Anyone Know what this is and where I can get one

ian field

Joined Oct 27, 2012
6,536
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 :p
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)

My theory is; that part is/was a 47V MOV - once they fail, they can disintigrate even if you don't apply excessive voltage.

Find a MOV that's rated for mains voltage and fit it across the transformer primary as temporary protection from spikes - remove what's left of the damaged part and measure the voltage across its pads.
 

ian field

Joined Oct 27, 2012
6,536
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
View attachment 85884

cheers and thanks again for the help

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

The black square the part is next to looks like a bridge rectifier - if its fed 24VAC, my theory that its a 47V MOV is probably correct.

I wouldn't reccomend any substitutions, but its probably a *LOT* easier to source mains rated MOVs than such a low voltage part. At least a mains rated MOV across the primary would be better than nothing - but I'd still keep looking for the right part.
 

Thread Starter

CRAIG VANDEKAMP

Joined May 14, 2015
20
Last edited:

ian field

Joined Oct 27, 2012
6,536
I was just looking around to source a suitable replacement and came across these; What do you think?

http://www.westfloridacomponents.com/VR008PD/ZNR Transient Surge Absorbers ERZ-VO5D470 125A 47V.html
http://au.rs-online.com/web/p/metal-oxide-varistors/7606917/

Any suggestions on what specs I should be looking for?

I'll keep looking

cheers

Craig
Panasonic is a name used by Matsushita - which is what I think your original is/was.

Get the measurements and look for one the same physical size/mass.

An MOV takes a hit every time it stops a spike, so they don't last forever. A bigger part will absorb more punishment before failing.

A mains rated MOV on the primary would also soak up some of the potentially destructive energy that can come along. A local store had some mains plug MOV packs with no lead from them or receptacle you can plug anything else to - they simply function as a spike clamp on a socket somewhere on a ring main. An additional primary side MOV would afford some small protection for anything taking mains nearby on the same circuit.
 

KJ6EAD

Joined Apr 30, 2011
1,581
You should be able to get an appropriate replacement part in Australia, possibly from Jaycar or Element14. There"s no need to buy it from a Florida surplus dealer and pay enormously for shipping.
 

ian field

Joined Oct 27, 2012
6,536
This one looks like it would do the job; any opinions?

mains voltage is 240V AC

input voltage is 24v AC

circuit load is 24V AC 3A 100VAC

http://au.rs-online.com/web/p/metal-oxide-varistors/2896774/
That part can only be used on the secondary side at 24VAC - and its nearly twice the clamping voltage of the original, so it won't provide as much protection.

A suitably mains rated part across the primary would be better than nothing, but I'd keep looking for the right voltage part for the secondary.

As I mentioned elsewhere; you can use a bigger part as long as the clamping voltage is correct.
 
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