Road Show - Ted's Head Coil Replacement - Help Please

[simonlindsay]

Hi,

I have removed Ted's head, not for the first time but hopefully the last!

Basically, none of the eyes or lids are working on both Red and Ted. I did replace the SM 31-900 a few years ago in Ted's head (all eyes and lids worked except lids in Ted's) but when I switched the machine on, it started to smoke at the back of the machine in the Ted head vicinity. So I left it switched off for 7 years (too scared to switch it back on) and switched it back on a few months ago - everything worked on the machine except none of the eyes or lids on either head.

I removed Ted today and saw the lid coil was solid. I have not stripped the head completely as I wanted to clarify some points, so here goes...

I have attached photos to try and explain.

Firstly, is the coil in the right way? The plunger appears to be solid so I figure it has burnt out

Should the two wires (Brown/Red) go to the lug where the plunger is? And should the single Red/Black go to the bottom end of the coil? As per the pictures. Or is it the other way round?

I believe the coil is missing the centering flange ( I ordered one on the off chance it was missing) and assume it goes between the coil and the end plate.

The brass 'pawl' seems to be sticking out of the hole in the bottom - is this correct? I looked at the bottom of Red's head and it looks the same.

On the photo with the new coil, does the 'lip' go to the plunger or is it the flat bit on the end. Depending on this answer, will determine what to do with the wiring and which lugs the wires go to.

Once the replacement coil is in place and correctly wired, should I check transisitors or anything else?

Sorry for the long post and the many questions but I don't want the machine to smoke or burst into flames and not be able to play it for another 7 years!!

Thanks in advance.

Simon

 

[Mfresh]

I redid Ted's head a few years ago now. I will see if I can dig out the photos for you

 

[CHRIS B PINBALLS]

If the other coils have locked on and melted I would check all the transistors that control them as if you fit new coils and they are blown you will melt them again
Also make sure you are on the latest software as old software causes red or teds coils to lock on

 

[simonlindsay]

Hi Mfresh and Chris B,

Thanks for your replies. It would be great to see the photos as I'm not convinced that the coils are in the right way and that the wiring is potentially incorrect.

Good point about the transisitors - homepinballrepair.com explains how to check transistors so I'll do that as soon as I replace the coil. I think the others in Ted's head are ok. I am going to Check Red as well, just in case. I'll look into the latest software as it sounds like the coil issue might not go away otherwise.

Thanks again.

 

[pinballmania]

The coil can be connected either way round. It doesn’t matter. The centring flange goes furthest away from the eyes. The brass rod pokes through the centring flange.

If a coil has overheated to that degree replace its driving transistor.

 

[simonlindsay]

Hi,

Thanks to Pinball Mania for the advice and supplying the centering flange a short time ago. I'll be ordering another centering flange off you for Red - I notice you have two in stock plus some other bits.

I have attached a photo of the Q54 transistor (I assume it is the driving transistor) and it looks like some work has been done on it previously. I tested the transistor and got the right readings (red lead on left leg) except for the black lead to left leg and red lead to right leg which showed about 1.65v. On the repair forum it suggests the reading should be about 1.9v - will it make much difference? I tested them in circuit.

I have attached two other photos of previous 'work'. One shows the J120 G.I. molex or should I say molexes! The other shows the BR3 which had melted onto the fins. I'm surprised my machine works as good as it does!

From a previous post, I am running the U6 L6 software which, I believe is the latest?

Thanks again for the advice - I really appreciate the help!

Simon

 

[simonlindsay]

Oops, forgot the photos.....