Home Forums General Discussion Technical Questions DMC Issue

Here goes. Customer made a call today. He was painting around the 2nd floor hall button. Wanted to remove the button faceplate from the wall. It was stuck from layers of paint, so he used his knife to pry from the wall. When he did the plate fell off the wall causing the wires to unplug from the button and hit the floor. He then thought O Sh**! Well he went to another elevator and pulled out the wall plate to see how it was wired. He got the wires hooked up, but the elevator would not run. No joke. Ok when I got onsite there were 4 blown fuses, I f2, f3, f4, etc. I have completely removed the button and still blow f2, f3. Removed wires to button in hoistway. Still blow f2,f3. Unplugged clc, still blow f2, f3. Wondering about the rectifier or the capacitor in that circuit. Any ideas??

Dont have the print in front of me but it sounds like you have a shorted diode in the controller.

What would be the best way to check the diodes?

I looked at a DMC 1 print and f2 comes directly off transformer into AC side of B2 rectifier and F3 comes directly off the DC end of the same rectifier. Now the question is what vintage DMC do you have? Is the relay board green or blue? If it is green, you may luck out and have a removable rectifier. Some green boards have soldered rectifiers and some have a plug in base.

It has the plug in rectifiers and has a selector. Can't remember the board color.

My money is on a shorted rectifier.I would meter it and see.

Diodes are checked with a dmm. Digital multi-meter.

Are you billing the painters company? This should be viewed as vandalism, I wouldn't touch the unit a signed proposal is in the works and will not perform any maintenance or take any calls unit paperwork is signed and proper documentation of the incident. Someone gets hurt on the unit in the next couple weeks now you are in a liability hell hole.

Checking Diodes is troubleshooting 101. It should read one way and not the other.

Thanks for the help, but I do know how to check diodes and what to check them with. There is no question in that the building engineer is at fault and this customer is quite aware of what happens to these units when power is lost, lighting strikes, power surges,vandalism,etc. It is never cheap when they are paying. I only asked about the diodes thinking someone would know which is likely the suspect. I know there is only a few along the bottom of the board to check so I'll be back at it tomorrow.

This is exactly what's wrong with our neiep education program guys. How is it possible this service tech is unaware of how a dmm works? ! The program is outdated and doesn't cover 25% if what it should imo. Where is the company training? We have some serious problems coming in the near future since half of our union workforce will be retiring in less than 10 yrs. It's hard to argue that we deserve raises and more bennies when our bros are lacking the knowledge to do their jobs. We all have to step up and teach the upcoming generation and re-vamp the neiep program to include more technical skills of troubleshooting electronics. Cmw007, Google it bud.

The old timers are just as bad. More than half of the t/s calls I get called out on the mechanics have over 20 yrs exp in the trade...When I fix something they don't care how I did it just that it works. You're right though NEIEP needs to make things a bit harder to pass the program, like a final hands on simulated t/s test plus written. But that might put our union in a position not to fill mechanic requests.

How do you know what education the OP has?

There's nothing wrong with NEIEP, they teach you how to use a dmm, wheter or not the individual remembers or understands how to use it is another question. It has been this way since the begining and will continue to be this way, union education or not. The question of ability applies to all workers, regardless of the employer, union or not, and even line of work.

Not everyone is an adjuster, nor should they be expected to be, but there is a place for everyone to do thier job. I agree that we all need to do our part to teach and pass on our knowledge, but this trade takes a lifetime of learning, and you will never master it.

I hear ya SSCjr, I had a bunch of those last week. There are some I come in contact with that actually want to learn-its very refreshing when that happens

Those old dogs that don't want to learn new tricks will sooner than later be down the road or on the bench. It's not the way it used to be anymore, the big companies are Crap canning the older guys that refuse to or cannot learn the newer equipment. They have this false sense of security that somehow seniority will protect them. At least that's the norm out here in L.A. Our union reps cannot do a thing about it because the guys cannot do their job. I completely understand that not everyone can be expected to reach troubleshooter/adjuster level, but yet we all call ourselves elevator mechanics. Expected to be capable of performing all aspects of the trade. Can you stack a set of 80 story rails? Install an escalator? Set a geared machine motor within .001", or plumb a 60ft. jack? We should all be able to fill all these roles. The 70% grade needed to pass our neiep training is embarrassing. I can count on less than one hand how many people I've meet over almost 20 yrs that can do almost anything. That old thinking that there's a place for everyone is a slippery slope we are plummeting down. That is exactly the reasons the company's give when it comes to contract time. "These guys are mechanics getting paid an $80/hr rate that cannot do the job they are hired for." We need more extensive training, and it's got to kept up to date with new industry technology. Period. At least if we expect to keep getting out international contacts signed.

Believe me, there are all sorts of unemployed people looking to cash in on a six figure salary. I doubt very highly that those requests would go unfilled. It just won't be filed by our brothers unless we help each other and strive to be better instead of sitting back and calling the adjuster.

this started out ok. a question was asked, then another question that showed a little lack of knowledge. some brothers are being used in construction, and heavy service work, and then being put in the maintenance callout rotation, whether voluntarily or by command. we really don't know. then it became a dialog about NEIEP, meters, lack of schooling, etc. and the man still doesn't have an answer. a question about blowing fuses can not really have a definitive answer, only advice, conjecture and supposition based on our experience. some advice was given, lets let this question rest in peace.

Thank You john jay! Some people having nothing better to do than bad mouth a brother. Nobody mentioned other than fuses, relays, and rectifiers that's all that is replaceable on this board. I don't know about LA, but I'm quite capable of removing and replacing any diode that I find bad but who does that anymore? This was the customers problem and I'll just order a new board! I'm not the type to just start throwing parts at something, but why did my question go here? I know the clc battery was corroded when I looked at it Friday and the power has been off since, so I know I'll need to reenter parameters and do hoisteay scan at least. Take it from there.

I hope that you are an elevator technician. I had a similar situation, blowing F2 fuse. Try taking out the relays labelled A1 and A2 the only control the gongs and direction arrows. Took me a bit to find this one. I really hope that their is no personal liability giving advice on this forum! Since this is not a safety issue, give it a try. Anyone else concerned about liability giving advice?

i make a s&it ton of money form the new guy going on calls and shutting down elevators, telling the boss what is wrong and then i go in a fix it the next day. my biggest issue is the RUSH RUSH that the office push with all the safety BS!!! you CAN NOT do both and the new guy are taking WAY TO MANY CHANCES.. the are going to kill themselves or someone else. the numbers don't lie look at the increase of accidents that have happened and the decrease of man power, even the old timers are slipping up and getting hurt because they are job scared & trying to get visits in and procedures done and trouble calls and, and, and, and, need i keep going?
The new guy's; you can't even call them up to try to explain what they might want to look for in the future, because there is know way i know more them they do.
back to the main issue if you don't know how to use a DMM to check a diode then you have any business troubleshooting ANYTHING! Its pretty basic! and i don't replace diodes i don't even know where to order them from anymore(zap?). no time anyways, but i do have a solder gun and a solder sucker just in case!!!!!

I do know how to use a DMM! By the way who the hell calls it that any way. Why the hell has this post gotten to this. I have a solder gun and wick and sucker too. I also know where to get diodes if I wanted to replace them (Digikey)!! To up date all you know it alls it is not a diode on the relay board, nor is it a rectifier or the capacitor. I have narrowed it down to the P24 going to the car. I have not yet isolated it from where it changes from P24 to P24C in the car station. I'm going to order a clc board as soon as the customer signs a open order.