U bolt on my K4600 flyback broken

[lilypad19]

I'm recapping and cleaning my K4600.
A part of the Ubolt in the flyback transformer was broken inside of the casing.

My *guess* is that it isn't a big deal - but I wanted to check with you guys to see if it is or not..

It all seems relatively solid still
Thx for any feedback

 

[PassivePac-Man]

The picture isn't showing up.

Just worked on a 4600 today. Are you talking about the part of the plastic that holds it to the frame?

 

[lilypad19]

Weird - I can see the picture and I just rechecked the link..

There is a thin (1/8" or so) U-bold that goes appears to hold a core in the center of the transformer with bolts that end on a metal plate..

The U-Bolt itself is broken.

 

[security0001]

the bolt that holds the ferrite core if its broken than it needs to be fixed otherwise if either half of the ferrite comes out you will lose the air gap spacers and that will be bad. i would try to find a way to secure it properly.

 

[lilypad19]

Thanks I am a little worried about that. I'll figure something out.. I bet I can get a tap that small and just make a replacement.

 

[lilypad19]

It turned out to be a bit easier to repair than I thought.
First was a trip to the hardware store - I determined the original threading was metric (3mm). I also checked the original and it was non-magnetic and hard to cut. That tells me it was stainless steel.

I picked up 3/32" stainless rod, a 4-40 thread tap and a couple of small nuts and washers. Next I bent the wire with a tool I had for crimping ducts and a couple of needle nose pliers.

Once I got it to shape I clamped it in the vice and tapped the 4-40 threads onto my replacement. Little 4-40 die cost $5

Fits perfect and is nice and snug.

 

[blown23t]

Very nice work.. you obvious have a few metal skills.. nice job!!

 

[security0001]

beautiful job!!!

 

[lilypad19]

Thanks guys!

 

[mecha]

ok now that was awesome.

we should start a 4600 fan club, since I know so many people that hate/can't understand them.

 

[lilypad19]

Thanks again - I updated the pictures to show the the die for cutting threads - $5. (meant to put it in the first time around) I turned it using a socket wrench and thread cutting oil.

 

[security0001]

when are you starting production on them????

BTW: the K4900 would be the next one...

 

[Atari The Jedi]

I for one will vote for a 4600 fan club and would like one of these for mine [emoji16][emoji16][emoji16]

 

[smeatr0n]

This is amazing work, 2/3 of my 4600's have broken u bolts at exactly the same spot just like this. If you ever make a couple more of these things I'll take three!

 

[ArcadeTechGW]

They aren't hard to make. Make one yourself.

He just about showed you the entire process.

The only thing I would suggest is putting a little oil on the die as you start cutting. While this isn't a high speed process, the oil will keep the die sharper in the long run.

That part is machine bent / formed. The rounded edges are to prevent stress risers which can cause cracking and also keep it from applying pressure to the plastic corners which are more susceptible to fatigue over time. Note how it applies pressure to the top of the flyback.

 

[smeatr0n]

They aren't hard to make. Make one yourself.

He just about showed you the entire process.

The only thing I would suggest is putting a little oil on the die as you start cutting. While this isn't a high speed process, the oil will keep the die sharper in the long run.

That part is machine bent / formed. The rounded edges are to prevent stress risers which can cause cracking and also keep it from applying pressure to the plastic corners which are more susceptible to fatigue over time. Note how it applies pressure to the top of the flyback.

Do you suppose there could be negative side effects down the road to my less attractive solution?

 

[ArcadeTechGW]

Do you suppose there could be negative side effects down the road to my less attractive solution?

No. Tie wraps can't make a 90 degree turn. You'll probably have to replace them - they will age crack and fail.

 

[smeatr0n]

No. Tie wraps can't make a 90 degree turn. You'll probably have to replace them - they will age crack and fail.

Thanks you're likely right. To be fair though, the stainless steel rod even failed over time. I wonder how long it's been working unsupported like this?

 

[ArcadeTechGW]

Thanks you're likely right. To be fair though, the stainless steel rod even failed over time. I wonder how long it's been working unsupported like this?

I can't disagree with your logic.

I do understand tie wraps and stainless steel - I'm an engineer.

That the stainless steel failed mid-span (not at a bend) like that indicates some sort of long-range low cycle fatigue was in play. That, or an overstress condition from someone tightening it up again and again and again.

Stainless steel is fairly tolerant of some abuse, mostly in water systems where the chromium (which gives stainless steel it's anti-rust properties) can absorb some stress that would normally cause pitting damage.

However, everything has a tensile limit, so I suspect that this is low cycle fatigue probably with millions of micro-pulses from the flyback.

Your tie wraps will suffer from the heat (the flyback definitely gets warm) and temperature cycles. I'd expect a failure in 3 to 5 years for commercial grade tie wraps, slightly longer for nylon specialty tie wraps.

Your results may vary by how often you operate the game and for how long.

Having said that, I've seen thousands of tie wraps broken in my life from normal every day stresses.

 

[smeatr0n]

I can't disagree with your logic.

I do understand tie wraps and stainless steel - I'm an engineer.

That the stainless steel failed mid-span (not at a bend) like that indicates some sort of long-range low cycle fatigue was in play. That, or an overstress condition from someone tightening it up again and again and again.

Stainless steel is fairly tolerant of some abuse, mostly in water systems where the chromium (which gives stainless steel it's anti-rust properties) can absorb some stress that would normally cause pitting damage.

However, everything has a tensile limit, so I suspect that this is low cycle fatigue probably with millions of micro-pulses from the flyback.

Your tie wraps will suffer from the heat (the flyback definitely gets warm) and temperature cycles. I'd expect a failure in 3 to 5 years for commercial grade tie wraps, slightly longer for nylon specialty tie wraps.

Your results may vary by how often you operate the game and for how long.

Having said that, I've seen thousands of tie wraps broken in my life from normal every day stresses.

Brilliant, that's great. These are in fact nylon straps rated for 85°c. My games are only on for a couple hours a week, I'll inspect this one in three years and see how she's held up. Maybe I will have bought some better tools by then. Cheers