(Topic ID: 171853)

LW3 dmd fuse blows 1 in 5 times when turned on

By Pmuis

7 years ago


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  • 16 posts
  • 4 Pinsiders participating
  • Latest reply 7 years ago by Pmuis
  • Topic is favorited by 2 Pinsiders

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520-5047-01 PS DE LW3.jpg
xform hi-volt.PNG
Untitled (resized).png

#1 7 years ago

Hi people,

I'm repairing a leathal weapon and ran into a problem which I can't seem to figure out. The problem is when I turn on the pinball I see the fuse glow like it blows, yet it doesn't blow all the way trough. Its directly when turned on and directly after it stops glowing and de dmd works fine. You see the fuse get weaker and after a few times the fuse blows completely. I pulled cn5 off the board and after it still happend so I thought it was the HV section. I ordered and placed a repair kit which included the big resistors, (zener)diodes and transistors. Yet the problem is still there. Has anybody had the same problem of does somebody know what could be problem?

Thank you in advance

#2 7 years ago

Fuses are not supposed to glow. Which fuse is it? Is the the correct value fuse? Sometimes people but in the wrong fuses, or even cartridge lamps (just because it looks like a fuse).

#3 7 years ago

No I know. Its the correct fuse. What I mean is. It looks like the fuse blows, but it doesn't burn through. Like its getting a peak power at the machines start up. replaced the fuse a few times allready. Slow blow 0.5 amps.

#4 7 years ago

Which fuse is it? F1, F2, F3, etc.

#5 7 years ago

Fuse F7 on the power supply
0.5 Amp Slow Blow
Display reg. Input 90VAC

#6 7 years ago

this drawing is kind of confusing. Where does the CN1X12 Pin 7 go?

Untitled (resized).pngUntitled (resized).png

#7 7 years ago
Quoted from barakandl:

Where does the CN1X12 Pin 7 go?

To the transformer. the 'neutral' lug is fused here.
xform hi-volt.PNGxform hi-volt.PNG

edit:
seems the manual or my pic is wrong so verify the connections

#8 7 years ago

Exactly. Thank you for replying everybody. I will try to add a thermistor tomorrow since data east is sometimes known for having peak powers at startup which can blow your house fuse but I don't know whether it will apply here as well. But that is the problem I'm having. Some kind of peak power when you flipp the switch on (I think) it happens to fast to measure and probably not the savest.

zaza & barakandl
I believe that there isn't a 90v. Thats there for alpha numeric displays. The power enters at cn1-9 and runs through the fuse back to neutral through cn1-7. (I think)

Edit:
I think I'm wrong about that. Input at cn1-9 is for negative voltage I believe.

Edit Edit:
Now I'm confused. In the manual pinout diagram for cn1 on powersupply it says that cn1-4 is connected to ground aswell

#9 7 years ago

There are different configurations (alphanumeric/dotmatrix: smal/large ) of this CN1 .
As far as I know is CN1-9 fused to GND and the other wire CN1-4 and CN1-7 supply for display hi-voltage.

I need to verify this when I repair a DataEast machine.

#10 7 years ago
Quoted from Pmuis:

I pulled cn5 off the board and after it still happend

Quoted from Pmuis:

placed a repair kit which included the big resistors, (zener)diodes and transistors.

The capacitors C10 and C11 are the next suspect.

(I'm not sure about the internal wiring of tranformer so there's a question mark placed)

520-5047-01 PS DE LW3.jpg520-5047-01 PS DE LW3.jpg

#11 7 years ago

Thank you zaza. I'm going back to work on it in an hour and I'll change those caps. I will let you know whether that helped.

#12 7 years ago

Zaza!! Worked. Thanks man. There were 220 uF capacitors on the board which could have helped with the problem. Replaced them with 150 uF 400v caps and it worked. 400v was the only thing they had at the store.

#13 7 years ago

Great !
So the 2x 220μF was too heavy for the 0.5Amp fuse to charge them during startup.
Higher capacity capacitance is not always a good thing then.

#14 7 years ago

Yeah that was probably the case. I could measure the capacitors to see whether they failed in any other way. But it could be the case. Yet it looked original.

Edit: *I couldn't

#15 7 years ago

Capacitor failing high ESR?

#16 7 years ago

So, I don't know what exactly caused the problem. The problem was completely with the caps since after installing it the problem was solved. For futher reverence

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