After changing to the PinLED Displays there is some noise/hum coming out of the speakers
I
This effect can come about after installing the PinLED Displays. As far as we know this only happens with Data East machines. The Williams pinball machines exhibit these symptoms only very seldom. In the around 5 % of the Data East machines where these symptoms come about these symptoms can be cleared.
How does this effect come about ? The 5 Volt power supply of the pinball machine converts an ac voltage to a dc voltage. This voltage is then smoothed by a large capacitor before it enters the voltage regulation circuit. This smoothed voltage can then be set to +5 Volts by the following regulator. All circuit boards of the pinball machine are then supplied with +5 V. As the boards are now supplied by the regulation circuit, the amount of smoothing needed to be done by the capacitor becomes less. The load on the regulation circuit is increased by approx. 1 A due to the connection of the PinLED Displays which results in an increase in the ripple voltage. This can lead to a 100 Hz hum in the loud speakers (but not necessarily).
How can I get rid of this effect ? Electrolytic capacitors are subject to a certain aging effect. They eventually dry up after a few years. This leads to a loss in capacity. A capacitor having a capacity of e.g.1000µF would then have less than this after a few years. During their operating lives capacitors are exposed to warm air temperatures, which brings about and accelerates this aging effect. The following measures can reduce this effect:
Replace the filter capacitor in the +5 Volt regulation circuit. Ideally with a capacitor with a slightly higher capacitance value.
It is possible to connect one or many capacitors in parallel with the filter capacitor. Here you can choose a capacitor having the rating of e.g. 4700µF / 25 Volt. Please choose a capacitor having a rating of at least 25 Volts.
Further, a ferrite ring can be connected at the input to the sound card. The power supply, speaker and ribbon cable is then wound 2 times through a ferrite ring having a diameter of between 3 and 4 cm.
The same thing can be done with the cables that lead to the PinLED Display (use a second ring for this!).
Should this problem come about, and the suggested solution still does not work,
please contact our Support
go back