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Do faulty inline filters blow fuses?


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Hi,

 

I have a TZ working until one day it blow the fuse inside the inline filter assembly.

 

What I have done

I have disconnected the Inline filter assembly from the transformer.

Replace the fuse (the other one was blown - black as)

Check inside the assy to see any loose wires.

Checked where the power cable connects into the machine for loose wires or shorts.

Tried again with no luck.

 

Other factors

The power cable is 6 months old and has never had a problem.

The fuse is an SB 5 amp as to the manual.

Everything looks fine.

 

In the assy, I can see the fuse holder, the power switch and the inline filter.

 

My guess is the filter is bad, sound correct?

 

Filter.thumb.jpg.d2ce11457d5e67601ff66a1b77f13f25.jpg

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I'd expect to see something like this:

http://www.pinwiki.com/wiki/images/a/a5/WPCPowerBoxInside.jpg

 

Any markings on the pink disk? It looks like a varistor has popped previously judging from the scorch and the small piece of leg on the white terminal.

Edited by ajfclark
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Usually first just cut the varistor out as it’s power spike protection and would most likely be bad causing the fuses to blow.

 

If the fuse still blows then look at the line filter and wiring.

 

Don’t forget to install a new varistor.

 

 

Sent from my iPhone using Tapatalk

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Granted the EMI Filter is probably shot, Couldn't the problem still be further up the line past the filter.

 

Apparently what is supposed to happen is

If voltage rises above 275 (varistor) volts, It shorts all/excess power.

 

The Thermistor is a Negative type meaning it's high resistance cold and low resistance warm.

This limits inrush current (From charging large caps etc) so as to not stress the power supply.

 

As Dedrok says, Snip the varistor (Incase it's failed and shorting).

But be sure to replace it with a new one.

Edited by ozfalcon
Corrections
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As Dedrok says, Snip the varistor (Incase it's failed and shorting).

 

The varistor already looks to have been cut out in his pictures. That's what I thought didn't look right in the original picture. You can see the little bit of the leg on the right terminal of the filter and the scorch mark from it blowing on the card.

 

That makes me think everything there has possibly already seen surge conditions. I'd replace the filter, varistor and thermistor.

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The varistor already looks to have been cut out in his pictures. That's what I thought didn't look right in the original picture. You can see the little bit of the leg on the right terminal of the filter and the scorch mark from it blowing on the card.

 

That makes me think everything there has possibly already seen surge conditions. I'd replace the filter, varistor and thermistor.

 

Yeah , later I had a good look (on the phone) and yes I did notice that the varistor was already gone.

 

 

Sent from my iPhone using Tapatalk

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The varistor already looks to have been cut out in his pictures. That's what I thought didn't look right in the original picture. You can see the little bit of the leg on the right terminal of the filter and the scorch mark from it blowing on the card.

 

That makes me think everything there has possibly already seen surge conditions. I'd replace the filter, varistor and thermistor.

 

Agreed.

@koolego that looks like a switch after the filter, So if the switch is OFF (No load after the filter) and it still blows a fuse then it has to be the filter.

Either way, I'd be replacing everything. Thermister, Varister & Filter.

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it is all good and well to ask for advice for repairs like this, but please remember that 240V will kill.

I don't recommend working on this unless you understand what you are doing, but if you do at the very least make sure :-

 

Your machines are tagged and tested... this should indicate if there are issues with insulation or earthing to the external metal parts of the cabinet.

earth leakage or better still, an RCD on the circuits ( all outlets preferably ) powering your machines.

an RCD will almost instantly turn off if it detects current differences between active and neutral of any device on the circuit.

 

Nothing can really protect you if you touch active and neutral as you become just another load on the circuit.

 

It is important not only for you, just remember you probably aren't the only one playing the games, so if in doubt leave it for a professional.

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...Either way, I'd be replacing everything. Thermister, Varister & Filter.

 

Well, I guess if I have the solder iron out I can just replace the everything.

Does anyone know the specs for the Thermister and Varister?

 

I am guessing its an order into Marcospecialties unless anyone can recommend local supply's

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it is all good and well to ask for advice for repairs like this, but please remember that 240V will kill.

I don't recommend working on this unless you understand what you are doing, but if you do at the very least make sure :-

 

Your machines are tagged and tested... this should indicate if there are issues with insulation or earthing to the external metal parts of the cabinet.

earth leakage or better still, an RCD on the circuits ( all outlets preferably ) powering your machines.

an RCD will almost instantly turn off if it detects current differences between active and neutral of any device on the circuit.

 

Nothing can really protect you if you touch active and neutral as you become just another load on the circuit.

 

It is important not only for you, just remember you probably aren't the only one playing the games, so if in doubt leave it for a professional.

 

Great advice you know of such a professional to recommend?

 

 

Sent from my iPad using Aussie Arcade

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Great advice you know of such a professional to recommend?

 

 

Sent from my iPad using Aussie Arcade

 

Testing and tagging is only for commercial premises, and even on new goods is required, i have never seen test tags on anything sold at harvey norman.

 

We are test and tag certified but rarely required.

 

https://www.appliancetaggingservices.com.au/blogs/vic-test-tag-requirements

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Anyone can test and tag if you have the equipment to do it. Years ago only a licensed electrician was allowed to do this work and that is now no longer. If an appliance is found to be faulty most of these guy's wouldn't know where to look for a repair. Also under AS3000 it is for portable appliances, generally pinballs are not considered portable because of the weight and size they come under so don't be fooled into thinking everything with a plugtop needs to be tested and tagged.
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Just a quick thanks for everyone for the support, one small note, the replacement filter is just a little smaller so you will also need a little extra wire from the thermistor to the fuse and heat shrink to cover the joint.

 

tzWorking.thumb.jpg.f81afca59026a64c3b7f0112b8b333f5.jpg

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I wouldn't bother with the thermistor but the varistor is there to protect your machine from lightning strikes entering in the mains cable. Rated at 275volts, it is designed to dead short the mains active to the mains neutral at any voltage above 275volts momentarily till the inline fuse blows and opens the circuit.

 

It is a sacrificial part that only works and protects once. Sometimes when it blows it DOES take out the noise filter as well as the line fuse but better that than allow the high line voltage to enter into the transformer and raise all the output voltages including the 5vDC even though it is regulated. (It simply isn't designed to regulate quick enough and even a pulse of 7-10 volts on the 5volt line will blow just about every chip on every board).

 

I write this as a warning and ask all owners to take the time and check the varistor is in place and NOT bypassed on your beloved machines.

 

A bypassed noise filter will allow noise into the machine and is usually the cause of unwanted noise in your sound but a bypassed varistor shows no warning signs, it simply won't protect your machine when you need it.

 

Take the time to check as I have found many machines with bypassed varistors especially imported machines.

 

They are one of those parts that when blown can be bypassed to "keep the machine going" but rarely are replaced as "the machine is now working fine".

 

The varistor is pretty easy to check. They usually blow the side clean out of them and burn the inside of the containing box.

 

As for the wiring, they are not a fuse and wired in series, they are wired across the power lines active to neutral meaning they are open circuit UNTIL THE VOLTAGE GOES OVER 275volts then they conduct causing a short circuit that WILL blow the inline fuse killing the mains power.

 

Without one working, the fuse will NOT blow as fuses are not voltage dependent allowing the high mains voltage to go straight into your machine costing you a lot of money to rectify.

 

Please take the time to check your one is in place and not bypassed or taken out.

 

Just as a side note, 110 volt imported machines use a varistor rated at only 175volts so it must be changed but most are simply bypassed and sold on.

 

The thermistor, is simply there to blow on overheat conditions but your fuse will blow anyway.

 

As they offer no real protection, most that blow are never replaced.

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Anyone can test and tag if you have the equipment to do it. Years ago only a licensed electrician was allowed to do this work and that is now no longer. If an appliance is found to be faulty most of these guy's wouldn't know where to look for a repair. Also under AS3000 it is for portable appliances, generally pinballs are not considered portable because of the weight and size they come under so don't be fooled into thinking everything with a plugtop needs to be tested and tagged.

 

I agree but it's not so much for compliance I was referring to, imported machines as you may have seen come with all manor of wiring hacks. How many people have tested the integrity of the earth on their 20 something year old pin... it could save your life. Albeit you can test it yourself with the right equipment or at a minimum do a continuity check from exposed metal (coin door, side rails legs etc.) to the earth pin but also checking insulation breakdown isn't a silly idea either.

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AS3000 is for fixed wiring like the power points, light switches, etc in your home or office. AS3100 covers the electrical construction of portable appliances. Portable in that context means it has a user disconnectable plug. The size and weight of the appliance is not relevant for the most part. AS3760 covers portable appliance testing.

 

Everyone with a pinball or arcade machine should check for continuity (low resistance; 1 Ohm max) between the earth pin of the mains plug and the exposed metal of the machine. This is the most important test, as a good earth connection will protect you against electrocution in the event of an internal fault. Leakage faults will be caught by the RCD in your switchboard.

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