Thought this may be a good place to ask this:
Does anybody have any experience in replacing the power supply on one of the small chinese neon signs?

I got an equivalent replacement (3KV 30mA). It is just the supply with in and out leads (no line cord/switch). I was going to splice onto old power cord for input. Output to neon is long enough to reach tubes, so was going to pull end caps and twist like original, but....

When I pulled end cap off tube, there was a diode and small disc capacitor in there. Also, the old supply has a component of some type in-line (covered in shrink tube) on both output wires. Additional Diode? Fuse of some type?

Can anybody tell me what the purpose of these compenents is? Do I need to leave them all in circuit and cut/splice new supply in closer to supply?

Any experience with this is greatly appreciated. Thanks!

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Here is a pic of what was under the boot on one end....hoping it will spark someones thoughts as to why it is there and if it is needed....

Thanks

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Thanks. I agree that it seems a bit small. It is only a 1N4001! I believe max rating is 1KV on those and that NST is at least 3KV.

I'm not sure what is under the shrink tube on both lines...I think I'll go back and peel off tubing to see right now. I assumed another diode or inline fuse, but I am beginning to wonder if it is just a splice...

I purchased this sign used knowing it was a bit flaky...I wonder if someone already tried modifying it in weird ways...

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Ok...sooo...I ripped of shrink tube...it is now obvious that this light has been hacked. The black wire at the splice is different at either end...no component under shrink like I really thought I was going to find.

I think someone simply hacked stuff.
I'm a little iffy still, but I think I am going to remove transformer, take out under rated diode/cap, and just wire in new transformer (switching supply style) direct.

I spent hours online and have emailed a number of places. I could not find ny reference to diodes on a neon sign and the couple places that were kind enough to respond did not know either.

Idk if Ill get it done tonite, but I will post the results (good/bad/blown up, lol) when I'm done.

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Wow! The 4007 is the 1kv I was thinking of. Spec sheet I just pulled lists the 4001 at only 50v!

I wondered about the voltage. It had what I believe was a 3kv and that is what I got to replace it....it is a smaller size sign, but does have the thin tube (which I read can require higher voltage?), so you may be right. I Honestly don't know at this point.

Maybe I will bech test it with the 3kv just to see if it even tries to light (dead right now).

Suprisingly, the 1N4001 seems to meter just fine...weird.

Got new transformer wired in. Lit up easy. Has a couple darker spots (center section of "M" in pacman specifically), but seems to light up ok now!

It is only a 3KV transformer....idk if it has dim spots because of that, or if it is just plain worn/old neon (which may be what took out old transformer in first place).

It is good enough for me for now as I dont care to spend any more time and money on additional work, but....

I am curious, what does happen if you use too low a transformer? Does it flicker/not light?

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Wow! Just found that depending on what section I touch, other areas flicker....even an entire ghost will go out whil I touch a different one! Guessing it is because transformer toi small????

While I do not know standard tube sizes....and I am sure it is really a metric measurement...

As a best estimate, it is approximately 1/4" O.D. tubing and about 10 feet if it.

Ohh dang! Thanks Kingbw!!!

SOOOOO NOT the transformer someone had on mine!

Sadly, it looks like the specs on yours are the same as the one I replaced it with.

Very confused

Idk if I should try a higher voltage? Or maybe split ghosts from pacman and add in a second 3kv (bought 4, so already have some) ....
Or if it is just plain worn

Thank all you guys for all the input!

I rewired the 3kv to just the ghosts and they run much better....still a little spotty looking (can slightly see little "dots" of neon) on first ghost.

If it ran perfect, I would say, just add separate 3kv tramsformer on lettering....but. I wonder of 3kv on each section is even enough?

Or maybe I really need like 9 or 12kv for whole thing :/

This weekend, I was thinking of separating the ghosts from the pacman words and trying something like that with 2 transformers. I may also go back and try cleaning off the leads coming out of tube as the copper seemed a little dark like a little oxidation (or maybe from heat). Thinking a lite fiberglass brush or something gently.

Thanks for the extra input.

Took an extra week before I got back around to working in sign. I got a fiberglass bristle brush and cleaned the copper wires off tubes. Hard to capture in pics, but shined up nicely....didnt make much difference in performance. Before and after cleaning.

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Sooo....replacing with single new 3KV 30mA supply lit whole unit but dim in some spots and touching tube with finger would cause a ghost to turn off. Also, "M" in pacman was dim. Hooking same new supply to only ghost half lit them better and no longer would a ghost go out, but first ghost is kind of bubbly inside (I don't know the term, but I am sure you know what I mean-like you can see it flowing/dancing a bit). Cleaning wire leads didnt do anything noticeable.

I left new supply on only the ghosts and added a second 3KV 30mA supply to run "pacman".

Final result...same little chase looking effect in first ghost, and same dim middle of "M" in pacman. Been on 20 min and no change.

However, didn't get worse and still looks pretty good; so, while not quite perfect, compaired to dead....I'll call it a win!

It's honestly probably a little old/worn/outgassed...like I said, I got it used and have no idea it's age or useage hours.

Thanks again for the help guys!
Time to put some shades on and stare at the beautiful glow!

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Thanks. I figured both the one ghost and the "M" were just wear at this point toi. No ground wire. I cleaned and twisted tight only the ends with leads I was working on, but did NOT check any of the ones going from tube to tube. And you are right, one of the leads I worked on did have a lot of black paint crap all over it; got off what I could and made sure wire was on good bare spot as best I could.

I will clean and check the other's as well now.

Thanks!

Thank you very much for the extra info Retropin! I had already bought a few of those cheap chinese supplies, but I will certainly be checking out some better ones now.

Thanks for the voltage explations too

'what kind of kid smells like Armour hotdogs...'

Isn't that how it went?

Love that Landshark sign!

For all you fellow neon lovers.

https://www.neonmuseum.org/

And Tim Burton fans!!!

https://www.ktnv.com/news/coronavirus/neon-museum-offering-facebook-live-tour-of-tim-burton-exhibit?fbclid=IwAR1KOYiSkhLqIMDoOWnUa9PReRQI0KbUFsyb0G5fcr3U4cVTG1_SmiV6XWM

I've never used Facebook live stream stuff...Hopefully I can figure it out. If not, hoping the video winds up being on museum's website/youtube channel!