Kam DJ250 Colour Changer fault

[fbnts]

Hi,

 

I have 5 Kam DJ250 Colour Changers (24v ELC lamp type).

 

3 of them have failed over the last week, all with a similar faults.

 

On power-on they would normally reset all stepper motors and the LED screen on back would show "----" however these three no longer display anything on LED screen and the stepper motors just hold (they dont move but have tension on wheels). I am pretty sure its the Flash chip as I have an old board with a slightly different fault and when I put that Flash chip into the faulty ones they work, other than the same fault.

 

Does anyone know a source for the chips programmed up or does anyone have experience with In System Programming (ISP) to read a working chip and re-flash a blank one?

 

The chips are NXP P89V51RB2FN.

 

Tom

[KevinE]

That is an 80C51 microcontroller with Flash rom and user ram.

 

You are best getting that from Lamba themselves, they own the KAM branding.

 

Lamba PLC 01582 690600

[fbnts]

Thanks for the quick reply. Yeah I have been on the phone with their service department today however as its an old product he has got to see what stock they have (Can only get the main board with the Flash on) thats why I was looking at programming blank chips up as the chips are only £2.50 from Farnell.

 

I'll see what they come back with tomorrow otherwise is it easy-ish to copy the existing one?

 

Is there anyway to debug the microcontroller to see exactly where its failing? Also, could there be any explaination why all three have gone in such a short space of time?

 

Tom

[DrV]

I'll see what they come back with tomorrow otherwise is it easy-ish to copy the existing one?

 

Sorry to bear negative news but you'll probably find that the code is not readable from a good chip. Most manufacturers understandably program the protection bit in microcontrollers to prevent people from copying their code and bypassing all their expensive man-hours of code development.

 

Dave

[fbnts]

Yep I hear you on the protection - I just need to pray that Lamba have a few spare boards kicking around else it means new fixtures :-)

[fbnts]

It would appear there may be something more sinister going on or just a fluke misfortune but over the last week 4 fixtures have died, two amps and now the Ohm Cleo Speaker management/crossover.

 

All equipment are different circuits but could there be some sort of power fault that could cause this? Has anyone had a similar issue before?

 

The building is fed by a 3 phase incomer which we had to call Central Networks out a few weeks ago as pitch was leaking from the cut-out. They cleaned out the excess pitch and checked the connections which needed tightening up a little. Could it be some weird phase fault and if so whats the best way to measure it?

 

Tom

[Brian]

Could it be some weird phase fault and if so whats the best way to measure it?

Yes. You'll need a Power Quality Analyser/Logger; or phone your electricity supplier and complain.

[KevinE]

Possibly a loose or overheating neutral, this may cause overvoltages at final circuits.

 

I use an example I've quoted before which is perfectly true, which is that one of our customers as tenants at the former GEC Ceramics works were using banks of electric kilns, and developed burned connections at various points in their 1950's LV distribution system. Coupled with an untrained guy wiring equipment using the mains earth as a neutral where no neutrals were provided, they decided to call in the experts when an employee plugged in his kettle and blew an electric clock off the wall.

 

The contractors found a corroded neutral in a distboard that had been taking in water.

;)

[fbnts]

Ah oh, that could be a start - The incoming is in the pub cellar and is fed from through the wall behind. Behind the wall is an access tunnel which belongs to the Electric Board. it carries all the LV mains from the substation behind the property out to the streets in front.

 

About 3 weeks ago some water started pouring from out the access tunnel (theres a locked door from our cellar into this tunnel) I phoned Central Networks but unless it posed a danger to our meter they wouldn't come out.

 

The whole electrical installation in the property is relatively new (around 5 years old) only the incoming cable and cast iron cut-out are old. The cut out is still leaking pitch, mainly at night when we are open as we are pulling over 80amps (I have an owl energy meter). I will call Central Networks and see what they say.

 

Also, I have used the energy meter to measure approximate load on each phase. This afternoon they were:

L1 - 9.4 KW

L2 - 4.8 KW

L3 - 3.4 KW

 

I will measure tonight as I think most of the amps etc are on L3.

 

Could this imbalance cause any significant problem?

[DrV]

Also, I have used the energy meter to measure approximate load on each phase. This afternoon they were:

L1 - 9.4 KW

L2 - 4.8 KW

L3 - 3.4 KW

 

I will measure tonight as I think most of the amps etc are on L3.

 

Could this imbalance cause any significant problem?

 

Of itself the imbalance shouldn't cause a problem - the neutral wire is there to take the balancing current. But if there is another problem such as the dodgy neutral already mentioned this may well cause overvoltages in the final circuits. The fact that the service head is getting warm enough to soften the pitch is REALLY worrying. Your supplier absolutely must get to the bottom of that one!

 

Dave

[fbnts]

Thanks for your replies. I'm going to get in touch with Central Networks and ask them to look into it and possibly an electrician. Just took some measurements with a clamp meter whilst open with everything running and got the following results:

 

L1 - 74.9 Amps

L2 - 27.7 Amps

L3 - 20.1 Amps

N - 49.9 Amps

 

If there were a neutral fault similar to the scenario above I presume the phase with the highest load would have the higher voltage or would it be the one with the lowest load?

 

Would I be able to measure the voltage at the end of the circuit or would the higher voltage just occasionally spike?

[DrV]

Thanks for your replies. I'm going to get in touch with Central Networks and ask them to look into it and possibly an electrician. Just took some measurements with a clamp meter whilst open with everything running and got the following results:

 

L1 - 74.9 Amps

L2 - 27.7 Amps

L3 - 20.1 Amps

N - 49.9 Amps

 

If there were a neutral fault similar to the scenario above I presume the phase with the highest load would have the higher voltage or would it be the one with the lowest load?

 

Would I be able to measure the voltage at the end of the circuit or would the higher voltage just occasionally spike?

 

The phase with the lowest load would be the highest voltage. You might see it with a meter but not necessarily. You would get big spikes (which you wouldn't see with a meter) each time a large motor such as an aircon unit or a lift etc. started up.

 

Dave

[fbnts]

That would make sense as the majority of the equipment that has failed are on L3. Also the bulbs in the fixtures have been blowing very quickly (24v 250w halogen should last 50 hours, some are lasting 5!)

[KevinE]

Get it sorted before the cutout flashes over and catches fire

[fbnts]

Just an update - I have Central Networks onsite now. They have ruled out a neutral fault but have found that the Loop Impedance for Phase 3 is high and they are now looking at rejointing the cable and have also identifed a fault in the substation behind the property.