gyro_gearloose

Pretty sure that shoving an LED into a moving mirror was my idea from just over a decade ago. Wonder if I can get any royalties? 😁

I should have been a bit clearer. One of the sound ops is mixing for broadcast, so would rather not hear the room at all! The shows run off timecode, so no traditional cues are given by the SM.

At work we've got Beyer DT109 headsets for our sound ops. At the moment they have two headsets, one for comms and one for the desk. What I'd like to do is combine the output from the sound desk with the output from the comms beltpack, to get away from needing to swap headsets. Ideally I'd like a simple box that the comms, sound desk headphone output, and headset wired for stereo all connect to. The headsets mic would simply connect to the XLR4 plug into the belt pack. I don't want to mess about connecting comms to a desk channel, and I want only the sound op to hear the output from the desk. I'm aware that some comms base stations have an aux input, but that's no use for this situation. An off the shelf solution would be great, as long as it's not too expensive or clunky. However I'm not above building one from scratch, if someone could suggest a suitable circuit or two. Thanks in advance.

I don’t work there anymore, but when I was last at the Marina Theatre in Lowestoft there was the old Vision 10 and the backup crate sitting unused in storage. I don’t think we ever had the software on disc, but you could always clone the hard drive. Drop them a message and I’m sure they’ll be glad to be rid of the thing 🙂

We had this exact same problem a few years ago. The projector was powered from the shows distro on stage, while the sound desk and QLab Mac were powered from a different supply at front of house. This is usually fine, especially with the use of Cat5/6 in place of traditional analogue multicores. However as soon as the HDMI lead from the projector was plugged in to the laptop there was buzz from the sound system. In the end we solved the problem by running an extra power cable from their distro to the front of house mix position, thus eliminating the ground loop, and the buzz.

Scroller cable seems to still be available. These guys appear to sell it by the metre.

Acetate gobos in a Selecon Pacific might be more reliable if you need detailed/coloured gobos.

Source four glass gobo holders go in the iris slot, not the metal gobo holder slot don’t they? Maybe the lamp peak needed adjusting because the glass gobo was in a different focal plane to metal gobos?

If the lamps won't be visible, how about making up a flat plate covered in LED tape? You could use RGB or white tape, and there are plenty of low voltage LED DMX-able drivers out there.

Stage Depot have some here. Not cheap though.

If you are 30-40 volts continuously to the fluid pump, then you may have a dead Triac. Have a look at this thread from a few years ago when I was having some similar issues with our Unique.

The CPU, stepper motor drivers, and logic and motor power supplies are all on the same circuit board so the fault won't be with the wiring. The drive current is controlled by four sets of three resistors in parallel for both pan and tilt. If there is a fault with any of these resistors then the driver chip will supply less current to the motor resulting in a loss of torque. To test your resistors you'll need to take the driver chip out of its socket and measure the resistance between ground and four other pins. There are four ground pins you can use (pins 5, 6, 17, and 18), and you'll need to measure the resistance from any one of these to pins 9, 10, 13, and 14. You should get about 0.5 Ohms. Anything higher than that means you have a problem. This method only works for the pan and tilt circuits as they use the PBL3772N driver chip. All other stepper motors use the PBL3775 chip which has the same ground pins, but you only need to check the resistance to pins 2 and 21, which should be 2.2 Ohms. Its well worth signing up to lightspares.com as they have part and circuit diagrams for all sorts of fixtures. They have the circuit diagram for both versions of Mac600s, for example, which will help you with troubleshooting your lights.

Don’t bother getting your belts from Martin. They are a standard size/tooth profile, so you will be able to get them cheaper from engineering supply companies. These guys have probably got what you need. Are you sure it’s a mechanical problem? If the motor drive circuit develops faults, the motor will still turn but it will have less torque. This will make the motor lose steps if it’s trying to move the head too quickly, and will sound like the belt is slipping.

If an otherwise perfectly working older Mac started having pan/tilt issues, I’d suspect the electronics if the mechanics all seem fine. I know from experience that the pan/tilt stepper motor driver circuit can develop faults with the current sensing resistors. Fixing those kinds of faults requires you to replace surface mount components, so I hope you’ve got a good soldering iron and a steady hand! @knightdan - what problems are you having with your Macs? Do pan and tilt work at all, or only at slow speed? Given the age of your Macs problems can arise for any number of reasons, such as motors being worn out, wiring looms breaking, faulty motor drivers, or the optical sensors failing.

As and when travel is allowed again you should head over to Southwold pier near my home town of Lowestoft. They've got a mechanical clock that Tim made as well as the 'Under the pier show'. The chips are rather nice too.

Have you tried contacting Prolights directly? There’s a contact form on their website.

Aside from the blue pinch and the frankly god-awful GKV lamps, Pacific’s could also be fitted with T/25, T/26, and M40 lamps. Having only used T/26s in Strand Preludes, I’d be interested to see how much brighter they would be when used in the ellipsoidal reflector of a Pacific.

Are you converting spots or washes to LED? I have used small diameter 40W LEDEngin LEDs in place of discharge sources while retaining the condensing optics. The current crop of high current/brightness COB LEDs look like they are too big to simply be a drop in replacement in a spot, but I’m not sure that wouldn’t be a problem for a softer edge wash fixture. I did exchange a few emails with a UK lens company trying to find a solution for using comparatively large diameter light sources in condensing optic systems. Nothing came of it in the end as they kept trying to push me toward using a skilled optic designer for what I thought would be a simple system to design. I think they thought I wanted the last word in optic precision, and not the fairly crude lenses usually found in theatrical fixtures.

You'll have to stick with mechanical dimming if you want smooth dimming at lower percentages. According to the datasheet, and in line with most other Meanwell drivers I've looked at, the driver linked to earlier doesn't dim smoothly below 8%.

Just wanted to add what little experience I've had with Powersoft amps. A few years ago I was helping a friend service a local clubs sound system. They had a 1U/4 channel Powersoft amp (can't remember the model) that wasn't working, so we took it to a local electronics engineer who we've used for years to repair other amps. It turned out that the capacitors Powersoft used were custom items which our engineer couldn't find suitable replacements for. I don't know if that issue still persists with newer Powersoft amps, or if its just limited to their 1U amps.

Do you really need to weld your batteries? Would a battery box like one of these work for you? If you need to use more cells, how about a solderless modular battery holder system? I haven’t used one myself, and only found it when looking for 18650 cells with screw terminals. Turns out such a battery doesn’t exist, but they do make 10AH 38120 cells with screw terminals.

If they only want to pay a few hundred pounds then you really need to look at a PC based system, based around a secondhand computer. I’ve done something similar for a small local nightclub. I used MagicQ running on a computer with a touchscreen monitor. It was set up to run MagicQ on boot up, and MagicQ was set up to only show a grid of buttons corresponding to different lighting states for some movers and some LED wall panels. I was going to suggest a secondhand Showcad Artist system, but the one on eBay right now is priced at £400!

That’s good to know. Good luck with the conversion.

Try removing the tilt drive belt so there is no load on the motor. Power the unit up and see if the motor tries to move. It might judder without turning, or it might not turn but be really hard to turn by hand. If this is the case then the motor driver chip is dead. However, if you can freely spin the motor by hand while the fixture is powered then you either have a broken loom or a faulty power supply. IIRC, pan and tilt use a different power supply to the other motors. There should be three LEDs on the motherboard to indicate wether the supplies are working. There might even be fuses for the motor supplies. You should have a 5 volt supply for the electronics, 12 volts for the smaller motors (colour, gobo, etc), and 24 volts for pan and tilt. If the fault is with the driver chips, don’t just replace them without first trying to find the cause of the failure. Check the looms for breakage, especially where the loom passes through the pan bearing. Also check the resistors around each driver chip. The original Mac 250/300s had a failure mode where the resistors used to determine the pan/tilt motor drive current would fail, and thereby drastically reduce the current and therefore torque that the motors could use. This would then lead to juddery/no movement, and many errors on startup. Mac 500s and 600s, while using a different motherboard, can suffer the same problem.

I replaced the lamps in some Clay Paky Miniscans with LEDs a few years ago. I first wrote about it here 8 years ago! Things have moved on with LEDs since then, and I’ve been keeping an eye on LED development with a view to converting some moving heads at some point. Last year I put up a list of parts I was looking at to use in any potential conversion. I haven’t managed to find any fixtures to convert, and with the current situation I’ve put any such project on the back burner for now. As for converting your Mac 600, there are a few issues with them that would put me off converting that particular fixture. You say you would be using the fixture in a small space, so you might need a wide beam angle depending on how much of the space you want to light. Unfortunately the standard Mac 600 lens is 25 degrees, but the frost wheels might help with that. The other problem with Mac 600s is that the original discharge lamp uses a huge heatsink that gets in the way of fitting the LED and it’s own heatsink. I’m not sure how you could use the existing heatsink to cool the LED as you would need to mount the LED somewhere near to the focal point of the reflector otherwise you risk losing a lot of light output. You could remove the existing reflector and use the LED/holder/reflector optics that I mentioned in my post from last year, but fitting them in the Martin heatsink might be tricky. Hope this helps.