Melcom St6100 - Rewire Or Replace Tomorrow?

[arfur mo]

Flux in electronic no-clean solder doesn't cause corrosion. NASA are fine with it, so am I.

possibly why Apollo 13 cane to grief.

NASA would likely not allow any form of humidity or damp, but trust me flux will corrode thin copper, it can cause 'dry joints' if to much is applied, or where the tinning is compromised.

[Simon K]

if you have bad connections (as it indicates to me) replacing the controls is an expensive fit and hope to cure option and not guaranteed to fix it, its more of a clumsy 'grape shot' approach, no diagnostics undertaken.

it could be likened to replacing your aged car engine due to crunching gears, you fit a new clutch because thats sensible and that was the real fault, the new engine was not the real cure but will seem it from the 'evidence' of success.

if you do replace and all is well, likely you have remade the bad connections in the process, it is not proof positive that your original panel was faulty.

A competent experienced alarm service engineer would soon assess, test and zero in, having trusted test methods to track down the real causes of the faults.

by all means get a new panel for later design innovations, but you could remove all zones and tampers, fit links (or resistors) in place then see if the panel mis behaves over a period, and what i would recommend short if engaging an alarm co.

 

So, I "sort of" agree with you that it's not necessarily a problem with the panel.  What I could do at this point would be to rip the panel out and perform all of the connections again from scratch, carefully and tidly, so that I am 100% sure that the job is done correctly.  However...if I'm going to do that anyway, why not change the panel for a new fresh one?  It's a relatively inexpensive part at £50 including remote keypad, and it *has* caused problems - even when it was working, there were times when it seemed to "hang" and needed to be reset.

 

As for getting an alarm company to do it - I did phone around, but I couldn't find anyone who would be willing to come in and work on it.  Everyone I spoke to basically said that they'd need to rip everything out - including the wiring and detectors and bellbox - and put in their own kit.  When I say the wiring isn't changeable (if you can convince my wife to let you redo the walls more power to you), they fall back on Wireless, which isn't acceptable to me.  If you know of anyone able to do a decent job in Sudbury (on the border of Wembley and Harrow - not the one in Suffolk) at a reasonable price then please do pass on their contact details )

 

-simon

[arfur mo]

So, I "sort of" agree with you that it's not necessarily a problem with the panel. What I could do at this point would be to rip the panel out and perform all of the connections again from scratch, carefully and tidly, so that I am 100% sure that the job is done correctly. However...if I'm going to do that anyway, why not change the panel for a new fresh one? It's a relatively inexpensive part at £50 including remote keypad, and it *has* caused problems - even when it was working, there were times when it seemed to "hang" and needed to be reset.

As for getting an alarm company to do it - I did phone around, but I couldn't find anyone who would be willing to come in and work on it. Everyone I spoke to basically said that they'd need to rip everything out - including the wiring and detectors and bellbox - and put in their own kit. When I say the wiring isn't changeable (if you can convince my wife to let you redo the walls more power to you), they fall back on Wireless, which isn't acceptable to me. If you know of anyone able to do a decent job in Sudbury (on the border of Wembley and Harrow - not the one in Suffolk) at a reasonable price then please do pass on their contact details )

-simon

the 'hanging' could be due to cable faults, shorts between one zone and another or the siren, and the panel software is often designed to freeze until acknowledged. This is so if your alarm activates while your out, and your not told. you could otherwise have several false alarms, annoying neighbours and lowering the perception of effectiveness.

perhaps you can partly see why your approach is flawed, i'm not bullying you but trying to save you money.

likely your system was a DIY or a 'sparky special', with respect to proper sparks, we deal in very low voltages and currents. a dodgy wire in a light fitting might well weald itself due to the arcing - or cause a fire, alarm kit don't offer that 'self healing' aspect.

the up side is CAT5e is marginally more robust than softer stranded alarm cable against damage under crushing or misuse when pulling in. i would not be put off by your cable.

you say wireless not acceptable? just like cabling knowing the kit and what your doing is key, just about any fool can stick an alarm system in, but as you have found out (thanks to someone else), what do you do if it is not reliable?

people bang on about interference and false alarms, its usually those who are already biased against or do not have the diagnostic skills and experience. think of it this way, if you change a suspect detector your effectively replacing the 'cable'. with wired, you replace a detector, the fault could be that, or the cable, or the connections, or damage.

To get a cable to the far end of a flat roof extension neatly is time consuming so expensive, so it go's near end to reduce cost and cable being seen. wireless you can put them where they serve best with no compromises, and you can cover outbuildings far easier.

[james.wilson]

Oh wow, thank you for catching that. Confirmed from the engineers manual: "These outputs are not applicable to the Optima compact panel". You just saved me from making a horrid mistake, really appreciate it ).

So now choosing between the "Mini":

http://www.securitywarehouse.co.uk/catalog/index.php?main_page=product_info&products_id=864

and the "Poly":

http://www.securitywarehouse.co.uk/catalog/index.php?main_page=product_info&products_id=1468

Are the "Mini" and the "Poly" identical except for size? Does the "Poly" simply have more space inside (making it possibly easier to work with)?

-simon

all the accenta boards are the same, there are 3 different boxes, mini, poly and metal. Mini is very tight on space inside and will only allow a tiny battery

[MrHappy]

(if you can convince my wife to let you redo the walls more power to you),

any reason why a wired alarm requires the walls redoing ?

[Simon K]

any reason why a wired alarm requires the walls redoing ?

 

The locations of the detectors mean that, if we wanted to change the cables, we'd need to cut through the plaster and make good afterwards.

 

all the accenta boards are the same, there are 3 different boxes, mini, poly and metal. Mini is very tight on space inside and will only allow a tiny battery

 

Perfect, thanks - will go for the poly then, £10 extra but not so tight will make for easier working (and a proper battery too).

 

you say wireless not acceptable? just like cabling knowing the kit and what your doing is key, just about any fool can stick an alarm system in, but as you have found out (thanks to someone else), what do you do if it is not reliable?

people bang on about interference and false alarms, its usually those who are already biased against or do not have the diagnostic skills and experience. think of it this way, if you change a suspect detector your effectively replacing the 'cable'. with wired, you replace a detector, the fault could be that, or the cable, or the connections, or damage.

To get a cable to the far end of a flat roof extension neatly is time consuming so expensive, so it go's near end to reduce cost and cable being seen. wireless you can put them where they serve best with no compromises, and you can cover outbuildings far easier.

 

Sorry, wireless isn't acceptable for me personally.  Firstly, I don't want to risk RFI, I have enough problems with local sources of RFI; even when running my radios entirely from a bank of batteries I pick up the most horrific interference.  That, plus I don't on principle believe that the wireless protocols used are likely to be really secure - not that I'm expecting that sophisticated a burglar to attack my property, but I can easily imagine some time from now a crimminal gang reverse-engineering the security of common brands of wireless alarms and providing burglars with simple boxes to press to deactivate.  Wired or nothing for me )

[Simon K]

the 'hanging' could be due to cable faults, shorts between one zone and another or the siren, and the panel software is often designed to freeze until acknowledged. This is so if your alarm activates while your out, and your not told. you could otherwise have several false alarms, annoying neighbours and lowering the perception of effectiveness.

perhaps you can partly see why your approach is flawed, i'm not bullying you but trying to save you money.

likely your system was a DIY or a 'sparky special', with respect to proper sparks, we deal in very low voltages and currents. a dodgy wire in a light fitting might well weald itself due to the arcing - or cause a fire, alarm kit don't offer that 'self healing' aspect.

the up side is CAT5e is marginally more robust than softer stranded alarm cable against damage under crushing or misuse when pulling in. i would not be put off by your cable.

 

Indeed, I'm sure that you're correct.  I'm going to have to fix the cabling and do it properly.  It's quite a big investment of time and effort for me (I'm sure for you guys it's no more than an hour or two work, it'll probably take me the best part of a day), so I'm going to make sure that I only have to do it once )

 

Once I take the box off, I plan to disconnect all of the detectors and check the all of the cables individually (I have a Fluke 87-V and will look for a cable resistance of about 100mOhms/metre as per cat5e specs).  The detectors are dual microwave/PIR, I believe they're probably OK; I'll only change the panel for now.  If I do have a cable run which is bad...I'll probably come crying on here for help or something ;-).  Maybe if there are at least a couple of good pairs I can play with things like shorting the tamper at the panel side rather than connecting it up to the detector.  I don't know, we'll see.

[arfur mo]

To test cables,

Disconnect both ends, test between cores and ti a good earth on hi res.

Now short all cores at detector end, on lowest ohms range use say orange as your reference core, test from controls end to remaining cores and note resistance's, all should be the same. finally test w of range to w of green (to prove orange is also ok).

[MrHappy]

The locations of the detectors mean that, if we wanted to change the cables, we'd need to cut through the plaster and make good afterwards.

chasing walls to fit detectors...

what type of detector & where is it being fitted ?

[arfur mo]

tbh as you do have cable issues and at least can understand resistor arrays, i really would go with a panel that uses DOEL cable monitoring.

your current panel is likely 'double pole', likely uses a single closed loop for each zones positive sensor loop and a 'universal' tamper sent around all the detection ti act as the double pole

fine if no problems but only responds during the time it is armed, where as DOEL monitors the alarm circuits 24/7, which includes the separate tamper on each zone. less affected by small intermittent until they get big enough go be a real problem and then are much easier to 'see' on which zone and on a meter.

Risco Gardtec CPX will do 8 zones out if he box, and has a built in VoCom dialler for simple alert warnings to your phone.