At a minimum repin J3 & J4 on the SDB, and J4 on the MPU. Note that I repin every connector as a personal preference.

J3 & J4 on the SDB since they carry the signals to the board, J4 on the MPU since those pins usually get eaten up when the battery leaks on the original MPU.

A bonus for the after market displays is that they do not use the high voltage section of the SDB. If your hi voltage section is fused, just remove the fuse.

Page 26 of the manual shows the MPU and the test points

https://www.ipdb.org/files/1755/Bally_1979_Paragon_English_Manual_color_with_paginated_schematics.pdf

The rectifier board may not be plug and play - depending on what you got, there's soldering involved and you have to crunch down on the wires when reinstalling the rectifier board on the ground plane. Since its playing, I would recommend you wait for your maintenance guy to come by and look it, make an evaluation as to whether it needs replaced.

The NVRAM is easy, changing the SDB is easy. Use the end of a cheap Bic pen housing to pinch the plastic standoffs to get the board off. (Remove the ink stick)
Learning to solder and use a voltmeter will take some time. Practice on a junk circuit board. I recommend going to a thrift store and buy a cheap clock radio, take it apart to get to the circuit board, and practice on it. Above all, have fun, and make room for another machine - they tend to multiply.

You can start the machine but it’s not easy. You turn it on, it pops up in audit mode, then turn it off and on quickly. It may take several tries.

The game will turn on in factory default settings, so you will have to coin up to play.

I don’t think you will have any problems installing the nvram.

The Bally ram is socketed. Williams were not.

Remember that the white wire goes to the silver screw, black wire to the gold screw, green wire to the green screw.

If the cord wires are not color coded, see if the existing plug is polarized. The widest blade is the white (common) wire, the smaller blade is the hot(black) wire, and the wire to the missing piece is ground.

Remember that the hot wire is the one that is switched.

That plastic piece is held in place by the roll pin. Get a new piece, remove the roll pin, install the plastic piece and push the roll pin back in.

I am not near a catalog, so I can’t help with a part number. PBR or Marco probably has them.

Post caps. Pinball Resource has them in white and black.

My personal preference is white, but you do you.

Look at the flyer and see what they had if you want to keep it original looking.

Make sure switches 6 and 7 are not in the off position.

On your mpu( where you installed the ram) are 32 switches. Switches 6 & 7 are off, which tells the MPU not to award credits for high scores. - it may be keeping the board from keeping the high score

Yes. That’s the beauty, along with no more batteries.

The lamp board does not drive the gi lights in the back box. Look for a bad connection on your 7.5 VAC connection.

I don’t have a schematic with me, so going by memory, (I’m old, so verify!) the AC comes from the rectifier board to the back box. The wire should connect to the braid feeding the lights on the backboard. Those wires at the source have the connections you want to check. Personally, I would look close at the rectifier board and where the wires connect to the braid.

Squeeze one end of the pin and try again. The head will eventually fly off with use.

If you crimped those pins, don’t do any more until you review how to properly crimp.

There are two sets of tines. (probably not the right word). The set closest to the barrel crimps into the bare wire. The set where the wire goes into the pin should crimp onto the plastic covering of the wire.

You should not be able to see the wire strands when looking at the connector. At best, it’s a weak crimp, at worst, a strand can break and migrate toward the wire next door. (Murthy’s Law)

Paragon - the red wire you crimped will work, however, the strands are too long. They should not be on top of the little clip that locks the pin into place on the connector. That clip has to be pushed down in order to get past the locking lip in the connector. If that clip does not have enough room to be pushed under that lip, you may never get that pin out again without damaging the connector body. Once that lip in the connector body is damaged, it may not hold a pin in place when putting the connector onto a circuit board.

This is why I always look at the back of each connector after plugging it in, especially if I don't know the history. If the lock mechanism is bad, you will see the back of the pin raised above the connector body. You can push it back into the connector and hope the friction fit keeps the pin in place.

Good effort - you're getting better.

Go ahead and change Q59. They don’t cost much, and yes, any and all components can fail and not give a visual indication.

If only it were that easy to tell when a component is bad….

Yeah - that one failed hard just to help you out.

They don’t all fail that way.

Just pulling your leg on the “help you out”.

Agreed.

Good thing to get that cord cap replaced. Did you replace the entire cord, or just the cap? Did you verify the hot wire is on the correct blade? It looks like that is a non polarized cap. Just asking for your own safety.

Here in the US where I run around with electricians, we always called them "Cord Caps" because that was the cap on the end of a three conductor wire. I've heard of "Mains plug" or "Plug" and a few other variations. Sometimes is fun to see what things are called in different parts of the world.

On the plus side, I think we both knew what we were referring to. Gotta have fun in life

Out of the 153 million results, there was a subsection labeled electrical.

I wonder if the models in the pictures are comfortable with being called cords

There's a good thread that talks about pinballs, sizes, grades, sources, etc. It's worth the read. Here's the thread name - I'm not sure how to directly link it.

Pinball Balls
By Cbsanborn8488