Skee-Ball Model S Restoration: F2 Fuse Keeps Blowing?

[l1nt]

Hi All, just getting this machine together and my F2 .5amp 250v slo-blo is blowing frequently. I can get the ball release solenoid to work a few times before it acts caught up or just doesn't attempt to fire. I have replaced the solenoid even though the ohms read fine on the old one. I just took apart all the linkage to check for excessively worn parts but all seems well. I cleaned everything up and reassembled. Everything moves by hand very smoothly. Can anyone recommend what to test next?

[lilshawn]

you say it's acting stuck? and you are looking into it being stuck mechanically, despite the fuse blowing.

a mechanically stuck solenoid will not blow a fuse... it would simply just not move properly.

it sounds like it's being stuck ON and being stuck OFF by it's control circuit.

if you get yourself a small incandescent bulb... something like a nightlight bulb. wire it on in parallel with your release solenoid and have it outside the cabinet so you can see it.

actuate your solenoid and make sure it's 110v power is being supplied/turned off appropriately. if it's not being turned on and off properly (which i believe it is not doing it properly) you'll have to look at everything i circled in the circuit... if the resistors check out within specifications, change out the triac.

EDIT: alternatively, if you are unable to source a replacement triac, i can direct you on how to modify the circuit to drive a relay or something... while not ideal, it will work.

[l1nt]

Thanks lilshawn for the feedback. I was assuming binding on the linkage because when it fails and blows the fuse usually there is a slight attempt at pulling back the plunger and then fuse is blown. I already have new replacements for the TRIAC (SC146D) in-case that was the issue. Not sure I have the equipment or know-how to rig a test light but I will see if I can. I will test the resistors in circuit and go from there.

I really appreciate your second set of eyes.

[lilshawn]

no worries. at this point i wouldn't worry about the light... it's just something i suggested to verify the issue.

what i was getting at, and how i processed your issue in your post.... is that nothing electrically changes about the coil, whether the linkage is jammed, or stuck or even not there at all. (in the grand scheme of things) all the solenoid is, is a coil of wire in a circuit.

if there was, say... a chafed section in the coil because of damage or it got overheated and shorted out inside... it can cause the fuse to blow because the expected load of the coil is different to what it's supposed to be.

if, for example... the coil is 100 ohms... at 120v, it passes 1.2 amps... fine for a 2 amp fuse.

but a damaged coil could be something maybe 30 ohms ... this would pass 4 amps. no bueno.

and because you changed the coil out already, and also measured the new coil's resistance against the other, it doesn't seem like there is any issues there. (though i wouldn't discount an issue with the old coil causing the issue with the board triac... high voltage stuff can test good when tested with the low voltage of test equipment like voltmeters... but fail when the full beans get put through it.)

but you said it still does it with the new one as well...

so the fuse still blowing even with a new solenoid is indicating to you that there is an electrical problem further up... citing no shorted to ground cabling issues going back to the board, your issue is likely with the triac since it's in line with the coil...and the coil is known to be good.

capacitors can short out too  which is why i also circled that C15 in the circuit it is also in line with the solenoid to an extent. normally they do not have a "resistance" per se, but they can have leakage and fail, (usually short circuit) causing current to pass through them. i'm not sure why it's there in circuit, probably something to do with biasing the triac or changing some property of it's switching or something like that....  i'm old, but triacs are even really before my time in electronics... and we don't even really use them anymore, so i haven't bothered to look into them much.

[l1nt]

will report back once I pull board and test. thanks again for your opinion and passing on some wisdom!

[lilshawn]

not a problem. everyone here has varying amount of abilities... from nothing... to greybeard gurus.... and everything between. alway helps to pass on some knowledge and post it publicly in a place like this for people to search across when they have their own problems.

nothing sucks more than finding a post where someone was like oh i have this problem.... and it's the EXACT problem you are having and the next post is

nvm i figured it out

or the next post reads:

[USER HAS DELETED THEIR ACCOUNT]

and the next post...

THANK YOU THAT WAS TOTALLY IT!!!!!!11!111oneseleven

 

[l1nt]

Well tested both resistors (R40 & R39) and the capacitor (C15) by taking them out of circuit and they test fine. TRIAC was testing at odd ohms and continuity so I replaced it. Put everything back and got three games in before the ball release arm gave a small attempt at releasing balls when starting a game. the fuse was blow again.

Really getting disheartened on troubleshooting this one!

[lilshawn]

are you replacing the fuse with the proper type?, a 0.5a (500ma) slow blow fuse... and not a regular "fast blow" type (AGC)

[l1nt]

Yes, running these: https://www.amazon.com/dp/B078QL4KQW?ref=ppx_yo2ov_dt_b_product_details&th=1

[lilshawn]

okay, so i did some digging...

that solenoid, (2005-m-1) has some specifications that read as follows...

Johnson Electric 2005-M-1 Solenoid - 120VAC, 60Hz, Continuous Duty, 20.50 Ohms, 17.9W

now... if we plonk 20.5 ohms and 120v AC at 180 degrees phase angle into an AC current calulatormajigger we be looking at about 5.8 amps of peak current for that solenoid. this is assuming it never changes, but it does since it's a reactive device. so it may spike up to that, but settle lower after it's activated.

some other sites state it's value is somewhere about 4.8 amps draw... soooooo...

it may be worth it to bench test this solenoid with your volt meter setup for AC current reading and measuring the actual current draw of it. it may be that the although the schematic appears to have written ".5A" fuse... it could be perhaps, supposed to be a 5A fuse and the dot is an artifact of that documents age before it was scanned.. it may not be related.... who knows.... so unless another document or tag or something in your machine says that that fuse is supposed to be "0.5A" or "500mA" (like silk-screened onto the board or on a tag in the cabinet somewhere), a solenoid of that low of a resistance, by all rights... should have a larger fuse than 0.5 amps since it would obviously draw much more than that.

so, it's entirely possible the whole issue here... is simply... an improperly spec'd fuse.

using a 5 amp (slow blow) fuse on a circuit hauling 4.8 amps is perfectly spec'd. a slow blow MDL fuse can take 100% of it's rated load... indefinitely... and 200% of it's load for anywhere between 3 and 5 seconds before blowing.

so, dear watson you ask what to do?... yes, by my deductions, assuming this solenoid is the one originally in the machine... and knowing nothing and ignoring anything anyone may have done previously to the machine... and bench testing the solenoid's actually load (assumed to having a 4 or 5 amp load when activated)

a 5 amp slow blow fuse would be what is needed here, not a 0.5 amp.

*drops mic them promptly picks it up again and puts it away properly*

[l1nt]

I have confirmed .5 slo-blow is the correct fuse here. I picked this machine up as-is from the former Skee-Ball world champ and he run several dozen of these machines up and down California. He confirmed that is the fuse for F2. Might be time to find someone local with boots on the ground to look at it. I appreciate your help and humor!

[lilshawn]

if you aren't worried about keeping things original, i would have the output of the board go to a small 120v relay which would use much less power than the solenoid... and have the relay drive 120v to the solenoid.

i would use something like linked: (sorry for obscenely long amazon link)

https://www.amazon.ca/Tnisesm-Miniature-Power-120VAC-NT90-AC120V/dp/B08TR7WJX2/ref=sr_1_9?crid=ZVM3Z77T4OJI&dib=eyJ2IjoiMSJ9.mUDNdNEP0Yv21U8JsS9--oXC8MN_V8UUqRyG9pRG1hHDLWz233wqaVtiqDATOj9I9-0BibeY8msrDIKbYhnFmq9d3xOccxOGoHNKeXpvHfAE0Taun9krYJ3vrw3Y3xpWXlSnNZt0TSnBJYCo58F-yu48qUuJEmdMkFXPOWDl0Jt71YBWKWh1by2v37sbDpfQwKRv3mUDtqXw-VHb1DNUk7pYHRiV-lk2kl3i5InLOFMJCwxcAt-xb9kgMChey8U0KaiV_qhFwTcWi8JkU1xSjbX7Oxg2WScvenPLOjpkagw.Yz1Umrm-usfP1cXR_68MTUVSZmeGzUicowOS_uwGPq8&dib_tag=se&keywords=120v+relay&qid=1712164591&sprefix=120v+relay%2Caps%2C473&sr=8-9

or i would modify the circuit to drive a mosfet/solid state relay and get away from the triacs