DrV

There's an eeprom.

I think it might well be a 24lc16. I would check that pin 4 goes to 0v, pins 5 & 6 go to pins on the microcontroller chip and pin 8 goes to +5. The other pins might have connections but where they go is less predictable. The chips are only £2.43 for 5 from RS so I'd say it's worth a punt. As for what's stored on there, 16k bits (2k bytes) is a lot for just 2 bytes of DMX address but the dimmer has other stored parameters eg, standalone levels or sequences, switch pack mode. It may also be the same chip used on more complicated models. And the price difference between a 2kbit part and a 16kbit part is only pence. I would be surprised if there's anything in there which you have to pre-load for it to work. One thing that occurs to me - are you exiting out of setting the DMX address (by selecting another menu option) before powering off? It might not save the address immediately as there is no Enter button to confirm.

What's that 8pin chip in the top right of your board? The max485 is the DMX transceiver but the other might be an eeprom. Can you see the part number?

Have done that with a HackRF although not in any scientific way - just out of curiosity.

PSU faults due to worn out caps tend to be less subtle than just reducing output voltage or current. I just mentioned them because you were talking about second hand fixtures.

I'd add that the LEDs themselves are not the only components which wear out. Almost all LED fixtures will use a switch mode power supply. This uses electrolytic capacitors and these have a specified life. This life depends on factors such as how close to their rated voltage they are run and their operating temperature. In a cheap fixture the design may be such that they are running nearer to these limits than in an expensive one so the life of the caps may be the limiting factor.

Yes they do, using the Pathscape configuration manager (software).

Another vote for a variable current limited supply. I've got a pair of 0-60V 1A supplies which I can connect as a tracking +/- pair (for audio stuff) or use individually and they rank in importance with the 'scope as essential items of test kit. Keep the supplies you already have for second stage testing (once you think you've sorted the initial problems) and invest in a proper bench unit with current limiting for initial powering up of a faulty item. They're not that expensive and are an incredibly useful diagnostic tool.

That's what Pathway Connectivity is all about. You can have nodes which connect DMX or ethernet onto the backbone then you can connect nodes to tap off DMX from that. You can also do stuff like having a DMX node which picks up one range of addresses from one universe and another range from a different universe and so on. As ever I must declare a connection, although not an interest in that I do a bit of work for CTI.

On reflection it is probably a resistor across each of the Y caps so you don't get a shock if you pull the mains out at the to of a mains cycle and touch the pins. We used to have a Kenwood 'scope that didn't have the resistors. Ask me how I know!

Some Strand Act6s have this.

IIRC mine had all the filters at mains potential and an isolating transformer on the audio input. I expect it had plastic shafts on the pots but I bet the bushes for said pots were metal. The front panel was hardboard so that was all perfectly safe!!!

You shouldn't have been sitting on the bench in the first place...

Does it? Looks like they are the same way round to me, both the symbol and the polarity marking. Not the only weird thing either - [quote] The first capacitor may have a capacitance that is larger than the capacitance of the capacitor of one channel of the power supply of the amplifier. [/quote] and [quote] Without wishing to be bound to a particular theory, the applicant assumes that the first capacitor acts as a powers storage that ensures that all parallel connected loudspeakers are supplied with power. [/quote] I have opinions on both of these but decided to delete them as I don't know enough about the law to risk expressing them! Read, digest and form your own opinions.

Indeed, but the usual arrangement is to put two in series with opposing polarities (obviously twice the required value).

Without doing the maths (cos I've forgotten most of the a.c. theory I ever knew, which wasn't much to start with) I suppose the principle is that having a fat capacitor in there limits the current at low frequencies, where the speakers are nearly short circuits, and the speakers themselves limit the current at higher frequencies because they are mainly inductive. (Ignoring all the weird stuff that happens around resonance!). What I would question though, is the assertion that you can comfortably use polarised electrolytics in such a circuit. When they were used as the output caps of transistor amps that was because the output was sitting at half the supply rail so one end was (usually) +ve w.r.t. the speaker terminal, the other side of the speaker being connected to the -ve rail.

Brings back memories - in the 70s one of my first 'big' projects was a three channel bass, mid, treble sound to light controller for my yoof club! Later adapted to 3 channel sequential when I learned how to divide by 3 with j-k flipflops. From little acorns... Of course from a safety point of view it was horrendously dangerous, but I never killed anyone, well, no-one ever complained that I had killed them!

From the Vietnamese Sailing Club case study: [QUOTE]Standard laws of physics would dictate that the ability to connect speakers in this fashion is not feasible.[/QUOTE] So which particular non-standard laws of physics do they follow instead..? I'd really like it not to be snake oil as it would be very interesting, but when someone claims to be able to break the laws of physics you have to wonder. Shall we all contribute so that Big Clive can buy one and explain it to us?!

Is anyone here familiar with this kit? I've been asked to look at one but I'm beyond learning about new audio kit now, especially when it looks a bit complicated. I'd like to pass it on to someone who can take it on. Dave

If anyone is interested in my setup, it was a 7Ah 12v battery with a wireless dimmer attached, set in non-dim mode. This was supplying 600mm of 12V pixel tape and an Arduino Nano which was pre-programmed with the light sequence so all I had to do was turn it on and off. One of the other channels on the dimmer was supplying a length of ordinary white tape inside a light fitting made to look like a fluorescent. The lift was simply painted on the back of a box on wheels, with the indicator at the top and the front was a toilet cubicle with full size porcelain! The battery and the dimmer were stuffed down the loo, out of sight but easily accessible (with the wires coming out via the soil pipe). I hasten to add it was a brand new unused article😁 Whole thing worked a treat. Battery life was not an issue as the total watt-hours used was negligible.

An advantage of addressable tape is that the dimming is built in. However, as you already have dimmers available that's negated. Also the quiescent current drain of a length of addressable tape is likely to be higher than that of a dimmer, and of course it goes up with the length of tape, whereas with standard tape it is constant regardless of how long the tape is. It is fun to work with though so when you get a chance, buy a bit and have a play. We've just done a show with a lift in it and I made a very effective floor indicator! Easy 😁

Next caps to check are the output caps which are the four similar ones inside the left heatsink. It could be loose windings in the transformer but you can't just swap that out so try the caps. Also check that the choke in the middle of them is ok (no loose wires or cracked varnish). Other than that I'm out of ideas without a waveform to look at. I don't know but it might be possible for a faulty/worn out snubber circuit on the primary side to upset things (look for at least 2 of a resistor, cap and diode across the primary winding). Not very easy to diagnose remotely and you might be better off getting it to Jamie Sherlock if he's got experience of these particular units

Difficult to determine without a 'scope. Does it squeal all the time or only when you bring the lamps up? I still think it might be the decoupling cap for the chip in the PSU. This is probably the one above the transformer and next to the small vertical PCB in the top centre of your picture in this post. I've certainly seen this create the same effect on other SMPSs. The switching frequency becomes unstable so instead of having a single frequency that only bats and teenagers can hear you get artefacts in the pensioner's audio band.

That sounds as though the control board has a short Check its 12v input with an ohmmeter. Favourite faults there would be a decoupling cap (if there's a dead short across either the 12v input or the regulated 5 or 3v3 supply rail) or the DMX transceiver chip. The reason to suspect the chip is that it's exposed to the outside world. I don't have any experience of the Kam bar but just as generic fault finding these would be my go-tos. Alternative methodology would be to try powering the control board from an external, current limited bench supply.

As a general rule you can replace NiCd with NiMh in low power situations like this.