the middle, there is nothing else.
Good morning, Gary. Sorry for the delayed response. I continued to work with the HP power supply late into the night and even found another ancient 18v HP giant power supply that had the identical center, also to no avail. To be truthful, I don't know how to use a volt meter. Harbor Freight added this one as one of their promotionals after I'd made a sizable purchase years ago. Also, it suddenly dawned on me this morning as I awoke, that years ago I had purchased a 24v output power supply online in hopes of finding a way to work it with the master. I had totally forgotten about it and was able to find it today. One of the leads on the adapter has broken white lines painted on it while the other has writing. I don't know if that would factor in to anything. Geoff
Good Morning Geoff, The lead with the white dotted line is usually the positive lead. Luckily I have the same volt meter from Harbor Freight. Set your meter to the 200 DCV setting and touch the leads of the power supply to measure the voltage. If you get positive number like 11.1 that will indicate you are measuring the correct leads, red probe is measuring the positive lead and back probe is measuring the negative lead . I'm measuring a 12v battery. If you get a negative reading -11.1 that tells the leads are reversed, the red probe is measuring the negative lead and the black probe is measuring the positive lead. Good luck! You're getting close! Gary
Excellent! Thank you! Would it stand to reason that as with the laptop adapter, that the positive would join the clock wire? And at the risk of sounding foolish but nevertheless cautious, would the 24v negative lead connect to the back of the cam with the other clock lead? I guess I'm asking because I don't want to inadvertently keep something "hot" by somehow overriding the cam contacts.
I don't see an issue there, your completing the circuit either way. My setup is for testing only so it doesn't stay "hot" for more then a couple of hours.
Well, Gary. Your guidance (and patience) is paying off. I am beyond excited! I ran a test with the master against one of my five clocks, a 1962 round flush mount and it is responding to the 24-volt signal. However, it seems to be functioning oppositely, meaning, that it is moving the hand forward but it holds the arm to the magnets for the entire minute then releases it when the cam connects the contacts. However, the volt meter (thank you for the tutorial) is showing a positive 24 volts with the red probe on the positive and the black on the negative at the back of the cam. I'm wondering if what I was asking earlier would have anything to do with it as far as keeping the connection hot the entire minute by having the negative power lead connected with the back cam clock wire? Is it safe to remove the negative power lead and have only the clock wire connected to the back of the cam? I'm thinking in terms of your laptop positive being the only power source wire involved with your connection.
Great to hear Geoff! Yes go ahead and remove the the negative power lead for now and give it another test. That is the same setup here on my test clock and my bets are you will be running. Gary
Hi Gary, I was unable to get a response after disconnecting the negative lead. For whatever reason, when the negative lead is connected, the adapter is supplying constant current to the clock independent of the cam switch. Once power is turned on, it holds the movement arm fast to the magnets and doesn't let go until the cam switch is activated at the minute to temporarily interrupt but then it takes control of the clock again once the contacts separate. Geoff
UPDATE!! It dawned on me that constant power might be attributed to the positive wire being tied directly into lead clock wire. I left the power where it was and moved the first clock wire to the back of the cam, then connected the negative with the second clock wire on to a grounded screw that holds the power-outage flag into place. It worked like a charm and not only so, I am now running all five clocks from the master! A dream come true! And all credit to you for all of your help and input! Thank you, Gary!! ps: Compared to the Piexx impulser, the pulse width with the master is much longer (2 seconds?) from first click to second. Exactly like it was when I was in school. But I guess that makes sense since it was the same master. Geoff
Hi Geoff, I was just about to reply with some troubleshooting tips and just got your update. Congratulations!!! I have to say us pairing up and going through the trial and errors worked. I only know the very very basics of electronics and have much more to learn. Time to sit back and enjoy time pulse away! BTW my AR2 master is 1 year younger then yours 1955, came out of a Santa Cruz area school. What I like most about these masters is the mechanical back-up they have. Every now an then I wind them up and hear them tick away for a 24 hour cycle. Hope to stay in touch as I'm always playing around trying different setups, I'll let you know of any new finds or tricks. Cheers, Gary
Hello Moderators, Please make this thread a "sticky". Geoff attached the only known Standard AR2 master schematic. Many will find this schematic very useful. Thanks in advance! Gary
Good morning, Gary. I am still over the moon with all that has happened these last few days. I've had several individuals look at the clock over the years. I even took it down to Palm Springs where I had a database consulting gig for a couple of years, among a group of investigators who perform failure analyses on crucial medical breathing apparatuses, replicating the problem, etc. One of them was kind enough to clean up some of the components for me. They loved the clock but were a bit unsure on how to advise in getting it impulse-functional again. So, again, sincere kudos and high honors to you! Oddly enough, a couple of my clocks apparently got a little nervous with the change, e. g., the 1952 art deco clock starting losing a minute here and there as well as jumping ahead a couple of times. As well with my 1962. A few slight adjustments with the tension points and everyone is harmonizing once again. Since we've corresponded last, I installed a lighted doorbell button I'd picked up from Lowes and am using it to advance the clocks whenever needed. When I was using the Piexx impulser (great product!), I housed it in a cheap wooden box I'd found at Walmart along with a set of toggle switches that connect to the clock and power terminals to easily control shutting off any clock that might have jumped ahead. (Beats unmounting them from the wall). I've taken a few short videos showing the fruits of our labor and have supplied a few pictures and a couple of Standard Electric documents and diagrams that Charlie had shared with me years ago. I welcome anyone to view them if they wish: MasterClock - Google Drive
Gary, rather than make this a sticky, we have added "Standard Electric" to the list of prefixes for this forum. I have also edited posts for this maker back to 01/01/2016 to include this prefix. This should make it much easier for those search for them.
