QBERT, installed the arcadeshop power conversion kit, and now the knocker isn't....

tron guy

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QBERT, installed the arcadeshop power conversion kit, and now the knocker isn't....

getting enough power or knocking loud enough.

couldn't get any help from Steven at arcadeshop, he is dumbfounded that this doesn't work.

The knocker was either rebuilt or new (got it from riptor about a year ago) I think it was new.

I am getting +12.16 or so on my plus 12 at the power supply.

put the old power supply board back in (100% working board) and it knocks perfectly again.
 
i believe these power supplys only supply 12v to the knocker don't they? i didn't see the 24v i thought it was supposed to supply at all. my knocker works but i think its only getting 12v and is very weak sounding.
 
i believe these power supplys only supply 12v to the knocker don't they? i didn't see the 24v i thought it was supposed to supply at all. my knocker works but i think its only getting 12v and is very weak sounding.

yeah I guess mine "works" as far as being functional. But it doesn't "knock" it hits like a marshmallow falling onto a feather pillow.
 
This was my fear in getting one of these kits, that the knocker would be soft.

What about the sound? No abnormalities there?

I may still get one of these kits, but am wondering if it would be hard to find a 12VDC solenoid to replace the original coil?
 
You should have researched it a little, there are multiple threads on the knocker not working with the switcher. I was working (testing) switchers on qbert before arcadeshop came out with theirs. I scrapped the idea when I realized the knocker didnt work right with the switcher.
The switcher provides 24v to the knocker, not 12v. The original linear is 30v and in most cases is around 32v. The sound amp functions perfectly at 24v and even as low as 14v but the knocker is another story.
Im still not against putting a switcher in them but if your concerned with the knocker working correctly then the switcher is not the way to go.
Some people argue that they used the same knocker in some pins that run off 24v fine. True but they are using a linear supply and I think the problem is not so much the voltage but the current the switcher can provide. Im no expert but I did spend alot of time playing around with these before finally deciding it was not worth the effort.
Some people say their knocker works fine with the switcher but I wonder if they know what its really supposed to sound like.
 
because I do not know.............
you say the switcher provides 24v to the knocker. I suppose that little conversion power board increases it to 24?

Are there any other tricks? possibly using a second switcher dedicated only to the knocker to get it more power?
 
You should have researched it a little, there are multiple threads on the knocker not working with the switcher. I was working (testing) switchers on qbert before arcadeshop came out with theirs. I scrapped the idea when I realized the knocker didnt work right with the switcher.
The switcher provides 24v to the knocker, not 12v. The original linear is 30v and in most cases is around 32v. The sound amp functions perfectly at 24v and even as low as 14v but the knocker is another story.
Im still not against putting a switcher in them but if your concerned with the knocker working correctly then the switcher is not the way to go.
Some people argue that they used the same knocker in some pins that run off 24v fine. True but they are using a linear supply and I think the problem is not so much the voltage but the current the switcher can provide. Im no expert but I did spend alot of time playing around with these before finally deciding it was not worth the effort.
Some people say their knocker works fine with the switcher but I wonder if they know what its really supposed to sound like.


I can't remember but I think the standard way to mount the knocker is so the plunger shoots upwards and pops.
Is it possible to mount it sideways so it doesn't have to fight gravity so much?
(I don't have the machine here, so I can't look at it right now)
 
The switching power supply works fine with the knocker, its just knocks a lot softer than with the original power supply. I have one in mine and doesn't really bother me that much. Its actually makes a little more sense in some regard that the knock is softer. You have the little snake that falls off the side that should make a little sound. Instead with the original power supply the knock is very loud as if it was a Elephant that fell off the side. Either way as long as the knocker is working its up to the owner how loud they want it to sound.


getting enough power or knocking loud enough.

couldn't get any help from Steven at arcadeshop, he is dumbfounded that this doesn't work.

The knocker was either rebuilt or new (got it from riptor about a year ago) I think it was new.

I am getting +12.16 or so on my plus 12 at the power supply.

put the old power supply board back in (100% working board) and it knocks perfectly again.
 
That's weird. When I had my switcher installed, in addition to the soft knocker, the sound was slightly distorted. I didn't notice the distortion at first, but Gene at Vintagearcade pointed it out. Once I realized it, it bugged me. I've gone back to using the original power supply and like it much better.

Tom

sounds are good.
 
because I do not know.............
you say the switcher provides 24v to the knocker. I suppose that little conversion power board increases it to 24?

i'd like to know this as well...i dont see how its getting 24v when the switcher only has outputs of 5 and 12...

it even says on arcadeshops site that 12v is used for sound and knocker.

http://www.arcadeshop.com/gott-ps/gott-ps.htm
 
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I might be wrong, I thought the AS switcher outputed 24v as well. Anyways, the ones I have do and the 24v was not enough. I can imagine 12v would work at all. Yep, looking at the pic on the AS website its just a standard HD switcher with 5 and 12.
Tron Guy, you cant mount the knocker sideways because the plunger wouldnt return.
Fatherpain, I know for a fact that the LM379S will operate perfect WAY below 30v. There is one cap on the sound board that is notorious for going bad, you might just have a bad cap. If you check the datasheet for the LM379S you will see that the max input voltage is rated at 30v. The amp on these are running right at or above the max voltage specification. Im not sure but I think it specifys something like 18-30v on the datasheet.

You could always just run a standalone 30v PS and use the 12v to switch a relay to send it to the knocker.
 
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that's it then, I suppose you learn to live with it or go back to the original power board.

no response from arcadeshop. guy acts like a know it all, but unfortunately for him, he doesn't.
 
Something I would try but don't have a working q*bert to test. Maybe someone could double check my calculations or test this please let us know. Q*bert uses a A-5195 coil. Two things you could do.

1. Take the wrapper off the coil. Desolder the outer winding and un-wind about 50 turns. Check the resistance and that point. Don't go below 5 ohms. Resolder the winding back on. This will lower the resistance and make the coil "more powerful". We do this in the pinball world all the time.

2. According to my calculations, the current draw through the coil circuit is about 2.5 amps. Now, it's only protected by a 1A sloblo fuse (it can handle that for a fraction of time, that's why it doesn't blow for a coil). The transitor that fires it is a 2N6044. It can handle 8A. Looking at the A-5195 coil, it has a resistance of about 12.3 ohms. Under the normal 30v, that where I get about 2.5amps. A gottlieb A-5194 coil only has a resistance of 4.5ohms. That will give you about 2.6amps with the switcher only supplying 12v. If it blows the fuse, which it shouldn't, use a 1.5amp slo-blo. The extra can easily be handled by the 2N6044 (8A) and the switcher 12v which looks like it can handle 4A.

#2 is the way I would go. No hacking involved and can easily be documented and put back to the original state.
 
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