home

CPU
cpu

Fehlersuche
troubleshooting

Clock
clock

EPROMS
eproms

Video / ESS
video / ess

Sound and voice
sound and Voice

contact
contact

power supply
power supply

links
links

you are herepower supply


The PP7A power supply


Cocktail Table Example

PP7A power supply PP7A is a switching power supply located in a metal box on the left side of the monitor. This picture shows the cocktail table version of Radar Scope and the arrow points to the PP7A located behind the coin box.
6P ESS and 7P SOU The 6P ESS and 7P SOU plugs are on the back side of the box. Seen from the solder side, you will have the two GND pins of the 6P ESS on the left as in this picture
text

On the top of the plug you can check voltages by applying the probe during attract mode. In a working game they were, for example: 4.83 V (low by 3.4%) / -5.07 V / 12.04 V / 23.33 V
The voltages should not be off more than 5%


+5 Volts @pin
6P-4
6P-5
7P-6
9P-6
9P-7
10P-9
10P-10
-5 Volts @pin
6P-6
7P-7
9P-8
10P-1
10P-2
10P-3
10P-4
+12 Volts @pin
6P-3
7P-5
9P-4
9P-5
+24 Volts @pin
9P-9
Ground @pin
7P-1
7P-2
10P-5
10P-6
10P-7
10P-8

Replacing a PP7A power supply

If you have a defective power supply and you cannot repair it you can replace it by using two switching power supplies, one for the +5 and the +12 volts and another for -5 Volts.

The reason for the necessity of two supplies is that the CLK board with its ECL logic draws a large current of several amperes at -5V.
The original power supply has the following specs

+5 V DC  up to 7.5 A
-5 V DC  up to 6.5 A
 +12 V DC  up to 100 mA
 +24 V DC  up to 200 mA


The 24 Volts are being used for the game counter and can be omitted if necessary

A very good replacement for the PP7A power supply are two PC power supply units from old PC's. For example, I have used two identical Magnetek power supplies which are too weak for modern PC's (having only 65 W per unit) But they can be used as a Nintendo replacement PP7A without problems

You will have to wire them in the following way:

ESS power input

ESS power in This is the edge of a TRS-02-ESS board, showing the P2 POWER IN connector from the component side. PINS 1 and 2 are GND, 3 is +12V, 4 and 5 are +5V, 6 is -5V. See also in the video section.
Backside of the same board. The jumper cable on the solder side is on PIN 3 (+12V). Note that in the schematics (PDF) of the ESS board the pins are numbered in mirrored fashion (which is an error).