Fast, slow, and "normal" blow fuse? - FIXED!

TheYeti

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Fast, slow, and "normal" blow fuse? - FIXED!

I have a Kortek KT-1420A chassis inside my Pac-Man. The other day I was adjusting the flyback and it developed a pin-sized hole near the focus POT and thus...arched to the frame and shut off the monitor.

I removed the chassis and I think that I can plug the hole with some silicone glue or epoxy.

However, I also noticed that one of the 2 fuses on the chassis was blown. (Probably when the flyback arched to the frame)

The fuse is labeled F602 and it is a 250v 1a 5mmx20mm fuse.

My question is this:

How do I know if this fuse is a fast, slow, or normal blow fuse?

I think it might call for a normal blow fuse but if I put a slow blow fuse in there, will it hurt anything?
 
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and I think that I can plug the hole with some silicone glue or epoxy

(Probably when the flyback arched to the frame)

How do I know if this fuse is a fast, slow, or normal blow fuse?

I think it might call for a normal blow fuse but if I put a slow blow fuse in there, will it hurt anything?

whats his name said to use bubble yum and only bubble yum in the hole

number of ways to tell and do not put a slo blo in there where a fast blo should be. I mean you can, if you are doing troubleshooting or whatever but as a rule you want a fast acting fuse in some circuits so as to protect components and a slo blo in there as well where its needed
the slo blo you want like in the main fuse, when you turn the game on there is a rush of electrons through when the whole thing power up and you don't want a fast blo fuse in there, we want a slo blo to let extra electrons in and then the rush subsides

on the end of the fuse, printed in the metal end it should tell you what it is
AGC is fast blo
MDL is slo blo
I would verify what fuse by looking in the manual
don't go by what is installed as someone mighta put in the wrong fuse and then you came along

replace flyback and probably the voltage regulator too. hopefully the fuse kept other parts from dying
 
whats his name said to use bubble yum and only bubble yum in the hole

number of ways to tell and do not put a slo blo in there where a fast blo should be. I mean you can, if you are doing troubleshooting or whatever but as a rule you want a fast acting fuse in some circuits so as to protect components and a slo blo in there as well where its needed
the slo blo you want like in the main fuse, when you turn the game on there is a rush of electrons through when the whole thing power up and you don't want a fast blo fuse in there, we want a slo blo to let extra electrons in and then the rush subsides

on the end of the fuse, printed in the metal end it should tell you what it is
AGC is fast blo
MDL is slo blo
I would verify what fuse by looking in the manual
don't go by what is installed as someone mighta put in the wrong fuse and then you came along

replace flyback and probably the voltage regulator too. hopefully the fuse kept other parts from dying

Thank you very much. This is very helpful info. I'm going to have to track down some bubble yum!

Just so that I fully understand....there are only 2 types of fuses: fast and slow blow right?

If someone says "normal" blow...what are they actually saying?
 
OK, so I found 2 versions of my chassis' manual online. I found the section for the fuse specifications. Both versions are shown below. Can anyone tell me if F602 is a fast or slow blow based on the highlighted rows?



 
Ken Layton's repair guide says 1A fast blo and since that was already there I would go with that. He also shows how you can minimize the arcing to the cage around the FBT by cutting some of the cage away.

http://www.arcade-museum.com/manuals-monitors/Kortek_KT1420A_repair_guide.pdf

Perfect thank you for confirming the FAST blow fuse! I guessed and ordered some yesterday. In his guide he says "normal" blow and I didn't understand that.

I've actually already started the process of epoxying the flyback last night. I slathered it on. I don't have the means to cut back the cage at the moment so I'm going to gamble and just over-apply the epoxy to see if that works! Wish me luck!

(All that white residue on the side of the FB is just leftover duct tape glue. The previous owner had a strip of duct tap on the FB so I removed it. Hmmm, now I know why!)

 
not always but generally speaking when you have a fuse listed in the monitor and game manuals and they don't specify fast or slow blow than its a fast blow fuse. most of the time if you have a required slow blow it will state MDL or slow blow or SB, but for some reason they don't designate FB or fast blow in the manuals, schematics, etc.
 
not always but generally speaking when you have a fuse listed in the monitor and game manuals and they don't specify fast or slow blow than its a fast blow fuse. most of the time if you have a required slow blow it will state MDL or slow blow or SB, but for some reason they don't designate FB or fast blow in the manuals, schematics, etc.

Good to know! thank you security0001!

By the way, I'd just replace this flyback but I don't think anyone sells it anymore.

It's a real shame too because I have it paired withe an RCA tube with very little burn. I'm scared this chassis is a ticking time bomb now. It's only a matter of time before I'm SOL. :(
 
Technically it's oversimplifying, but I like to think of it as there being basically two kinds of fuses for arcade stuff, normal and slow. Normal is only considered 'fast' because of the existence of slow, as there are more cases where you need a fuse to tolerate short-term surges in current (slow blow), than cases where you explicitly need a fuse that will blow faster than usual (which isn't typically the case, for our purposes).

So basically, all fuses are normal, unless they explicitly call for slow.
 
FWIW, I used silicone glue to plug a hole in a k7000 flyback. It was still in service some 7 years or so later and thats being on 16/7
 
About the size of the head on a ball point pen. 1/16th to an 1/8 maybe.

Ok, cool...that's exactly the size mine was. Right on the corner of the FB near the focus POT.

Pretty facinating that a hole can be drilled through plastic by electricity..all on it's own.

Did they just use crappy plastic on flybacks? Or were the walls really thin? Maybe the plastic gets brittle over time?
 
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plastic dries out and micro fractures form. High voltage electricity is like water under pressure. If theres a way out it will find it.
 
I'm back in business! Thanks to everyone that helped me understand fuse terminology.

Popped a new fast blow fuse into my chassis, slathered on the epoxy, put everything back together and fired it up! Looked like crap at first but then I dialed in all the pots. The picture is gorgeous now. Crossing my fingers this chassis runs for years to come!

 
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