another defender problem with voltages

bigdadnsir

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the go7 is dead.

have it going to a w4600 now. there is red sprites on the monitor and then there is rows of colors like red, yellow, and then a bunch of other ones. they are all even at about 1 inch wide.

started doing voltages checks. to the coin door off the power supply

pin 1 = -5.27
pin 2 = -5.4
pin 3 = 34. yepp that is what i said 34

here is the power outlet off the power supply

pin 1 = -4.93
pin 3 = 12.13
pin 4 = -15.95
pin 6 = 14.91
pin 7 = 14.91

pin 12, 13, and 14 = 4.96

voltages thru the fuses.

7asb = -4.2
7asb = -.3
4asb = 16
5asb = -5.3
1asb = -5.3

i am assuming power supply has totally gone bad. all lights are on for the power supply and for the rom board all 4.
thanks for any info.

might even be a great project for someone that has the parts to fix it.
 
I would check the power output of the transformer to make sure the correct input voltages are present. From the Defender schematics:

Lug 15 -> Lug 16 = 11.3 VAC (pin 3 to 5 on PS Input)
Lug 16 -> Lug 17 = 11.3 VAC (pin 5 to pin 1)

Lug 11 -> lug 12 = 20VAC (pin 8 to pin 9)

Lug 13 -> Lug 14 = 11.5 VAC (pin 11 to pin 12)

You should also test the voltages at the power supply board and at the MPU board. Those voltages should be:

MPU board power input pins:
1 = GND
2 = GND
3 = GND
4 = key
5 = +12VDC Regulated
6 = n/c
7 = +5VDC Regulated
8 = +12VDC Unregulated
9 = -5VDV Regulated

At the Power supply output pins:
1 = -5VDC Regulated
2 = key
3 = +12VDC Regulated
4 = -12VDC Unregulated
5 = +12VDC Unregulated
6 = +12VDC Unregulated
7 = GND
8 = GND
9 = GND
10 = GND
11 = GND
12 = +5VDC Regulated
13 = +5VDC Regulated
14 = +5VDC Regulated
15 = +5VDC Regulated

The regulated voltages should be +/- 0.2V of the specified voltages. Unregulated voltages are approximate voltages.

Make sure your voltmeter is set correctly when you measure AC voltages. You will get the wrong measurements if the meter is set to DC voltages.

AC voltages are measured between the two points listed. DC voltages are measured with reference (the black lead on your meter) to ground.


ken
 
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