Apollo 13 testing magnet coil with LCR meter

(Topic ID: 200189)

Apollo 13 testing magnet coil with LCR meter


By GTV6

1 year ago



Topic Stats

  • 9 posts
  • 3 Pinsiders participating
  • Latest reply 1 year ago by GTV6
  • Topic is favorited by 2 Pinsiders

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#1 1 year ago

Hello everybody,
After burning fuses and transistors on the A13, we tested the magnet coil. I measured 3,1 Ohm on the coil.
Then we tested with LCR meter and compared with the same coils in a friends LAH, the three coils in the LAH gave +/- 13.500uH while my coil from the A13 gave +/- 750uH. I am not very familiar with testing inductance, can somebody here confirm the coil was burning my fuses and transistor from the moonmagnet auxilary driver board?

#2 1 year ago

Usually when some coil is below 4 Omh is bad.

#3 1 year ago

Ok, new magnet coil installed. Magnet coil is constantly fully loaded in attract mode. Immediately when I close the coindoor I hear the magnet coil working, it receives 80V without any reason.
Already changed 4 times the transistor in the moon magnet auxilary board. (there was a P40NF10L installed that was broken, schematics says P20N10L, I used STP22NE10L) I found people on the forum saying to use IRL540, I only find IRL540N for sale. Cam somebody say witch is good, witch is better??
I'm turning around burning fuses, transistors and a magnet coil. I still don't know which is the symptom and which is the problem.
Somebody has an idea?

#4 1 year ago

This is from when I got my A13.

I copied and pasted form the thread I posted it should help you.

"I just purchased the game the other day

Should have gone thru it more before playing it for a awhile. Seller stated moon was melted but I didn't realize coil was locked on still should have checked.... Lesson Learned!

Since then, I have repaired the circuit for the moon and ordered new mag coil. The circuit is a very poor design, it goes thru the segment display board than to the aux driver than to the coil.

A VERY IMPORTANT THING TO NOTE IS THAT IF THE BLUE/WHITE WIRE ON J2 DOES NOT MAKE CONTACT THE MOON WILL LOCK ON. J2 USES A IDC CONNECTOR AND VIBRATIONS CAN AND WILL LOOSEN THIS WIRE OVER TIME!!!!!!!

To repair the circuit I had to fix the following (note this also repaired the 7 segment countdown display):

Bad components on 7 Segment Display Board:
------------------------------------------------------------
U2 - 74LS273 (if your moon works fine but countdown LED display does not replace this chip)
Q4 - 2n3906
Q5 - 2n3904
Q6 - 2n3904

Replace J2 IDC connector with molex connector.

Bad components on Moon Aux Board
-------------------------------------------------------------
Q3 - 20n10L replaced with IRL540 (NOT IRF540!!!!)
D10 - 1n4004
"

the components on the 7 segment display board control the moon as well you could have a bad Q4, Q5, or Q6 on that board. check with logic meter this document will help you with that.

http://arcarc.xmission.com/Pinball/Stern%20Service%20Bulletins/sb/sb80.pdf

#5 1 year ago

Very interesting.Will save this like usefull info.

#6 1 year ago
Quoted from arakissun:

Very interesting.Will save this like usefull info.

No problem

Thanks for the moon mech I bought from you! Was able to replace my melted one

#7 1 year ago

Thanks for your answer, I already saw your post and already changed Q4, Q5 and Q6 like in your post. Countdown display does work.
I doublechecked the Blue/white wire is making contact from board to board. Q3 replaced already 5 times by STP22NE10L, because I had some. I want to buy IRL540 but only find IRL540N.
Should they work too?

#8 1 year ago
Quoted from GTV6:

Thanks for your answer, I already saw your post and already changed Q4, Q5 and Q6 like in your post. Countdown display does work.
I doublechecked the Blue/white wire is making contact from board to board. Q3 replaced already 5 times by STP22NE10L, because I had some. I want to buy IRL540 but only find IRL540N.
Should they work too?

you need to check the output on U2. If you replaced everything else check U2 is likely bad.

Also when you replaced Q4 - 6, did you verify pinout on some replacements it is different.

#9 1 year ago

I was thinking U3, because I have no problems with the 7 segment display. How can I check this components?
I verified Q4-6, the gave the same values on same pinout like the old ones.

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