bigclive

Can you think of a reason why the two designs couldn't be combined? If you had nothing on the two red LEDs, that could either mean no signal being received at all, or lost ground, but the bi-colour LED would show the presence of the differential signal.

 

In the event of an open data line the bi-colour LED would potentially couple enough current across from the good data line to the open circuit line to make its LED look active.

At the risk of spamming the forum with one of my own videos, I find a tester like this incredibly useful on large DMX installations, and much simpler and cheaper than TDR testing.

 

 

 

Moderation: link fixed

I've been saying this for years, and have spoken to several DJs I know about this increasingly risky practice - though sadly with most of them the conversation fell on deaf ears.

I just make sure that wherever possible if I'm at an event where the DJ has one me and mine are sitting out of the field and my family in particular are wary of the dangers...

 

Yup. If I'm at an event where a laser is being indiscriminately fired at eye height then I'll intuitively avoid eye contact and warn others with me to avoid it too.

 

Have you considered doing a "serious face on" video about this subject. I know more people will come across the information on YouTube than here, and if even a handful of the idiots actually pay attention it can only be a good thing.

 

I've had numerous arguments with mobile DJs over the years about lasers, and they all seem to be under the impression that they wouldn't be able to buy it they were dangerous, and that all the rules about laser exposure (some of them have actually heard of them) are only for the big stuff like you see on TV. They simply don't believe they're putting people at risk.

 

I am considering making a video describing what the person experienced. I may even try to get the unit that caused the eye damage.

A friend has just suffered permanent retinal damage from a laser. Not some big show laser, but a humble Xmas laser starfield projector.

The lasers were cutting in and out so he opened it and was checking for loose connections by wiggling connectors when the green laser came on as it was aligned with his eye.

 

He thought he'd just been dazzled, but when his vision in that eye remained blurry (with floater) for a couple of days he went to an eye specialist.

 

They told him that the retina is permanently damaged and it will get worse over the next few weeks as it heals.

 

It's left him with a dull patch in his vision and difficulty focussing on things.

 

A stark reminder that even small lasers can pose a significant eye damage risk. Something to keep in mind as clueless DJs blast higher and higher power disco lasers directly into crowds of people.

Any body know what fittings ikea uses to project onto the floor?

 

Think it`s Derksen, not at the budget end of architectural

 

https://www.derksen.de/en/

 

Looking at the street light version reminds me of when a contractor mounted some on Buchanan Street and taped the gobo to the front with insulation tape.

 

It didn't matter anyway. As with most architectural follies nobody ever changed the lamp in them when the first one failed.

Having repaired many totally destroyed curtain systems including ones where the curtains had been dragged forcibly through small holes and where winches had physically ripped themselves off their mountings I would strongly suggest a dead mans handle system that does require you to keep your finger on the button.

 

Although many systems do use a geared selector on the winch there are some with switches mounted on the track. Notable for the switches dangling off the track on the end of their cable. If this sounds like a bleak picture it's because Northern Light used to get called in after all the resident experts had finished dabbling. hence why I got to fix so many tab-tastrophies.

 

First thing worthy of note. There's no such thing as an "economical" motorised curtain system. Not unless you want the curtains to open erratically and very slowly with a loud whining noise and the sound of plastic gears crunching loudly. It takes a reasonable force to open a curtain smoothly and swiftly. That can be done with a human pulling a rope or a winch with a control system. One of those things is cheap and reliable, the other is expensive and will result in curtains stuck mid-position if it fails during a show.

 

Choosing the cheap reliable option (human powered) the best approach is to use a curtain track intended for roping. I'd suggest Hall's equipment if it's still available. Not cheap, but reliable and so tough that you could hang a politician from one of the bobbins. The options for roping could include a steel wire rope going to a hand operated crank or a simple textile rope with a weight on the end so it hangs down in a decisive manner. My own choice would be the hand pulled rope. Over enthusiastic cranking of a hand winch can result in a huge knotted wire-rope mess when it skips the drum, and also poses a finger trapping risk.

 

Now for some case examples of curtain failures.

 

Example one. A horrible old wooden bobbin track which had been greased. The grease had the classic WD40 effect of providing temporary respite from the issue of wear and dirt buildup, but then gathered all the dust in the vicinity and turned into a disgusting resinous goo that made opening the curtains manually almost impossible. Fortunately a small but powerful DC winch had been added, and it used brute force to drag the curtains open against the will of the coagulated grease.

Except it had this really annoying habit of blowing fuses. Not because of the strain it was under, but because the switches at the ends of the tracks were dangling off, meaning that it stalled forcibly but silently at the end of travel and the large transformer in the panel limited the current until the fuse blew.

That was, until one of the caretakers who had been shown how to change the fuse put in a bigger and therefore better fuse. The transformer then went up in smoke.

 

No problem, a local electrician came in and changed the transformer for a new one which then went up in smoke again.

 

Then we were called in. The repair involved removal of the worst of the grease from the tracks, the re-fitting of the limit switches and the replacement of the transformer and fuse. I also removed the latching function so someone has to stand there and hold the button to open and close the curtains. That way the motor won't be left in a stalled state again.

 

Example two. An event venue is being refurbished and their curtains stop working. The resident experts have a go and then Northern Light get called.

I turned up to find what had obviously been a phase reversal issue. But to fix the fact that the curtains were going in the wrong direction they had swapped all the wiring to the buttons in local and remote control positions. What they didn't realise was that the limits at the end of the tracks were now wrong. Then they swapped some more wires and one popped out and they didn't know where it went to they stuffed it down the back of the DIN rail out of sight and called NL.

 

A little bit of information about what had actually happened other than "It just stopped working" would have been useful. No drawing so I had to trace all the panel wiring including remote button stations. It quickly becomes apparent what had happened and I effectively have to re-build the panel. Once it's going I let them know it's working and got confirmation that the phase reversal issue had happened during refurbishment of the building. Then one of them said "Did you find the wire stuffed down the back?" Yes... yes I DID find the wire stuffed down the back.

 

In both these failures the curtains were rendered unusable until repaired.

You do get OSB with flame retarding properties, but not as standard.

Is it for small fixed sums? I wonder if the new tap-to-donate units might be of use?

I'd be very cautious about trying to provide remote training as opposed to being directly with the people being taught. It's important to be able to see that someone really does understand what you're saying. At the modern slideshow courses there are typically three types of attendee:-

 

1. People who interact and make comments that show an understanding of the subject being discussed.

2. People who make arrogant statements that show supreme confidence in their flawed electrical knowledge.

3. The quiet people who don't even understand the basics and are just going through the mill.

 

I attended one of James Eades presentations and compared to many other presentations it was actually very good. I'm not sure what his career history is, but I'm guessing it's less practically biased and more from a university electrical engineering direction. His involvement with the event industry seems to be similar to my own these days, with just a few events a year to keep my hand in. He does know his theory, and I really don't envy him the responsibility of being in the position of having to issue certification on the basis that some people could lose work without it, but may not have enough deep technical understanding to justify it.

 

Those people with a BS7909 certificate will then potentially be put under pressure to work on electrical equipment and fault scenarios they don't understand because they're "qualified".

On the topic of "tickets" being used as meal tickets for unscrupulous bodies and get-out clauses for dodgy employers, I agree with you but only where workers habitually use the equipment during their routine work. A scaffolder won't need a PASMA renewal, a house painter might. A lighting technician almost certainly would not but a teacher almost certainly would.

 

Scaffolders DO need to renew their many certifications repeatedly as do all other trades. And they go on the "courses" (slideshows) knowing that it's nothing more than an expensive racket. In almost all instances a single viewing of the slideshow would be enough. In this incidence it could have prevented that scaffold tipping incident.

 

Interesting to note that there's no mention of outriggers on that regulations excerpt. In the UK they do that box ticking thing by demanding they are used in all situations, even in tight locations where they can't physically be used.

And to think that by sending the teacher on a one-day PASMA course the school could have simply washed its hands of all responsibility and placed the blame firmly on the teacher.

 

Because that's how it seems to work these days apparently.

The weight of the material may also be an issue of it's being Kabuki dropped. Traditional stage blackout velvet is quite heavy.

 

Control of light will help a lot with traditional black materials as mentioned by the others.

It's also worth mentioning that if a lamp has been in a bad holder the pins will be pitted and it should not be reused in a good holder as it may start the arcing and pitting process in that one.

IATSE Local 190 here, formerly Secretary-Treasurer and currently recording secretary.

The Blue Room forums are not especially welcoming of we folks from the Colonies.

 

I wouldn't say not-welcoming. The blue room is more biased towards British theatre crew and staff. Although it's the same industry, our equipment and electrical systems have significant differences which makes it much more complex if someone asking a question doesn't mention that they're in a completely different country.

 

It's also worth mentioning that almost every theatre in the UK has an IATSE sticker in it somewhere.

I'd recommend sticking to an original power supply in the exact same format as the existing one. These units are space optimised to the hilt.

 

My own approach to repair would be to start by looking at the back of the PCB and probably reflowing the solder connections on the transformer.

For a simple repair approach with no test equipment I'd suggest swapping out those two big round capacitors next to the output connector. They will be low ESR capacitors. After that the prime suspects would be D1 and the round capacitor at the top right hand side of the PCB. All those components have to be installed in the correct polarity.

 

If not confident in electronic repairs then consider buying a new light and keeping this one as a source of spares.

There was talk of an alliance between the UK union BECTU and IATSE in the past, but the way the unions work is so different that it didn't happen.

Although IATSE refers to itself as an international union it's really primarily American.

 

I think the closest we have to IATSE here is the Combined Union.

That hiccup effect usually points to two areas. The electrolytic capacitors on the low voltage side (must be low ESR types) or the bootstrap circuit on the mains side. Check the solder connections on the transformer first and then look for a diode going from one of the primary side windings to a capacitor near the control chip. There may be a bad solder joint, diode or capacitor there.

If it's a small room try a pack of Durian flavoured cream wafers from your local Chinese store. They really do smell like a pungent gas leak.

It must take a lot of rain to fill a par can when the cooling air coming out is over 100c!

 

One of the advantages of a PARcan is that if you shield them from direct rain they are fairly resilient to moisture.

The main issue is if their ceramic lamp holder gets wet it passes current to the can via the lamp rotator. They normally keep themselves dry in use, but can be a bit irksome after a stormy night/day.

 

One of the significant job complexities of the Tattoo is the random Haar sea fog. It can deposit lots of water on every surface it touches. You could screw a bucket to the ceiling and it would be dripping with water inside. Add the risk of driving horizontal Scottish rain on the super-exposed hilltop location and it limits the type of fixture that can be used. Even the super-rugged PRG lights designed to tolerate extreme conditions have their moments on particularly violent days. That includes wind issues that stall cooling fan airflow, mess with domes and can apply enough wind pressure to the side of a light to stall its movement and make it lock-out.

 

We tested a load of new IP rated LED PARcan replacements this year. They weren't even remotely near the old tungsten ones. Very dim with a round splodgy splat of RGB white. Ideal for normal stages, but not for a large arena show presented in the round. Especially one where the lighting has to accommodate the BBC filming too.

 

The ill-conceived campaign against all tungsten lamps by the European department of IDIOTS (International Department of Incompetence Over Technical Subjects) has been causing us concern. We could buy stock of lamps, but I've a feeling traditional dimmer racks may start to become harder to source as they gradually get retired.

 

The futures bright. But it ain't all LED yet.

Anyone involved in the (TV) lighting for this? Looked to be an all-LED rig this year. Maybe not as bright as in previous years, but much more even coverage, & obviously much more colour. The projection looked brighter as well - maybe cos the "floor" was a bit dimmer?

 

Main lighting. Layer of traditional PAR cans and lots of PRG Best Boys.

 

Strong move towards LED units this year, but the technology isn't quite there yet. Particularly in the area of water resilience.

 

Filming was different. Normally a lighter/brighter bias is applied for the cameras, but this year was using the normal show lighting with minor adjustments.

 

There was projection onto the arena itself this year, but it was a juggle between projection intensity and the show lighting. (And space on the lighting gantries!)

That's always been the case with the entertainment industry. A job perceived as glamorous and therefore a plentiful supply of enthusiastic young people willing to work for low or no wages, and sometimes so up the their neck in drama-college debt that they will undercut and back-stab out of financial desperation.

 

What's more disturbing is the increasing expectation of young exploited people to do installation or repairs on electrical equipment in an industry that is notorious for word of mouth training that is often very wrong. (There are STILL people disconnecting earth wires.)

 

The bottom line is that if you want a well paid job choose something unglamorous (but usually with REAL training) and keep theatre tech as a sideline.

I'd suggest proceeding with caution. Many of the cheap DMX lights have appallingly poor isolation on the power supplies and there's a slight possibility that there may be mains referenced voltage on the DMX connector of your light.

 

Where did you get the light from?

 

(I kinda want to buy it off you to do some electrical tests.)

I think the biggest use will be setting addresses and modes on RDM compatible fixtures. For that the bluetooth one looks the most appealing.

Rather predictably, the answers have filled me with indecision. I do like the idea of addressing fixtures remotely from my phone though.

The DMX cat definitely looks quite versatile compared to the small user interface of traditional testers.