(Topic ID: 230716)

Rescue 911 voltage issue


By whizz

5 months ago



Topic Stats

  • 17 posts
  • 4 Pinsiders participating
  • Latest reply 5 months ago by whizz
  • No one calls this topic a favorite

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#1 5 months ago

All voltages at the transformer panel are correct at the transformer panel when fuses f4 thru f11 are removed,so I think my transformer is good.I have replaced both caps and all 3 bridges.When fuse f7 is put back in I am getting 69vdc to my coils.My schematic shows it should be 48vdc.The game did play but now it just has GI.Will not go into attract.I can't understand how 50vac to the bridge puts out 69vdc.I have looked at all wiring and don't see anything odd.There are no hacks on any wiring.Does anybody have any ideas.Thanks

#2 5 months ago
Quoted from whizz:

All voltages at the transformer panel are correct at the transformer panel when fuses f4 thru f11 are removed,so I think my transformer is good.I have replaced both caps and all 3 bridges.When fuse f7 is put back in I am getting 69vdc to my coils.My schematic shows it should be 48vdc.The game did play but now it just has GI.Will not go into attract.I can't understand how 50vac to the bridge puts out 69vdc.I have looked at all wiring and don't see anything odd.There are no hacks on any wiring.Does anybody have any ideas.Thanks

This will be perfectly normal. The voltage is not regulated and therefore it will sit higher than the specified value.

Read up on it at many sites - one here:

http://www.bristolwatch.com/ele/basic_ac_rectification.htm

#3 5 months ago

Before I changed the bridges I only read 29vdc.I am sure the wires are correct.Same part # bridges.

#4 5 months ago

That seems about right. incoming a/c times ~1.4 = 70 vdc

#5 5 months ago
Quoted from whizz:

Before I changed the bridges I only read 29vdc.I am sure the wires are correct.Same part # bridges.

Maybe the original bridges were faulty? In any case, as OCD_pinball above also suggests, this is about right.

Your problems are likely to be elsewhere.

#6 5 months ago

So is the schematic wrong.It shows the voltage should be 48vdc.

#7 5 months ago

What are your 5 volt readings at on your small power supply?

#8 5 months ago
Quoted from whizz:

So is the schematic wrong.It shows the voltage should be 48vdc.

The schematic is likely correct. This voltage is a 'nominal' voltage on the schematic. Unless you are trained in electronics you won't understand this that's why I linked to a site so you could learn about it.

#9 5 months ago

I will double check my 5v.yesterday it was 5.1.I have experience in electricity,little in electronics.Thanks

#10 5 months ago

My 5v output is steady 5.2v.My display has part of bottom line out.I have ordered a new one,but while checking found previous owner had installed 10amp fuse.Schematic says it should be 3/8 amp.Could display cause this type of problem?Thanks

#11 5 months ago
Quoted from whizz:

My 5v output is steady 5.2v.My display has part of bottom line out.I have ordered a new one,but while checking found previous owner had installed 10amp fuse.Schematic says it should be 3/8 amp.Could display cause this type of problem?Thanks

Yes....sort of... Your display driver and CPU board need to boot and talk together for the rest of the machine to work. 5.2 is a little high, but not out of spec. You said the game worked before? If it worked before, why did you change out components, or what were the problems with the game previously?

Do the red lights on the cpu and the display driver board above it flash, or are they solid?

#12 5 months ago

I changed the components when I had the transformer panel out to clean it and install new power cord.The game was real dirty in the cabinet.I did not want it in the house that dirty.Thanks

#13 5 months ago

All the boards flash.

#14 5 months ago

Do you get two audible beeps when you power on the machine?

If not, Lets try this...since it was working before.....

Turn game off.... Remove top connector from the small power supply board. Put a meter on the output of that board and then power game on (With meter connected to output). Adjust the trim/pot on that board until you get your meter to read at 5.0 or just slightly above it (not up to 5.1 though).

Then, turn game off, remove meter, put connector back on, and then turn game on.

These games are really picky about their 5 volt. Replacing the big caps may have given it enough juice to be slightly out of spec.

#15 5 months ago

Ok,That worked.I trimmed the voltage to 5v.The game powered back up and plays again.I seem to have an issue with C relay.I am going to check it out.Thanks

#16 5 months ago
Quoted from whizz:

Ok,That worked.I trimmed the voltage to 5v.The game powered back up and plays again.I seem to have an issue with C relay.I am going to check it out.Thanks

Cool... congrats... if you need any other help, just post it...

#17 5 months ago

Thanks,I appreciate all the effort.

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