Author Topic: Calling all Elec Engineers and Electricians therof  (Read 929 times)

Calling all Elec Engineers and Electricians therof
« on: October 01, 2019, 03:43:32 pm »
Next Door Neighbours (both disabled) have an external intercom which is connected to internal separate phone which can also open the gate

Exhibit a) External Intercom 

Exhibit b) Wiring of external intercom

Exhibit c) Internal phone

Exhibit d) Inter wiring of the phone

Currently the intercom button and on the external intercom and phone is dead and the door release mechanism on the internal phone is dead button marked with a key

I have contacted Videx the manufacturer and they indicated;

Have you checked the voltages at the handset as per the guide? You should see the following (measured against 3):

Connection         Voltages
1                              12V DC (on hook)             4V DC (off hook)               0V DC (lock button pressed)       
2                              12V DC (on hook)             ~0.8V DC (off hook)       
4                              4-12V DC (call button held)

If any of these are missing then do the same checks at the 836M, 4 from the handset should be connected to P1 at the door panel.

You can also test the release function of the 836M by putting a short between 1 and 3 to simulate pressing the button on the handset, if this works then the fault is with the cabling to the handset (likely as you also don’t have the speech) or a fault with the button in the handset, if it doesn’t work then short S to – to test the wiring.

If a single wire is down then it will be terminal 3 as this is the common negative side of everything in the handset so if this wire is not connected then the handset would be dead.

Wiring Guide



There is power to the external intercom but there is no speech nor can the gate be released from the phone internally

Couple are reluctant to call in the experts as a £££££££ awaits---so any ideas greatly appreciated--assume noddy knowledge on on part re electrics

many thanks for any guidance

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: Calling all Elec Engineers and Electricians therof
« Reply #1 on: October 01, 2019, 03:48:16 pm »
What are you asking?

Re: Calling all Elec Engineers and Electricians therof
« Reply #2 on: October 01, 2019, 04:03:53 pm »
how do I check the voltages

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: Calling all Elec Engineers and Electricians therof
« Reply #3 on: October 01, 2019, 04:09:38 pm »
I'd be more inclined to help you for free if you bothered to punctuate properly.  That last post was a question, right?  Try putting a question mark at the end. 

After that, step 1 is to buy a voltmeter.  Something like this.

Re: Calling all Elec Engineers and Electricians therof
« Reply #4 on: October 01, 2019, 10:30:23 pm »
you need a voltmeter. Most come with basic instructions so that if you have never used one before you might not cause more problems than you solve with it.

The instructions seem pretty clear to me; clear that is for anyone who has the slightest grasp of how you might use a voltmeter.  I'd suggest that you practice using the voltmeter on other things (eg loose batteries) before testing anything that might be expensive to replace.


  Is anything working?   If so this ought to give you clues too.

cheers

Re: Calling all Elec Engineers and Electricians therof
« Reply #5 on: October 01, 2019, 10:35:56 pm »
You need to connect the voltmeter between wire 3 (GND/Negative/0V) and whichever of the other three wires you want to measure.

Kim

  • Timelord
Re: Calling all Elec Engineers and Electricians therof
« Reply #6 on: October 01, 2019, 11:09:21 pm »
Free piece of advice for multimeter newbies: You want the probe leads in the common/ground and volts/ohms/hertz/etc sockets for measuring voltage.  You *don't* want one in the amps socket, because as soon as you connect that to a voltage source you'll either blow a fuse (on decent meters), break your multimeter (on cheap ones), and/or let the magic smoke out of whatever it is you're testing.

If you do blow the meter's fuse, the main symptom is that everything you try to test reads zero (or open circuit on the resistance ranges), which adds to the confusion when troubleshooting things.

(Much like clipless moments, this is the sort of thing that's more likely to catch you once you've got the hang of what you're doing with the meter, after you've successfully used the current range for something and forgotten to return the leads to the usual place.)
Careful, Kim. Your sarcasm's showing...

barakta

  • Bastard lovechild of Yomiko Readman and Johnny 5
Re: Calling all Elec Engineers and Electricians therof
« Reply #7 on: October 01, 2019, 11:26:59 pm »
Another thought is putting out a call on any local groups for people who speak electronics to help you. Nottingham has a hackspace which might have a twitter for example. Geeks are often happy to help in exchange for BEER or similar...

Re: Calling all Elec Engineers and Electricians therof
« Reply #8 on: October 02, 2019, 12:00:02 am »
Actually, before you crack out the voltmeter, I'd start by checking the obvious physical things - are all the wires connected and the screws tight? Is there any damage to the wiring?

I'd also follow their suggestion of shorting out terminals 1 and 3 with something metallic and seeing if the gate releases. You can try this at both the external panel end (the connections at the bottom!) and the handset end.

(You said there's power to the outside panel. Is the doorbell function working?)

Kim

  • Timelord
Re: Calling all Elec Engineers and Electricians therof
« Reply #9 on: October 02, 2019, 12:38:04 am »
Actually, before you crack out the voltmeter, I'd start by checking the obvious physical things - are all the wires connected and the screws tight? Is there any damage to the wiring?

Yep.  Other things readily detected with a Mk 1 eyeball include:
Signs of water ingress.
Corroded switch contacts.
Obvious scorch marks / anything that smells burnt.
Bulging electrolytic capacitors[1].
Crappy solder joints.

Things I'd be immediately suspicious of would be the wiring and the power supply, which is where you start poking about with a meter.  Note that a common failure mode of power supplies is that they supply the right voltage until more heavily loaded, when they drop out.  So you might have some power, but not enough to drive the solenoid, for example.


[1] Components like the one marked C3 in the internal phone photo.  Common failure mode is for the electrolyte within them to overheat and produce gas, causing the metal case to visibly bulge (and the electrical properties to deteriorate, but not always to the point of total non-functionality).  The two in the photo look okay.
Careful, Kim. Your sarcasm's showing...

Re: Calling all Elec Engineers and Electricians therof
« Reply #10 on: October 02, 2019, 06:34:54 pm »
Thanks for you input everyone greatly appreciated.

Answering specific questions as best as I can, Kim I have done an eyeball check on the things you mentioned  and everything looks ok wire wise please attached. Also see the Multi Meter are the plugs correct? ie in the right position/many thanks



Grams please see above though I noticed the indoor phone takes its power from the gate mechanism and then that goes to main. For shorting the wired do I just take the wires out of their current placement and wrap them around a piece of metal to short them?



The gate does have power going to it Name plate lights are on  see the attached below and the buttons seen below 1-23 etc are all working the only thing on this panel not working is the intercom button next to the name plate




Brucey there is power to the external keyboard on the post next to the gate but the intercomm button next to the orange lights is dead and so is the internal phone which answers the intercomm

Thanks again everyone for all your support



Kim

  • Timelord
Re: Calling all Elec Engineers and Electricians therof
« Reply #11 on: October 02, 2019, 07:21:05 pm »
Thanks for you input everyone greatly appreciated.

Answering specific questions as best as I can, Kim I have done an eyeball check on the things you mentioned  and everything looks ok wire wise please attached. Also see the Multi Meter are the plugs correct? ie in the right position/many thanks

That's the right sockets, though you've got the selector knob in the AC voltage range.  That might be right for measuring the power input if the system is fed by an AC power supply (the markings on the terminals suggest it will accept either AC or DC), but for the other stuff, you'll need the DC volts range anticlockwise of the 'off' position.  Getting this wrong is harmless, though - nothing will break, you'll just see is zero if you try to measure AC with the DC range, or vice-versa.

In case it's not obvious, the various numbers denote the tradeoff between maximum measurable value and degree of precision:  If you probe a 1.5V AA battery in the 200V or 600V range, it'll probably just display "1".  In the 20V range you might get "1.4", if you use the 2V range, you might get "1.48", and if you use the 200mV range you'll get "-.--" or "OFL" or something, to indicate that it's off the scale.  If you connect the positive lead to the negative terminal (and vice-versa) of a DC voltage source, you'll just get a negative reading.  AC doesn't care about polarity.

The resistance (Ω) range can be used to test for continuity (to see if wires are broken or whatever):  Use the 200Ω range, and see what happens when you touch the probes together.  It should read some very low value (the resistance of the probe leads themselves, probably an ohm or two), and if you're lucky, the meter will make an annoying beep, saving you from having to look at the display when testing wires etc.  Don't use this to test things while they're powered up.
Careful, Kim. Your sarcasm's showing...

Re: Calling all Elec Engineers and Electricians therof
« Reply #12 on: October 02, 2019, 09:33:51 pm »
I agree it makes sense to open the covers and check for the obvious loose wires, blown fuses, other easy fixes.

Having not found any, and without the expertise for full diagnostics and repair I think spending the £££ for a qualified expert should be the next step.

Okay it may not be cheap, although it may also not be as expensive as you envisage - an engineer familiar with the system can probably isolate the fault and repair it fairly quickly.

Your post suggests it's really important for the system to working properly for your neighbours, so they can let people into the property. In which case spending a few pounds to have the reassurance it is in working order would, for me, be money well spent.


Re: Calling all Elec Engineers and Electricians therof
« Reply #13 on: October 02, 2019, 11:37:02 pm »
The resistance (Ω) range can be used to test for continuity (to see if wires are broken or whatever):  Use the 200Ω range, and see what happens when you touch the probes together.  It should read some very low value (the resistance of the probe leads themselves, probably an ohm or two), and if you're lucky, the meter will make an annoying beep, saving you from having to look at the display when testing wires etc.  Don't use this to test things while they're powered up.
If you turn the meter to the diode test range (the orange arrowish symbol between the 200 Ω  range and the 10 A range, one click anticlockwise of straight down), you might get the annoying beep when you touch the probes together, even if the 200 Ω range doesn't beep. The diode test range, like the 200 Ω range, will test continuity, and also shouldn't be used on circuits when powered.
Quote from: Kim
Paging Diver300.  Diver300 to the GSM Trimphone, please...

Kim

  • Timelord
Re: Calling all Elec Engineers and Electricians therof
« Reply #14 on: October 02, 2019, 11:51:55 pm »
If you turn the meter to the diode test range (the orange arrowish symbol between the 200 Ω  range and the 10 A range, one click anticlockwise of straight down), you might get the annoying beep when you touch the probes together

I've learned a thing.

Of the five meters I have to hand, one does this (but not as responsively as it does in the continuity mode[1]), two only beep in continuity mode, one doesn't seem to be working properly in the diode test mode (suspect flat battery, I rarely use it), and one (of the 2-for-a-fiver from Craplin variety) doesn't have any beep capability at all.


[1] This one also has a lovely inverse-continuity mode, where it beeps when the circuit opens.  Best used with croc clips so you can wiggle things systematically to look for intermittent cable faults.
Careful, Kim. Your sarcasm's showing...

Re: Calling all Elec Engineers and Electricians therof
« Reply #15 on: October 07, 2019, 04:11:39 pm »
Thanks everyone for all your inputs very much appreciated. 2 wires were dead.