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Help - LOTR problem with "Destroy the Ring"

AlanJ

Site Supporter
Joined
Dec 27, 2017
Messages
7,725
Location
Leeds, West Yorkshire
Alias
Alan
I have reached the "Destroy the Ring" feature several time now on my LOTR and each time I just cannot get it to complete the "destroy" - After completing all the orbit shots, you are invited to shoot the ring and it flashes, I shoot it and it holds the ball as intended in the ring via the electromagnet. A second ball is issued and I'm once again invited to shoot the ring - it's flashing to indicate such. Shooting the ring once or even several times - either the ball bouncing out, or going right through and displacing the first ball has no effect whatsoever, and it still indicates to destroy the ring.

I tried changing the menu setting to 1 ball - this is where it doesn't hold the ball, and so you are expected to shoot the ring with the first ball, which is returned to the playfield after shooting the ring the first time, instead of being held. Again, I tried several shots to the ring and nothing happens??????

Today I simulated all this again with the glass off and again I can't destroy the ring.

I checked the opto sensors around the ring and they work as they count other hits to the ring in other parts of the game sequence, so at a total loss. I also checked the micro swtch at the bottom of the ramp which is triggered by the spinner - this is working fine too.

Anyone got any ideas please?
 
Thanks @chris b - @Spadge also sent me something that also suggested that, so I had a look at it and yes it looks like that trough switch needed adjusting. I went into the LOTR menu under diagnostics and their is a ring test option to check the 3 switches associated with it.

Whilst messing around today I managed to somehow blow the fuse for the ring electromagnet, and replacing it has given me a strange situation now: When I power on the machine, the rings Electromagnet is activated immediately and it stays on - Soon get a warm toasy burning coil smell too. Looks like I've knackered something else up now, perhaps the MOSFET for the ring has blown. Would that cause such a symptom?
 
The original problem is now fixed, the back micro switch being the culprit - it is now possible to destroy the ring. Replacement MOSFET ordered to fix the electromagnet issue.
 
Ok so this morning I fitted the replacement Mosfet to the I/O board. Powered on and ran the ring magnet test - nothing at all. The ring magnet is not functioning at all now. I have been into the diagnostics and ran the coil tests - can't get anything out of the ring magnet. So.....Is my new MOSFET faulty, or is there a problem further up the line on the I/O board - I can see the Mosfet is driven by a chip - HCT273 - which apparently is a Flip Flop chip. I presume I need to now do some tests and try identify where this is going wrong? Do I need to get a logic probe for this?
 
Problem with 'Destroying the Ring'?

Only a pinhead would understand that headline post!
 
Ok so did some more tests, I have two problems.

1. The Mosfet is not switching on - either a Mosfet problem or the driver IC flip flop circuit that drives it is blown. I can't tell until I get a new Mosfet and a Logic Probe.
2. The Ring Magnet circuit is drawing too much current. I bypassed the Mosfet with a trailing wire and the ring magnet switched on when I bypassed. However the 5A fuse lit up red, suggesting that a lot more current than should be is going through the circuit. I suspect the ring magnet itself as the culprit - If I think back to the time when everything was working.... I had it running for an extended time trying to "destroy the ring" in a game, and it was holding on tight to the first ball. After a while there was a burning smell (yep that familiar warm coil smell) and then the fuse blew.

I think that the ring magnet has shorted, drawn too much current, blown the original Mosfet into a short and then finally blown the fuse. I replaced the fuse and it blew again, so I replaced the Mosfet and it either blew again but this time open circuit, or I blew it with static as I fitted it.
.
Anyhow - looks like the next job is to remove the ring magnet and test it. It looks like this coil has a very low resistance anyway 2.9 Ohms. So will be drawing a high current as it is. Any sort of short or partial fusing of the windings will have caused a big current drain.

I'm scratching my head here - If these coils have such a low resistance - e.g. 3 ohms, and are being powered by 50V, then wont they draw about 17A current???? 50/3 ~= 17A ??
 
I'm really scratching my head now - I can't see how the circuit can work without a huge current drain, unless the circuit is pulsing the coil very quickly?
 
Hmm,

I think I#m barking up the wrong tree. I have disconnected the I/O PCB jumpers - so I have isolated the ring magnet circuit from the board. The whole circuit is testing out at around 4 ohms, whihc looks ok - the wiring diagram in the manual shows that there in only the ring magnet and it's associated diode in the circuit that I am testing, so I conclude that the coil is ok after all.

So,,,that leaves me with the replaced Mosfet. I'm deeply suspicious of this.

There is a Mosfet test point on the I/O board, so I connected everything back up and used that to test the various Mosfet's Nos 1 - 16 - they all worked apart from the one I've replaced, so it looks like I've proved this is the problem. I had earthed the board and myself whilst doing the soldering this morning. Hmm. Ok, order a new one and try again. I seem to remember from my youth that we used to deliberately short the 3 prongs with thin wire connected to earth as we fitted them into circuits..........
 
Sounds like a new ring magnet is required along with a new MOSFET and fuse... Unlikely to have caused further damage.
 
going from bad to worse. after deciding to call it a day and put it all back together. i then find the left flipper no longer working. fuse blown on underside of playfield. i replaced this and powered on. immediately the left flipper activates. stays on for a second or so then the fuse blows. it looks like another mosfet has blown. can’t understand why though. seems that this old bird is a bit sensitive


Sent from my iPhone using Tapatalk
 
Sounds like a new ring magnet is required along with a new MOSFET and fuse... Unlikely to have caused further damage.
Thank you for the advice, I will proceed as suggested. Just awaiting new delivery of MOSFET's. Pinside forum people suggested replacing with IRL540 type MOSFETS which are apparently more rugged.
 
Thank you for the advice, I will proceed as suggested. Just awaiting new delivery of MOSFET's. Pinside forum people suggested replacing with IRL540 type MOSFETS which are apparently more rugged.


that's what i use
 
The damn mosfets didnt arrive in todays post, so looks like I'm stuck until next week. Monday and Tuesday are busy days for me, so looks like LOTR out of action for a few more days.

I've been doing some more research and I wonder if I should also replace the diode on the Left flipper coil. May as well, it's a cheap part and a lot easier to access and replace compared to a MOSFET on the main I/O board.

I'm also wondering if I should solder some sort of screw terminal block onto the I/O board where the MOSFET is supposed to go, so I can screw a new mosfet in & can easily swap these out in future? Something like this
Untitled.png
 
I'm also wondering if I should solder some sort of screw terminal block onto the I/O board where the MOSFET is supposed to go, so I can screw a new mosfet in & can easily swap these out in future? Something like this
View attachment 59308

I wouldn't recommend going down this route as it will make the game harder to sell on in the future.

Regarding fixing - I think you've had a go and it's probably time to get someone like Jim in to sort it....
 
I wouldn't recommend going down this route as it will make the game harder to sell on in the future.
Regarding fixing - I think you've had a go and it's probably time to get someone like Jim in to sort it....
Yes Jim is only a couple of miles away.....
No brainer... :thumbs:
If you are not confident just wait till Jim is back from holiday

I'm back :)

Just reading through this thread!, I'm happy to pop over and have a look or if you want to drop the driver board off with me then i'll have a look and see if i can sort it out.

Regarding this

I'm scratching my head here - If these coils have such a low resistance - e.g. 3 ohms, and are being powered by 50V, then wont they draw about 17A current???? 50/3 ~= 17A ??

The answer is PWM control, (pulse width modulation) Stern (Sega/DE) Use this process a lot. Have a look at the flipper coils to. They are only a single winding, so they use a pulse width signal to turn the coil on and off repeatedly very fast. By changing the off and off times (in ms) you can control how powerful the coil is and allow it to be on for long periods of time. For example the stern flipper hold cycle is something like on for 2ms, off for 18ms

However, it is not a perfect design and (as has been well documented) if you leave these coils activated even with pwm control they will blow fuses eventually. Sterns control timings are not perfect!! (They do not allow for warming up of the coils over a period of time and hence increased resistance)
 
Thanks Jim @myPinballs for the offer of help and also for the explanation above of how the PWM system works for the coils, very interesting. I've got some parts coming tomorrow, so I'll try those and if It still doesn't work then I'll call in the cavalry!
 
Parts arrived yesterday morning, frustrated as I was out all day and all night, and really keen to get on with this. Today I had to take my Mum to the hospital for a consultation. So delayed again. I must admit by the time I got home early afternoon my enthusiasm for taking the board out etc. has waned.

A cup of Yorkshire tea and a fish finger sandwich and I'm revitalised!

So,
1. I/O board out, carefully unplugging the 14 wiring connectors, and ensuring I'm not statically charged. Board onto a makeshift Static mat (silver foil - earthed).
2. Desolder two of the MOSFET transistors and check and clean the board. I notice one of the track spots has lifted away, but it's only to hold the leg of the transistor on the underside of the board, and doesn't connect anywhere - the topside of the board does and is intact. Also note one of the other tracks has partially burnt away but there is enough there to solder the new leg onto. (This is the transistor that controls the ring magnet - looks like it got very hot at one time.
3. Test the removed Mosfets. The one for the left flipper has continuity between Gate and Source - so looks duff. The ring magnet one has no continuity across any of the legs, but I suspect this is blown and will never switch on.
4. Carefully solder in the 2 new parts, trim the pins and check that electrical connection is made to the PCB trace wires on the lower and upper sides of the board. I made sure I and the board and parts were electrically grounded and even unplugged my soldering iron to solder on the pins. Pretty sure I have done a good job of keeping these safe. I could have wound some thin wire temporarily around the three legs, but I felt I'd done enough.
5. Double check the new parts, soldering, connectivity and for shorts. Clean off excess flux on the board between the joints and tracks.
6. Check the rest of the board and components, all looks ok.
7. Check the fuses in the board, some are the wrong rating, so replace correctly as per the manual. Some are blown - Ring Magnet originally specified as 3A, but later advisory is 4A, so fit that.
8. Replace board and fit and check all 14 wiring connectors
9. Double check
10. Triple check
11. Put back box back together for a moment as I realsie I've not replaced the diode on the left flipper coil.
12. Remove glass and raise the PF - a bit trickier than usual as this pin has Pinstadium lights which need to be removed and placed into the pf, and care needed to lift the pf out past the strip magnets on the sides of the cab - there are also mirror blades fitted, so this is a very tight squeeze.
13. Cut off the diode - I wanted to test it just out of interest, but managed to drop it in the machine. Took me 20 minutes to find it! Tested it - looks fine - but I'm not unhappy - I needed to test it to do a thorough job and I now know that the culprit is more likely the transistor I've just replaced. I also now know for future ref that diodes are less likely to fail than transistors.
14. Solder on a new diode, double checking I've got the polarity right.
15. Replace 3A fuse on underside of pf near the flipper - it was blown of course.
16. Put the pf back together and re-setup the pinstadium lights.
17. Remove backglass and DMD/speaker board so I can see the I/o board completely and can see all the fuses, especially the ones that power the ring magnet and the 50v coils general.
18. Dare not switch it on ----- I need another cup of tea to build up some courage and maybe I just need to check everything one more time.........
19. Switch on at mains plug - no bang
20 Switch on using the main on/off switch under the cab.
21. BOOM!!!!!
22. Only joking - seems to be powering up all ok........no left flipper on immediately, no fuses glowing or blowing..........
23. Games boots ok - but no playfield lights????
24. Switch off quickly
25. Go check all those 14 board connectors again and then the fuses in the board. I noticed earlier that some fuses have been pushed in too far and too hard by someone previously and the fuse holders have become deformed. I pull out the fuse for the 18v lights and reseat. Also check the 2 connectors that drive the lamp matrix, these now connect vi an OCD driver board so check the wiring to that. All looks good.
26. Power On #2 - all ok, with lights this time. Suspect it was the fuse not seated properly.
27. Test left flipper - all ok
28. Play a game to test the ring magnet. Takes me two lost balls before I hit a clean shot to the ring and YES! The ball is held by the ring magnet, and then released as intended after the mode sequence intro plays out.
29. Re-assemble the backbox and the pf glass. Re-test once more. 100% fixed.

Job done.

Things I have learnt today:

1. Take your time and only start a job like this once you are in the right frame of mind and have relaxed.
2. Plan out what you are going to do and how you are going to do it.
3. Get all your tools out ready to go. Spares out too.
4. Work slowly and with care
5. cut off old components first - it makes de-soldering a lot easier.
6. Use a solder sucker too.
7. Earth up if handling static sensitive devices
8. Check, check and double check.

Things I have learnt from this overall experience:
1. Manual is your friend - make sure you get a manual with each pin you buy. If one is not included, ensure you can download one or purchase one elsewhere.
2. Fuses - don't use the wrong fuses - Buy in a good stock of the common types. (I'm also investing in 3A and 5A circuit breakers - courtesy of @myPinballs )
3. Don't go testing out bits of your Machine that already work using the test points on a board just for the hell of it. I am sure this is what blew my left flipper transistor. Instead just use test points to check that a non working part is indeed non working.
4. Diodes - like fuses - cheap parts - get in a stock of these so you can easily replace ones on coils that are not working properly.
5. Think about what is or isn't happening in the game, this logically points you to the probable cause.
6. Don't be afraid to tackle a board repair. Especially power Transistors, these are quite likely to be fail points. When replacing a part, do some research to find out if the exact part number is the best or whether there is a better alternative part that others have used instead. In my case I bought the original replacement part £5.99 as it is obsolete and hard to find. I then discovered that the replacement part is not only better and more robust, but also far cheaper £1.40.
7. Do not despair! Most things are fixable and if you can't fix it, there are people you know who can.

Thanks to everyone above for advice and support - really helped me successfully sort this out. THANK YOU!
 
Doing a job like that you need the correct tools to start with a good solder station also that board is a pain to work on the transistor are tightly packed in and hooked in on the back and tight
You are best of buying a cheep knackered board and practicing removing comments of that before tackling the real thing I see more and more people having a go and doing more damage than good don’t be tight and give it to someone who knows what they are doing will be cheeper in the end
 
Thanks @chris b - One thing that put me off a variable temperature solder station was the fact that they could probably put out more static than a normal soldering iron - but I guess if you buy a decent one it won't, whereas a cheaper one might.

I'm just glad it wasn't SMD board, otherwise it's a hot air gun rework station on the purchase list.
 
Parts arrived yesterday morning, frustrated as I was out all day and all night, and really keen to get on with this. Today I had to take my Mum to the hospital for a consultation. So delayed again. I must admit by the time I got home early afternoon my enthusiasm for taking the board out etc. has waned.

A cup of Yorkshire tea and a fish finger sandwich and I'm revitalised!

So,
1. I/O board out, carefully unplugging the 14 wiring connectors, and ensuring I'm not statically charged. Board onto a makeshift Static mat (silver foil - earthed).
2. Desolder two of the MOSFET transistors and check and clean the board. I notice one of the track spots has lifted away, but it's only to hold the leg of the transistor on the underside of the board, and doesn't connect anywhere - the topside of the board does and is intact. Also note one of the other tracks has partially burnt away but there is enough there to solder the new leg onto. (This is the transistor that controls the ring magnet - looks like it got very hot at one time.
3. Test the removed Mosfets. The one for the left flipper has continuity between Gate and Source - so looks duff. The ring magnet one has no continuity across any of the legs, but I suspect this is blown and will never switch on.
4. Carefully solder in the 2 new parts, trim the pins and check that electrical connection is made to the PCB trace wires on the lower and upper sides of the board. I made sure I and the board and parts were electrically grounded and even unplugged my soldering iron to solder on the pins. Pretty sure I have done a good job of keeping these safe. I could have wound some thin wire temporarily around the three legs, but I felt I'd done enough.
5. Double check the new parts, soldering, connectivity and for shorts. Clean off excess flux on the board between the joints and tracks.
6. Check the rest of the board and components, all looks ok.
7. Check the fuses in the board, some are the wrong rating, so replace correctly as per the manual. Some are blown - Ring Magnet originally specified as 3A, but later advisory is 4A, so fit that.
8. Replace board and fit and check all 14 wiring connectors
9. Double check
10. Triple check
11. Put back box back together for a moment as I realsie I've not replaced the diode on the left flipper coil.
12. Remove glass and raise the PF - a bit trickier than usual as this pin has Pinstadium lights which need to be removed and placed into the pf, and care needed to lift the pf out past the strip magnets on the sides of the cab - there are also mirror blades fitted, so this is a very tight squeeze.
13. Cut off the diode - I wanted to test it just out of interest, but managed to drop it in the machine. Took me 20 minutes to find it! Tested it - looks fine - but I'm not unhappy - I needed to test it to do a thorough job and I now know that the culprit is more likely the transistor I've just replaced. I also now know for future ref that diodes are less likely to fail than transistors.
14. Solder on a new diode, double checking I've got the polarity right.
15. Replace 3A fuse on underside of pf near the flipper - it was blown of course.
16. Put the pf back together and re-setup the pinstadium lights.
17. Remove backglass and DMD/speaker board so I can see the I/o board completely and can see all the fuses, especially the ones that power the ring magnet and the 50v coils general.
18. Dare not switch it on ----- I need another cup of tea to build up some courage and maybe I just need to check everything one more time.........
19. Switch on at mains plug - no bang
20 Switch on using the main on/off switch under the cab.
21. BOOM!!!!!
22. Only joking - seems to be powering up all ok........no left flipper on immediately, no fuses glowing or blowing..........
23. Games boots ok - but no playfield lights????
24. Switch off quickly
25. Go check all those 14 board connectors again and then the fuses in the board. I noticed earlier that some fuses have been pushed in too far and too hard by someone previously and the fuse holders have become deformed. I pull out the fuse for the 18v lights and reseat. Also check the 2 connectors that drive the lamp matrix, these now connect vi an OCD driver board so check the wiring to that. All looks good.
26. Power On #2 - all ok, with lights this time. Suspect it was the fuse not seated properly.
27. Test left flipper - all ok
28. Play a game to test the ring magnet. Takes me two lost balls before I hit a clean shot to the ring and YES! The ball is held by the ring magnet, and then released as intended after the mode sequence intro plays out.
29. Re-assemble the backbox and the pf glass. Re-test once more. 100% fixed.

Job done.

Things I have learnt today:

1. Take your time and only start a job like this once you are in the right frame of mind and have relaxed.
2. Plan out what you are going to do and how you are going to do it.
3. Get all your tools out ready to go. Spares out too.
4. Work slowly and with care
5. cut off old components first - it makes de-soldering a lot easier.
6. Use a solder sucker too.
7. Earth up if handling static sensitive devices
8. Check, check and double check.

Things I have learnt from this overall experience:
1. Manual is your friend - make sure you get a manual with each pin you buy. If one is not included, ensure you can download one or purchase one elsewhere.
2. Fuses - don't use the wrong fuses - Buy in a good stock of the common types. (I'm also investing in 3A and 5A circuit breakers - courtesy of @myPinballs )
3. Don't go testing out bits of your Machine that already work using the test points on a board just for the hell of it. I am sure this is what blew my left flipper transistor. Instead just use test points to check that a non working part is indeed non working.
4. Diodes - like fuses - cheap parts - get in a stock of these so you can easily replace ones on coils that are not working properly.
5. Think about what is or isn't happening in the game, this logically points you to the probable cause.
6. Don't be afraid to tackle a board repair. Especially power Transistors, these are quite likely to be fail points. When replacing a part, do some research to find out if the exact part number is the best or whether there is a better alternative part that others have used instead. In my case I bought the original replacement part £5.99 as it is obsolete and hard to find. I then discovered that the replacement part is not only better and more robust, but also far cheaper £1.40.
7. Do not despair! Most things are fixable and if you can't fix it, there are people you know who can.

Thanks to everyone above for advice and support - really helped me successfully sort this out. THANK YOU!



Tho the op has left out most important lesson, a fish funger butty and a cuppa is needed
 
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