Tech: Apollo 13

jfruge

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Guys, I have a Apollo 13 that started blowing the A7 fuse. I don't
have the manul and I did look for it online but could only find the
small under 3meg watered down version. It was just blowing every now
and then. It has now changed to blowing as soon as I close the coin
door. When this fues blows it will no longer put a ball into the
shooter lane. I also think this fues is tied to the big rocket (moving
up and down).


I have never had to work on a Sega before. Any ideas on what to look
for would be super helpful.


Thanks,
 
Opening the coin door shuts off the power to the coils. The fuse must go to one or some of the coils, which would explain not ejecting the ball in the shooter lane after it blows.
 
Looking at the manual from IPDB, it looks like the 7A(F6) fuse feeds diode bridge#1 which is your 50v for your coils. Does the 5A (F21) fuse blow as well? If not, I would replace diode bridge#1.
 
Looking at the manual from IPDB, it looks like the 7A(F6) fuse feeds diode bridge#1 which is your 50v for your coils. Does the 5A (F21) fuse blow as well? If not, I would replace diode bridge#1.

I think I gave the wrong fues # I said A7 but ment to say F7.

FYI,
 
I got some time to do some troubleshooting. I put it in single coil test mode and tested each one. The first bunch worked fine but then I found some that were not doing anything. Also It did not matter what coil was being tested if I closed the coindoor interlock the F7 fuse would blow. Also if I tried to test one of the non working coils during the 3 seconds it takes for the fues to blow it still did not fire. I also got an email with a lead on the full manual download so I got it now.
Still looking for what to check next. Any input welcomed.
Thanks,

John Fruge
Madera, CA
 
According to pinrepair :)

F7= 3a slo-blo +32 volt for playfield coils/flash lamps Right/Left.

Have you visually inspected all of your flash lamps looking for shorts? Have you checked your low voltage coil diodes and put a meter to the coils themselves?

"
A very good idea for any unknown game just purchased is to check all the coils' resistance. If the game is new to you, and you have not powered it on, a quick check of coil resistance will tell you a lot about your new game. This takes about one minute and can save you hours of repair and diagnosing work.
Any coil that has locked on (usually due to a short CPU board transistor) will heat up and have a lower total resistance. This happens because the painted enamel insulation on the coil's wire burns, causing the windings to short against each other. This will lower the coil's resistance, causing the coil to get even hotter. Within a minute or so the coil becomes a dead short (less than 2 ohms), and usually blows a fuse.

If the CPU board transistor is repaired, and the game is powered on with a dead-shorted coil, this will blow the same driver transistor(s) again when the coil is fired by the game for the first time! There is no sense making more work for yourself. So take 60 seconds and check all the coils' resistance BEFORE powering the game on for the first time.

In order to check coil resistance, put your DMM on its lowest resistance setting. Then put the DMM's red and black leads on each coil's lugs. A resistance of 2.5 ohms or greater should be seen. Anything less than 2.5 ohms, and the coil and/or driving transistor may be bad. Now remove the wire from one of the lugs of the coil, and test the coil again. If the resistance is still the same (low), the coil or diode is bad (and also perhaps the driving transistor). If the resistance is higher than 2.5 ohms, the coil is good but the solenoid driver board transistor is shorted and will need to be replaced. Lastly, the coil's 1N4004 diode could be shorted too, giving a false low coil resistance. Cut one diode leg from a coil lug and retest the coil's ohms.

Remember when reconnecting the wires to the coil that the power wire (usually two wires or thicker wires) goes to the coil's lug with the BANDED side of the diode attached. The thinner wire is the coil's return path to ground via the driver transistor and attaches to the coil lug with the non-banded side of the diode attached.

If a low resistance coil is found, also suspect the associated CPU board transistor as bad. A low resistance coil is a red flag, a warning, that there may be problems on the CPU board. Actually with System11 games, if a low resistance coil is found, I can pretty much guarantee that you will need to (should) replace of course the coil, but also all the silicon devices in its ground path (TIP driver transistor and probably the pre-driver transistor).
"
 
Update

Rob on RPG said to try this:
*********************************
Pull J6 and J7 from the driver board one at a time to see which might be
causing the fuse to blow.
If J6 is the one the causes the fuse to blow, you have a shorted flasher
socket/bulb somewhere in the game. If it's J7, then one of the low power
solenoids is causing it, probably a shorted coil/coil lug/diode.

If pulling both J6 and J7 still has the fuse blowing, then BRDG2 is likely
bad.

--
Rob
**********************************
Here is how it turned out :

I did the tests you called out above. With both unplugged the fuse is
fine. With J7 installed the fuse is also fine. With J6 installed the
F7 fuse blows.
I will start looking at the "flasher socket/bulb" area's and see what
I come up with.

Thanks again,

Also just a note: I was able to play some games with the flashers
unplugged and all seems fine Ya! :)
 
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