I burnt out a component on the PCB of my 1980's Japanese pinball machine (known as a pachinko machine) and was wondering if anyone can give me some info on it ... (see pic)

its a 24 volt AC system and the component markings are:

470K 411(?) where (?) is either a 9 or a symbol

a). Tell me what it is and what its ratings specs etc. are?
(I think it's a Zener Diode as the PCB has ZD3 marked below it)

b). Where can I get a replacement

c). can I substitue another component for it.

thanks folks

Craig

 

Considering the legend on the pcb, I would guess it's a zener diode, however the 470k marking is puzzling. It's also an odd shape for a zener or a resistor.

 

Show us the rest of the circuit board.

 

I agree with tracecom it doesn't look like a zener, it looks more like a capacitor.
So could you need a new one simply because the wrong component has been inserted at some time past?

Some detective work may be needed to find a circuit.

Make and model numbers etc of board, machine and so forth please.

 

Looks more like a 47VDC (30 ish VAC) MOV?

 

The markings on the device suggest MOV while the markings on the board suggest TVS (back to back zeners). Either is possible in the same location so the board may have been designed for a TVS then populated with an MOV.

 

varistor
at least the symbol is consistent with such.

 

The symbol is not the customary one for a VDR or MOV, Teccor use this symbol for their Sidactor SCR type suppresion devices.
Max.

 

Here it is fellas, thanks for the great response

Its from a 1980's pachinko (japanese pinball)

By the way I know nothing about electronics, but I'm willing to learn (I'm a computer programmer for the last 30 odd years so please don't hold it against me)

Specs : 24 volts AC 3 amp 100VA

The black connector right of the 13 pin connector is where the 24 volts AC goes in the other 4 colored ones go to the machine


cheers and thanks again for the help

Craig
vandekamp.com.au - my profie here if you're interested[/QUOTE]

 

Thanks. So it is a 47V MOV.

This is used for protection against voltage surges. If you remove this component it will not affect the operation of the circuit. It is faulty if it registers with low resistance when removed from the circuit board.

 

Here it is fellas, thanks for the great response

Its from a 1980's pachinko (japanese pinball)

By the way I know nothing about electronics, but I'm willing to learn (I'm a computer programmer for the last 30 odd years so please don't hold it against me)

Specs : 24 volts AC 3 amp 100VA

The black connector right of the 13 pin connector is where the 24 volts AC goes in.

[CLICK IMAGE FOR FULL SIZE]

cheers and thanks again for the help

Craig
vandekamp.com.au - my profie here if you're interested

A piccie of the blown component might help too

 

What I think I did wrong is when I installed a 240v to 24v transformer I wired it up the wrong way (polarity wise) if this is possible with ac as it has no polarity
I purchased a multimeter (shame on me for not using one in the first place ) and the reading has a minus sign when I test the secondary 24v

Craig

 

Thanks. So it is a 47V MOV.

This is used for protection against voltage surges. If you remove this component it will not affect the operation of the circuit. It is faulty if it registers with low resistance when removed from the circuit board.

Thanks heaps MrChips

Where can I get a new one or a substitute; I'll have a go at replacing it - need to learn sometime

 

AC does not have polarity. Reversing the leads would not damage the unit.
If you swapped the primary and secondary windings you would zap the board with 2400V.

 

Thanks heaps MrChips

Where can I get a new one or a substitute; I'll have a go at replacing it - need to learn sometime

Remove the component. If the board does not work you have another fault some place else.

 

Remove the component. If the board does not work you have another fault some place else.

Here is the back of the board with the component connections marked; do I need to jumper where I remove it to maintain the circuit and if so how;

By way of thanks MrChips. if you ever have a coding problem (from upper level - down to microcode level) please give me a bell and I will help
I am very experienced in all levels of coding from mobile apps to process/machine control etc. my email is on vandekamp.com.au

Just to humor me; if I wanted to replace it what component number etc would I use to do this?
I know you said it's not needed but I would like to get the PCB as close to what it was as I can
YES I'M A BIT OCD THAT WAY

 

If it is a MOV/Varistor it is a protection component and the board should function correctly (but sans protection) without it as MrChips says.

No do not put a link in its place. That would short something.

The question is why do you think it has failed, it does not operate in normal circuit action?

And if it has failed (It protects by failing) then what else went wrong?

 

If it is a MOV/Varistor it is a protection component and the board should function correctly (but sans protection) without it as MrChips says.

No do not put a link in its place. That would short something.

The question is why do you think it has failed, it does not operate in normal circuit action?

And if it has failed (It protects by failing) then what else went wrong?

I hooked up a brand new 250v Primary 24v secondary transformer turned it on and [SMOKE, SPARKS etc.] I instantly turned off the power.
I know it failed because once looking at the board I saw this (pic below) hard to miss huh
The reason for failure could be that the machine has been sitting in a warehouse for 25+ years unused so it may be just an age thing
I have other machines of the same type and age from the same place and they worked fine.
I am going to follow MrChips advice and remove it and then go through the whole circuit board to make sure it is clean as I can get it and all components look OK
Then I'm going to power it up again (fingers crossed)

 

Remove the thing and test the board. Do not jumper across because that creates a short.
Worry about sourcing the component later after you are happy that the board works.

 

I burnt out a component on the PCB of my 1980's Japanese pinball machine (known as a pachinko machine) and was wondering if anyone can give me some info on it ... (see pic)

its a 24 volt AC system and the component markings are:

470K 411(?) where (?) is either a 9 or a symbol

a). Tell me what it is and what its ratings specs etc. are?
(I think it's a Zener Diode as the PCB has ZD3 marked below it)

b). Where can I get a replacement

c). can I substitue another component for it.

thanks folks

Craig

Its a metal oxide varistor - IIRC: it loosely follows the standardise component value scheme, except it stands for voltage.

The first 2 digits are base value and the "0" is the multiplier - so I'd say its 47V.

Looks like the Matsushita trade mark on it, they probably have data/catalogues online.

Back in the early days of CTV, the first automatic degauss used a very basic 2-terminal PTC thermistor to produce the decaying burst of AC through the degauss coil - they had a problem that the residual current through the PTC energised the coil just enough to make the picture wobble.

The solution they found, was to replace the degauss coil with a load resistor and feed the coil via a 68V MOV, as the PTC reached working temp, the voltage dropped below 68V and the coil was cut off.

Those MOVs were very thin, but about 2" diameter.