SS Pistol Poker (Alvin G, 1993) speakers swapped around... or something

[GreenLED]

OK, so a HUGE thanks (and recommendation) to Clive at the Coin-op Cauldron for getting my Alvin G Pistol Poker power supply working right. Now I'm still fighting the DMD issues, but I want to solve another mystery. For some reason, the left speaker works fine, but it seems the right and cabinet speaker wiring is switched. I've checked, and can't find anywhere wiring has been changed, and the color codes match clear from the board to the speakers. It's like the board itself is wired backwards, not that it's possible. Anyone ever heard of something like this? I'm guessing I just need to cut and splice them to swap them so they're right...

 

[wbwill]

Speaker issue

I am new as new can be to both forums and pinball machines, but I am not new to speakers, and I cannot imagine there is anything different about pinball speakers than everyday amplified speakers,

So for what it worth, I would offer this, before I would go cutting wires, I would get an ohm meter and measure the speaker ohm readings, if they are shorted, one speaker shorted will effect the other,

Another test I would attempt [either test being first matters not] is to remove the speaker wires from one of the bad sounding speakers, isolate the wires [note the polarity or color coding], take off both wires from either bad sounding speaker and test, if the sound improves it may well be a blown speaker, however unless you have a diagram, we won't know how the speakers are connected to the amp by the OEM to obtain the proper overall impedance matching [but don't worry with that yet, I have more info below if you need it]

So those would be some easy tests and no cutting of the wires.

My guess is also that because everything is color coded, there will be no need to cut any wires, next you can use your VOM to measure the amp output voltage and resistance, but it can made really complicated also,

I have personally trouble shot many amps and speakers, although it is not really what I do, so I hope this will be a help to you,, first an answer TO a very long and well written speaker testing comment:

Trying to keep this simple because speakers are not a straight resistive animal, like measuring a resistor, they are like trying to measure any kind of IMPENDANCE which usually takes a signal generator, scope and all that, so here is the short answer :

"Why not be simple? Speakers typically come in specific flavors, 2ohm, 4ohm, 8ohm, 16ohm.

Measure the dc resistance with your cheapo radio-shack ohm-meter, and round up to the nearest reasonable value. if you measure 14ohms, that's a 16 ohm speaker. If you measure 3 ohms, that's a 4 ohm speaker.

An electrical engineer with access to a signal generator and the knowhow to set up a full accurate test bench isn't going to be asking how to measure speaking impedance on a diy website..."

Here is the address for the whole in depth testing IF you want it:

http://www.fixya.com/support/t174447-measure_speaker_impedance

We are looking for one of two things, either a short in the speaker or wiring, or a short or issue in the amplifier,

So first isolate each speaker, keeping the wires taped off, this is the simple method, as you can see if it cleans up the sound of the other speaker, that speaker is bad and can be further checked and proven bad with an ohm test,

Now go to the next speaker, and do the same thing, if it is isolated and no help, then if further proves the first speaker is bad, 3 points of proof,

1 The ohm value should show way off the rating, 2 removing the speaker improves the sound of the other speaker 3 isolating the other speaker provides no improvement

Now if removing any speaker improves nothing, we need a voltage test on the output of the amp, which is tricky, as it is generally way down in volt range and most meters are not going to be that accurate, but if you read through the link, you will get some ideas on voltage measurements, and what meter to use, and how,

Finally hear is another site which does not get way complicated and might answer anything I have not covered above:

http://www.prestonelectronics.com/audio/Impedance.htm

My email address is supposed to be visible, but no knowing all the forum rules yet, I am not sure if I can put in on here, but I would have no problem helping you out that way, although by doing it through this kind of venue, it might help the next guy, but if you see my email and feel the need to write and ask, please do, I volunteer on allexperts.com, absolutely free help site, I get nothing for taking questions on it, right now it is marked vacation, because I have so many issues to deal with, I had to cut off the site for a while, if I would allow it I would get 10 or 20 questions a day, great site and anyone on there can help with electrical or electronic, mechanical whatever

I am hoping I am helping here and placing this in the correct spot, never using a forum, at least for much of anything, there is a LOT of choices and menus, so I am sure someone will monitor and let me know if I am too long or in the wrong place, but for now, someone helped me and I really want to return the favor, so excuse the length, but I just see no reason yet to start swapping and cutting wires, yes things can be perfectly color coded and wrong, but that is longest odds, so start with less destructive testing first, and we should be able to get this figured out without cutting and splicing wires, all you can really do is change polarities, look at the last link I put on here real quick you will see the amp is putting out voltage in parallel so swapping wires can be done by reversing polarities, but for now I would assume the color coding is correct, and you have a short some place, let me know how it goes, Will