Home Forums General Discussion Technical Questions New DMC Issue

This must be the month for DMC problems. I have a DMC that will fail every two to four days. When it fails the car will run floor to floor and not open its doors. Half the time it creates an occupied and the building shuts it off before we get there. I was able to plug in the world tool on the last failure and this was my finding: there were no faults on any subsystem (CLC, Selector, front door) and all subsystems were present. However, when I went to view a parameter all parameters were blank on all subsystems. I began to unplug one board at a time to isolate a possible bad board but none restored my parameter tables. Only a full power shut down would reset the car and all parameters would be restored until the next failure. So far, I've changed the power supply and CLC board. Anyone seen this type of failure before?

when you say, you had no parameters, do you mean: You could not access the parameters or that the parameters were all blank or set to 0. After you dis a MLR, when you got back the parameters, were there any faults in the sub-systems. Just off the top of my head, it seems that you have a comm fault. Did you try the tool at any pont other than the Machine room? If you hook directly to the door operator, you should be able to see door faults even with a comm error. I used to fix a lot of intermittent faults by taking two 1/16" punches and going through the COP multiplugs at the top of the COP. Insert one from the front and one from the back and push. Of course, you need to TURN OFF THE EQUIPMENT before as there is 150VDC and 120vac in these connectors. Your comm runs through these connectors for the selector and the door operator.

Car lighting does not go through these connectors, so you can leave the car lights on and not have to work in the dark.

When the elevator would fail, all of the parameters would go blank in all subsystems. It wouldn't show defaults or 0s the parameters tables are just blank. The weird part about it is the elevator would continue to run and answer hall calls and car calls it just wouldn't open the doors. After a MLR there are no faults displayed and all the parameters will restore to their original values. I thought about going through all the COP connectors but usually when I have a comm error it will show the board Absent on the tool. I've never seen one fail in this manner before. I need to try and get it to fail again while I'm there to plug into each board directly to gather further information. What do you think about changing the CLC software?

world tool is not a very good one to use on DMC, some version of software will not display the parameter correctly. Use Fast tool or IMS. I agree with johnny, check the connection on your door board.

I just had a pretty similar problem recently. When I arrived the car would answer calls but had no door operation... When I tried operating the doors from the HD85 open and close buttons I had nothing. Plugged my tool into the HD85 board and didn't even turn the tool on, and tried the open and close buttons and they started working?? Ordered a new HD85 board but haven't had a chance to change yet but car has been running for a week. Apparently the building was doing some generator work that morning and the building power was being affected. I'm pretty sure it's going to end up being the HD85 board going out but not 100%.

Im lucky to have a fast tool i guess, does this world electronic tool let you go from CLC to fast and fast to CLC?

My DMCs on my route start doing wild things when the power supply goes south. But you covered that base.

I'm tearing some DMC stuff out right now, putting in MCE M2000s. . Feels so good! It was pretty flakey stuff.

Sorry for such a pointless post. But it's hard to contain my joy!

Take the switch tree off the side of the car.very easy, 2 bolts and it lifts out you can lay it on the cartop. Have seen broken and pinched wires, that create very strange problems. I love the DMC units, think they are very robust if you change the battery behind the COP every year. I have the DMC software and its easy to use and very helpful. Wish Dover was still in business.

Ive had a similar problem in the past that drove me nuts. I changed all the boards one at a time still had issues with not seeing parameters and pulled my hair out. After talking to a Dover adjuster he said there are 6-8 relays in the controller that need to be changed every years or so. The back contacts were worn out and as soon as I changed these relays my problems went away. Sorry I dont have the sheet that he gave me with the list of relays to change but at least its a start.

I can't see how a worn relay could cause the parameters to not be seen. They are in no way involved in the software. If you were using a world tool on an early version dmc, the parameters will not show or be blank. I'm going to assume when you replaced the cpu that the updated software and new eeprom solved your issue. Eeproms have a definite lifespan, and when that time draws near, software will do weird stuff.

I had this very problem it was a faulty 3 pole toggle switch at the bottom of car station I think door power supply goes through switch.I have seen many switches removed and wires just wire nutted together

Yeah at that point p24 turns in p24c on the print

also p24 turns to p24g on one of the poles. that 3 pole switch has caused alot of prolems for elevator guys. turn off the switch, to check something, and when you turn it back on, you have more problems then when you started. the administrators problem turned out to be the door board. I have a similiar problem on a dmc, if you turn off the mainline, and turn back on, the car will run fine but not open the doors, you have to get to the door board and press the reset button, the all is fine. still need to change that door board. strange problem, you would think cycling the power would reset the door, but it does not, it will only come back on line with a push of the reset switch.

Sorry for not responding with the fix for this problem. Indeed it was the door board that took care of this issue. Very weird the door board failing would cause all the parameters to show blank on all the other sub systems even though they showed present on the World Tool. I guess it's just another learning lesson to not over think the problem and go with the obvious symptom (the door not opening). Anyway, I'll know better next time. Thanks for all the suggestions guys......

Hey Scott,

That problem you are having with the door board with a main line reset or power failure is pretty easy to fix. I would guess that you or someone else has installed a Pana40 or an Fcu 47 as an upgrade. When the power is lost on a lot of older DMC'S the scanners can cause some 'electronic chatter' disrupting the boot sequence of the door board. A simple fix is installing an 'on delay' timer to prevent the scanner from turning on with the door board all at once. Usually about a two second delay is suffiecnt. You want the door board to finish booting before your scanner turns on. Weird problem I know but I would bet money this is the issue.

very strange, i was at the job to service today, this time i put the car on inspection at the top floor, anticipating having to press the door reset button after shutting the unit down to service. to my surprise, when i turned on the power and went to inspect car down, i decided to just turn on normal, and the doors operated fine. so i checked again, shut off power with out putting on inspect and sure enough had to press reset button to get doors to work. any way did not have time to deal with it today, it is only a 2 stop, and does not get used that much so maybe next month i will delve into the problem a little further. thanks for the info, i will look into it.