Still have Hum

[Rhoward]

I have a Sammy "Super AT" with a 2 prong power cord. I installed an L-Pad and the volume can be controlled but the hum is still there. I reversed the power plug and even connected to a battery UPS with the hum remaining. Does anyone have a fix.

Thanks for the inputs. I didn't know I had 3 speakers. The humm is coming from the speakers. I would like to get a schematic of the power supply to add a filter to it. I can't read Japanese.

[Tulsa]

Now there's one I've never heard of, a Super AT?

Anyway, all my Sammy's have three speakers, two in the top and one for bass in the bottom. Do you have volume controls on all of them? If so and this didn't eliminate the hum, are you sure the hum is coming from the speakers?

[gwarzin]

A couple of things to check:

Does it have a transformer? If so, could it be a mechanical hum from the transformer instead of coming through the speakers?

Do you have the 3 postions volume switch all the way up? I've had to do that on some machines. In effect, you are turning the volume all the way up with the switch, then lowering it with the L-Pad. Of course, this only works if the hum level is independent of the setting of the volume switch. It did work for me on a YERY loud hum on a Thunderbird.

I do have on Sammy where the hum is a cooling fan on the video display. Nothing you can do about that.

[huffb01]

Tulsa,
I think the model that is being discussed it the "Gold Animal King" in the museum listings.

All,

The hum is pretty nasty on those, I think it is caused by the power supply for the fluorescence bulbs is on the same circuit board as the audio. So turning down the volume to the top speakers should help reduce the noise the most. However I don't see the hum disappearing totally

[arbycoffee]

Some Sammy's never get rid of all the hum, no mater what you do.

[slothappy144]

in automotive steros that hum is caused by AC noise on the DC power line. A noise choke on the DC power line (coil in series cap in parallel) quiets most of these hums, don't know where you would install this on a Pachi though. it is designed to dampen ac, so it would have to be a pure DC power feed to the audio circuit.

[musky]

I believe the hum to be coming from inductance produced in the florecent light fixtures getting into the audio wiring/circuit. As the light circuits get older they get "dirtier" and start causing the hum problem. Seem it happen in other applications and probably happens with pachis too. Think I'll follow up on it and see what happens

[dormi]

It hums because it doesen't know the words

[dishpan]

A common problem I have when singing in Japanese.