IMPORTANT : Prevent your EQ6 board from frying

[Catanonia]

As you may have known, my NEQ6 Pro board got fried last month and I have now recieved a new working board for £100 direct from OVL via Bern @ Modern.

I must have had a power surge and hence the problem.

Looking closely, I believe (and others) that there is a fundamental problem with the design of the EQ6 power protection.

They supply you with a Cigar Lighter method of powering the mount from 12 volts. This has a 5amp fuse in it for protection if you unscrew the end and have a peek.

Those that power from a 12volt power adapter from the mains have no such protection fuse and are at the mercy of the boards components. In particular there are a few VERY small components that blow and save the motors and the rest of the mount. The problem is that if they blow, they basically make the board useless unless you are very skilled at repairs of small components. That is if you can find which ones are at fault. (usually L1 and L2)

So after recieving my new £100 board, I decided to make my own protection fuse mechanism for 12v from the mains to protect the new board from power surges.

For a few £'s from Maplins I bought an inline fuse holder andf butchered the extension cable from the 12volt supply with a 5amp fuse inline.

A few pictures of the quick and simple mod that hopefully will save me a few £'s in the future.

I would suggest that all people running EQ6 mounts from the mains via a 12v adapter think about how they protect their boards too.

I think this is a bad design flaw, the EQ6 board should have a build in fuse that protects the unit on the actual board.

A few piccies for you.

Cat

[steelfixer]

That is strange, you would have thought they would have put one of those 'quick blow' type fuses in to protect it.

[Gina]

Good point. I think I'll put a fuse in the mount and at the same time fit it with a new power connector of a much higher quality. I'm running my mount off a high quality analogue PSU but some added protection is a good idea.

[Carbon Brush]

A bad experience.

I don't know the details of the EQ6 innards, or your mains supply arrangements. But probably general electronics advice applies here.

First of all, for a fuse to blow, one of two conditions has to be met.

1/ There has to be a fault already in the equipment. In which case you can only expect that the fuse blows before wiring melts, tracks burn off the PCB, etc. But you still need a board repair or replacement.

2/ Alternatively, there is a problem with the incoming power. This causes the equipment to take excessive current and then the fuse blows. The most likely problems are excessive input voltage, or reversed supply. It is possible to design in protection to blow the fuse before other damage is done. You then sort out the supply, change the fuse and all is well. But this approach costs money and every mount/goto kit maker is under pressure to sell for ££ less than the competition. So this protection is oten omitted.

I have seen many 'off the shelf' mains power supplies that give unregulated output, up to around 19v on low/no load for a supposed 12V supply. A recipe for drive or handset destruction. Always check the supply with a voltmeter before first use. Never believe the label until you have seen the result on a voltmeter.

A few pounds on a multimeter is astro money very well spent now that kit contains increasing amounts of electrical and electronic components.

There is a long standing joke amongst electronics engineers regarding fuses.

The semiconductors (transistors, chips, etc) are there to protect the fuse.

Quick blow and anti time delay fuses are very little help in protecting electronics. Unless you buy the really high speed semiconductor fuses intended for specialist applications. But, do you fancy paying £5-£10 for a high speed fuse?

Hope this is useful.

[Catanonia]

I asked for quick blow 5amp fuses for my modification.

I have no idea if this mod will help protect the mounts PCB, but worth a few £'s to impliment it.

[Catanonia]

That is strange, you would have thought they would have put one of those 'quick blow' type fuses in to protect it.

You would, but they haven't. They rely on the fuse external which they supply within the cigar lighter that comes with the mount.

No mention anywhere about being careful if you don't use this method of powering the unit. You only find out when the problem happens.

[Macavity]

TBH, I'm not overly fond of cigar connectors (Changed to XLRs) or the supplied "power" plug-socket on t'other [mount] end. Even at a mere 12V, I've blown fuses, while casually plugging-unplugging stuff. I use "external" switches too...

[RikM]

I use an external 12V PSU but plug the mount into it using the cigar lighter cable that came with the NEQ6. I have a 30mA RCD socket on the wall end of the extension as well. Is that enough protection or do I need to do more?

[barkis]

Are the boards Reverse polarity protected? In which case, wrong connection wouldn't be a disaster. A semi conductor in the DC in line would suffice. Perhaps there is one already in there.

[Gina]

The way to protect electronic equipment from power supply failure is a fuse and what is called an "over-voltage crowbar" this may consist in the simplest form of a zener diode feeding the gate of a thyristor and a fuse in the supply line. When the supply voltage exceeds the zener voltage (plus thyristor gate conducting voltage) the thyristor fires, short circuiting the supply and blowing the fuse. Supply voltage spikes can be removed with special semiconductor devices designed for this purpose. Mains equipment is best protected by spike suppressors in the mains supply line - these are very readily available from most electrical shops etc.

[malc-c]

I always thought that it was excessive current draw that causes a fuse to blow, not voltage. Fuses should be rated at X amps at a given voltage to work efficiently, so using a 5a household fuse would be no use on a 12v supply.

My guess is that the original supply was running at over-voltage. As one of the other posters has stated, often these 12v rated switch mode PSU's output as much as 19volts until load is applied. I use a 5amp 13.8v regulated PSU that has a built in output fuse for over current draw, and haven't had any electrical issues with my HEQ5

[Catanonia]

I will add everything was fine for 2 years in an obs and mid session the eq6 fried. Could have been board failure.

[pete_l]

Those that power from a 12volt power adapter from the mains have no such protection fuse and are at the mercy of the boards components. In particular there are a few VERY small components that blow and save the motors and the rest of the mount. The problem is that if they blow, they basically make the board useless unless you are very skilled at repairs of small components. That is if you can find which ones are at fault. (usually L1 and L2)

I must admit that I'm not familiar with the internals of an EQ6's circuit board, bit one thing comes to mind.

Boards often have fuses included, but with miniaturisation it's sometimes hard or impossible to tell which surface mount component is a fuse. However, if there are some marked L1, etc. then I'd assume the "L" stands for Link and that they may be the protective fuses. If they've blown that would make it more likely.

[Catanonia]

I must admit that I'm not familiar with the internals of an EQ6's circuit board, bit one thing comes to mind.

Boards often have fuses included, but with miniaturisation it's sometimes hard or impossible to tell which surface mount component is a fuse. However, if there are some marked L1, etc. then I'd assume the "L" stands for Link and that they may be the protective fuses. If they've blown that would make it more likely.

And they are about 2 mm in size on the board.

Hopefully my simple fix will stop it happening again.

Well worth a few quid

[Carbon Brush]

Excellent description of one supply line protection method from Gina.

The 'fast' fuses I mentioned are not standard 'shop' quick blow fuses. They are specialist semiconductor protection fuses available from only a few suppliers. Though spending on a good circuit protection, like that described by Gina, avoids the need for expensive fuses.

There seems though to be little interest in actually measuring supply voltage though.

Multimeters cost a lot less than the damage.

L, on a PCB usually denotes an inductor. In this case probably for intereference suppression.

[Islander]

I always thought that it was excessive current draw that causes a fuse to blow, not voltage. Fuses should be rated at X amps at a given voltage to work efficiently, so using a 5a household fuse would be no use on a 12v supply.

My guess is that the original supply was running at over-voltage. As one of the other posters has stated, often these 12v rated switch mode PSU's output as much as 19volts until load is applied. I use a 5amp 13.8v regulated PSU that has a built in output fuse for over current draw, and haven't had any electrical issues with my HEQ5

For a given load impedance/resistance, an increase in voltage will lead to an increase in current. Fuses don't blow that quickly - even the quick blow types don't - they'll tolerate a current overload for a surprisingly long time before the wire fatigues and melts.

If you want a quick disconnection provided by a fuse on overvoltage then the crowbar circuit Gina described is the easiest method. A suitably rated diode (say, 5A or so) across the supply rail with anode to negative and cathode to positive in conjunction with the crowbar will provide the same fast protection for accidental reversed supply connection.

[beamish]

Owners of HEQ5's take note !!!! this applies to you too since this how my main board blew out a few good yrs ago

[Stephen]

Is this only required if you are running from the mains, or could battery users encounter the same thing?

Given I have a centralised power distribution box (Mount Hub Pro) that only has (I think) a single 15A fuse inside the box, should I be fusing each of the power out cables to the specific devices they are running to?

I run from a single 65Ah lead acid battery.

[dmahon]

They rely on the fuse external which they supply within the cigar lighter that comes with the mount.

Does it?

I'm sure I got a cheap one with my Maplins power tank and bought a good one from Bern. I don't remember getting one with the mount at all.

[Digz]

Interesting read and discussion. Im hoping my regulated power supply with short circuit protection and current limiting will protect the board etc.

[Islander]

Is this only required if you are running from the mains, or could battery users encounter the same thing?

Given I have a centralised power distribution box (Mount Hub Pro) that only has (I think) a single 15A fuse inside the box, should I be fusing each of the power out cables to the specific devices they are running to?

I run from a single 65Ah lead acid battery.

Batteries don't vary in output other than their voltage decreasing as they discharge. However, if a battery connected device develops a fault that presents a low resistance, then it may be damaged by excessive current flow - batteries can dump a lot of energy very quickly. Individually fusing connections is a good idea

[Stephen]

Batteries don't vary in output other than their voltage decreasing as they discharge. However, if a battery connected device develops a fault that presents a low resistance, then it may be damaged by excessive current flow - batteries can dump a lot of energy very quickly. Individually fusing connections is a good idea

Looks like Maplins is getting some more of my money then Thanks.

[Catanonia]

Does it?

I'm sure I got a cheap one with my Maplins power tank and bought a good one from Bern. I don't remember getting one with the mount at all.

All,

It depends on how you power your mount and what protection it gives you.

In my case I bought a standard 12v supply unit for the mount (looks like a laptop power pack) and plugs directly into the mains. Because I did this, I soley relied on the fuse inside the plug of this adapter. It didn't protect against the output of the unit though and hence the problem.

So check your 12v supply, and good points about multi meters.

But personally for a few £'s, if you don't have protection for more than 5amps into the mount directly, I would invest in the quick fix.

[Rob]

Interesting read. I've just bought an original EQ6 (black non guide port model). It will of course come with a battery pack. I'm looking to make a 12v cigar lighter cable.

Firstly I'll make sure it has an inline 5amp fuse. Also can someone please confirm what size the tip is?.. and I ssume its tip positive?.

Thanks

Rob

[Gina]

Yes.