Knocker troubles

[felixthadog]

I checked my TZ last night and found that the knocker assembly in the backbox doesn't work. I went through all the Tests and Adjustments but could not find any reference to the knocker assembly. I set the Match level to 50% and played a few games until I got a Match, but the knocker didn't fire. I also ran the ball around the playfield manually until a Replay was awarded, but again the knocker didn't fire.

Here is a pic of the inside of the backbox, you can see the knocker assembly in the top left of the pic:



Here is the Solenoid table from the manual showing the connections for the Knocker:



I have checked the connections to J130 and J107 on the Driver board and they seem OK.

Here is the Driver Board pic from the manual showing the J130 and J107 connections that the Knocker should be wired up to:



It all seems fine to me, yet the knocker is not working. Is there a way to manually get the knocker to fire, for example by applying power to it somehow?  Is there a way of testing that the wiring to the Driver board is OK? 

Matthew

[goodolddays]

Gday Matthew .. I assume these newer games are the same as the old EM's .. in which case try a 9V battery across the coil .. probably best to disconnect it from the game 1st ?

Rgds
Dave

[felixthadog]

Gday Matthew .. I assume these newer games are the same as the old EM's .. in which case try a 9V battery across the coil .. probably best to disconnect it from the game 1st ?

Rgds
Dave

Thanks for the suggestion Dave, however I am a total n00b so I will need a little more detail than that  How do I try a 9V battery across the coil? Do I run some wires from the coil to the terminals on a 9V battery? And how do I disconnect the coil? 

Matthew

[Strangeways]

Start off by checking that the plunger can move freely.

Check the connectors are not tarnished
Check that the wire is pushed in on the respective IDC connectors (J130 / J107)
Check Q68 visually - does it look ok ?

[goodolddays]

Ah .. the Guru has spoken .. I'll leave you in his more than capeable hands 

[felixthadog]

Start off by checking that the plunger can move freely.

Check the connectors are not tarnished
Check that the wire is pushed in on the respective IDC connectors (J130 / J107)
Check Q68 visually - does it look ok ?

1) The plunger moves freely, no resistance at all in the movement up and down.
2) Do you mean the connectors on the Driver board or the connector near the coil? And by tarnished, do you mean burnt or just discoloured?
3) I reseated the connectors on the Driver board and made sure they were pushed in fully.
4) What is Q68?

Matthew

[Strangeways]

Matt -

The IDC connectors on the Driver board are notorious for developing faults over time. Moreso for high current applications like General Illumination, but on the occasion, even switch matrix IDC connectors can develop issues.

If you look on the two connectors you have highlighted, you will see the wires are "prized" into the IDC connector housing (J130/J107). The wires can sometimes be prized lose. I find that it if you push in the wires with a fine screwdriver, the connection between the wire and the connector pin are re established. Visually, you can sometimes see the wire in question raised to a higher level than the rest of the wires.

So if you follow my dribble - push in the wire "Pin8" on J130 and "Pin3" on J107. This will eliminate the common fault of an IDC connector issue.

Do you know how to use a multimeter ?

You could check continuity between the wires on the coil and J130 / J107
You could disconnect the coil and measure the resistance of the coil.

[felixthadog]

Matt -

The IDC connectors on the Driver board are notorious for developing faults over time. Moreso for high current applications like General Illumination, but on the occasion, even switch matrix IDC connectors can develop issues.

If you look on the two connectors you have highlighted, you will see the wires are "prized" into the IDC connector housing (J130/J107). The wires can sometimes be prized lose. I find that it if you push in the wires with a fine screwdriver, the connection between the wire and the connector pin are re established. Visually, you can sometimes see the wire in question raised to a higher level than the rest of the wires.

So if you follow my dribble - push in the wire "Pin8" on J130 and "Pin3" on J107. This will eliminate the common fault of an IDC connector issue.

Do you know how to use a multimeter ?

You could check continuity between the wires on the coil and J130 / J107
You could disconnect the coil and measure the resistance of the coil.

Thanks Nino, I will take a closer look at those IDC connectors tonight. As for a multimeter, I have one but I don't know how to use it  What do I need to set the multimeter to, what do I put the red and black points on, and what should I expect to see? 

Matthew

[Strangeways]

To check the coil - Set the MM to OHMS, and place the probe on each lug of the coil. You should see around 4 Ohms. Remove the connector to the coil (nearest the coil) - also check the wires are soldered on the coil.

[felixthadog]

To check the coil - Set the MM to OHMS, and place the probe on each lug of the coil. You should see around 4 Ohms. Remove the connector to the coil (nearest the coil) - also check the wires are soldered on the coil.

1) On my MM, Ohms has 5 settings (2000K, 200K, 20K, 2000, 200). Which setting do I use? 
2) Do I perform the first test with the machine switched on and the coil connected? 
3) After I remove the connector to the coil (nearest the coil), do I need to test using the MM again? If so, what value should I expect? Machine switched off or on? 

Matthew

[goodolddays]

Gday Matthew ..
Because you are looking for low ohms value (3 -4 ohms) .. set meter to 200 ohms. Machine should be switched off when taking readings.. and yes, test again after disconnecting the coil (if the value is higher than 3 - 4 ohms with coil connected)..

Also, with the coil disconnected, put the 9V battery across the coil lugs (no wires needed .. the distance between the battery terminals and the coils lugs is pretty much the same) .. this will fire the coil..  also. check that both the coil windings are still soldered to the lugs ..

To check the coil - Set the MM to OHMS, and place the probe on each lug of the coil. You should see around 4 Ohms. Remove the connector to the coil (nearest the coil) - also check the wires are soldered on the coil.

1) On my MM, Ohms has 5 settings (2000K, 200K, 20K, 2000, 200). Which setting do I use? 
2) Do I perform the first test with the machine switched on and the coil connected? 
3) After I remove the connector to the coil (nearest the coil), do I need to test using the MM again? If so, what value should I expect? Machine switched off or on? 

Matthew

[felixthadog]

Gday Matthew ..
Because you are looking for low ohms value (3 -4 ohms) .. set meter to 200 ohms. Machine should be switched off when taking readings.. and yes, test again after disconnecting the coil (if the value is higher than 3 - 4 ohms with coil connected)..

Also, with the coil disconnected, put the 9V battery across the coil lugs (no wires needed .. the distance between the battery terminals and the coils lugs is pretty much the same) .. this will fire the coil..  also. check that both the coil windings are still soldered to the lugs ..

To check the coil - Set the MM to OHMS, and place the probe on each lug of the coil. You should see around 4 Ohms. Remove the connector to the coil (nearest the coil) - also check the wires are soldered on the coil.

1) On my MM, Ohms has 5 settings (2000K, 200K, 20K, 2000, 200). Which setting do I use? 
2) Do I perform the first test with the machine switched on and the coil connected? 
3) After I remove the connector to the coil (nearest the coil), do I need to test using the MM again? If so, what value should I expect? Machine switched off or on? 

Matthew

Sorry for all the questions, but I have to make sure I am 100% certain in what I am doing.

- Does the machine need to be switched off at the mains before testing with the MM?

- When you say "with the coil disconnected", do you mean that the 2 connectors (male & female) near the coil should just be separated so that the coil is no longer connected to the driver board?

- You stated that I should be looking for low ohms (3-4 ohms) when the coil is connected, what does it mean if I get a higher or lower reading? If the reading is 3-4 ohms with the coil connected, do I still need to run the test with the coil disconnected? If so, what reading should I be looking for when the coil is disconnected?

Matthew

[goodolddays]

No probs with the questions Matthew .. we all started at the beginning at some time.
1. Turn machine off at the mains
2. Disconnect the coil from the driver board
3. Measure with the meter .. if the coil is good you should read around 3 - 4 ohms ..

 

Gday Matthew ..
Because you are looking for low ohms value (3 -4 ohms) .. set meter to 200 ohms. Machine should be switched off when taking readings.. and yes, test again after disconnecting the coil (if the value is higher than 3 - 4 ohms with coil connected)..

Also, with the coil disconnected, put the 9V battery across the coil lugs (no wires needed .. the distance between the battery terminals and the coils lugs is pretty much the same) .. this will fire the coil..  also. check that both the coil windings are still soldered to the lugs ..

To check the coil - Set the MM to OHMS, and place the probe on each lug of the coil. You should see around 4 Ohms. Remove the connector to the coil (nearest the coil) - also check the wires are soldered on the coil.

1) On my MM, Ohms has 5 settings (2000K, 200K, 20K, 2000, 200). Which setting do I use? 
2) Do I perform the first test with the machine switched on and the coil connected? 
3) After I remove the connector to the coil (nearest the coil), do I need to test using the MM again? If so, what value should I expect? Machine switched off or on? 

Matthew

Sorry for all the questions, but I have to make sure I am 100% certain in what I am doing.

- Does the machine need to be switched off at the mains before testing with the MM?

- When you say "with the coil disconnected", do you mean that the 2 connectors (male & female) near the coil should just be separated so that the coil is no longer connected to the driver board?

- You stated that I should be looking for low ohms (3-4 ohms) when the coil is connected, what does it mean if I get a higher or lower reading? If the reading is 3-4 ohms with the coil connected, do I still need to run the test with the coil disconnected? If so, what reading should I be looking for when the coil is disconnected?

Matthew

[ajlaird]

Mate, where do you live? I would be happy to come over for an hour or so after basketball (which finishes around 8:30pm). Sounds like you need some hands-on assistance. And do you have a soldering iron?

[Strangeways]

Do the coil test with the machine off and the coil disconnected 

I don't think there is a diode across that coil - If you get no reading, try swapping the red lead with the black lead at the coil.

If you get a reading of zero ohms, you have a shorted coil (unlikely) - if you get no reading, then the coil is "open" - more likely.