Who can spot what they've done wrong here? - Page 1
Forum section: electronics / general

author: Sonny_Jim
author_rank: Unknown
timestamp: April 19, 2016, 01:03:46 am
content: We'll start with this pic:Free internet cookie for the first one to spot it.EDIT: Uncropped picture is here:http://www.pinballnews.com/games/fullthrottle/306a.jpg

author: sleemanj
author_rank: Super Contributor
timestamp: April 19, 2016, 01:05:21 am
content: Glued over the top of the capacitor vent scores.

author: tom66
author_rank: Super Contributor
timestamp: April 19, 2016, 01:16:30 am
content: The space between the 2kV insulated side and rest of the board appears to be violated along top edge of board, but may be a photo/lighting effect.The LEDs look brighter than the Sun itself, and one of them appears to operate off 70V, which is quite a lot of power to be potentially dissipating across a small SMD resistor.

author: Sonny_Jim
author_rank: Unknown
timestamp: April 19, 2016, 01:17:03 am
content: Ding ding ding, free internet cookie for you sir. And what do you think is going to happen when those caps fail? The worst part is that they seemed to have done this on *every* cap on their boards.And now the bonus round. What else can you spot that isn't 'best design practice'

author: sleemanj
author_rank: Super Contributor
timestamp: April 19, 2016, 01:34:53 am
content: Ahh, a pinball machine, they always seem to look like bodged together abominations inside :-)

author: tom66
author_rank: Super Contributor
timestamp: April 19, 2016, 05:04:50 pm
content: Bolt thru the toroid - gotta be careful not to create a shorted turn with adjacent wires.

author: Yansi
author_rank: Super Contributor
timestamp: April 19, 2016, 05:15:16 pm
content: Looks more like a machine full of mess to me than a pinball one

author: wraper
author_rank: Unknown
timestamp: April 19, 2016, 05:20:37 pm
content: Quote from: tom66 on April 19, 2016, 01:16:30 amNo it's not, there is no copper trace at the edge. PCB looks brighter on the edge because of the internal copper layer keepout from the edge.

author: dmills
author_rank: Super Contributor
timestamp: April 19, 2016, 07:39:39 pm
content: Pinball machines are usually a dogs dinner, no real idea why.The earthing looks 'interesting' in that headboard, clamping multiple earths under a PCB board mounting screw is hardly good practise, and what is that insulating taped connection doing?Regards, Dan.

author: Kjelt
author_rank: Super Contributor
timestamp: April 19, 2016, 07:51:00 pm
content: No sleeve or other form of protection to the bunch of wires that are held together.No tensionreleave for the mains wires and secundary power leads.No protection cap on the mains connection of the dc-dc smpsupply.Bridge rectifier has no coolingMain ground star point is on a pcb instead of somewhere on the cabinet itself.The wiring in total is a mess.What pinball brand is this crap?

author: Sonny_Jim
author_rank: Unknown
timestamp: April 19, 2016, 10:27:28 pm
content: All valid points. What concerns me the most about this cabinet is the total lack of 'respect' for cable routing and management, in particular the mains wiring.The exposed terminals on the PSU are bad, because bearing in mind this is a pinball machine, any owner will tell you screws/bits of metal can fall off the playfield and into the bottom of the cabinet due to vibration. I'd hate to see what would happen if a screw fell on the terminals on the PSU, because I couldn't see a fuse for it. I couldn't see a MOV anywhere either.QuoteI believe that it's for the 70V coil line, so maybe they can get away without having a heatsink.QuoteQuoteThis is going to be a stupid question, but why on the cabinet instead of a PCB?QuoteNot quite sure what you mean with this. How would the bolt create a short? (sorry if it's obvious)I think everyone can agree that it's just a mess. What makes this worse was that they knew that a reporter was coming in to look at it and take photos and didn't seem to think it needed tidying up.If you want to have a look at a review and some more pictures here's the link, I'd be interested to see what you guys think:http://www.pinballnews.com/games/fullthrottle/index11.html

author: Monkeh
author_rank: Super Contributor
timestamp: April 19, 2016, 10:34:33 pm
content: Quote from: Sonny_Jim on April 19, 2016, 10:27:28 pmPCBs are quite compressible. What feels tight today, may not be tomorrow.Earthing star points should be on a metal chassis or between two nuts.

author: nogood
author_rank: Contributor
timestamp: April 19, 2016, 11:27:43 pm
content: Well unless you look under the gunk you can't be sure that there even are scores.Or are those without only the very small and larger eletrolytic caps (popping the base instead) ?I think I remember seeing some medium sized ones in older tech though...That said, on at least one you can still see 3 score lines on top. So probably not.

author: Yansi
author_rank: Super Contributor
timestamp: April 19, 2016, 11:52:42 pm
content: I think the glued tops of the ellytics will be one of the least safety issues in that wire maze.

author: Sonny_Jim
author_rank: Unknown
timestamp: April 20, 2016, 12:55:42 am
content: QuoteAh of course, makes sense when you think about it. Thanks for explaining that to me.QuoteUnfortunately it's just the 'nature of the beast'. A pinball table has something like 60-odd switches (arranged into a 8x8 matrix), 60+ lights (again matrixed) and 20+ coils/motors/flashers, so there's always going to be a rats nest of cables. It's amazing that Williams managed to get the looms looking as tidy asthisall things considered.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 20, 2016, 11:53:03 am
content: as someone said... "so its nothing new here"... poor lady

author: Synthetase
author_rank: Regular Contributor
timestamp: April 20, 2016, 12:05:26 pm
content: Quote from: Sonny_Jim on April 19, 2016, 10:27:28 pmSince the windings of a toroidal transformer go through the centre of the device, it is possible to create a 'shorted turn' using the bolt that goes through the middle by electrically connecting it at each end using the chassis. You get a lot of current flow and heat produced and can overload the transformer.It's a not-uncommon problem among amateur amplifier builders. Not going to be an issue in this case because it looks like there's plenty of clearance between the top of the bolt and the pinball play area (which is probably made of perspex anyway?).

author: grumpydoc
author_rank: Super Contributor
timestamp: April 20, 2016, 12:30:31 pm
content: Quote from: Mechatrommer on April 20, 2016, 11:53:03 amTo be fair to the poor girl that's about where I'd want to grip an iron it order to get fine control of what the business end was doing.I'd just not want to use a monster of an iron like that on anythng smaller than about 12 guage wire.

author: rrinker
author_rank: Super Contributor
timestamp: April 20, 2016, 01:14:07 pm
content: I built a whole computer (well, assembled a kit on a pc board) with an iron about that size when I was 13. It still works today, 36 years later.I only acquired a proper temperature controlled soldering station in the past 8 or 9 years - and instantly wondered why I took so long to just buy the right tool. But I always made do with a collection of simple irons and a heavy duty gun for the really big stuff - 15 watt, 25watt, and 40 watt irons and a 200 watt gun. When I was a kid, we just had one iron about that size, 40 watts I think it was, plus a heavy gun. Somehow I managed to build the computer without delaminating the traces or melting any of the through whole passives. Thankfully EVERY chip is socketed so all I had to worry about was melting the plastic on a socket.The toroid thing is a huge potential trap for younger players. Remember in one of the power supply teardowns Dave did, it appeared the manufacturer fell flat into the trap, but a close up shot revealed the insulating bushing that prevented solid metal contact between the bolt and the mounting bracket that otherwise would have cause the very issue mentioned. Even if mounted to a metal surface, there could be the same thing going on here - though from the pictures plus descriptions of the typical innards of pinball machines by others - I kind of think they more or less got lucky by not bolting it to a metal bracket.

author: Sonny_Jim
author_rank: Unknown
timestamp: April 20, 2016, 02:38:07 pm
content: Ah I see how that could catch you out. I think in this case they'll get away with it as the cabinet is wooden.QuoteNope, they are still wooden, with some kind of 'special' coating on the topside of the surface to help with wear.