SS Chassis with Expanders

[LancerLanesMech]

I haven't had any problems with them until recent. Lane 10 started messing up when cycled, sweep chattering, running half way through without the table moving, cutting in and out the whole time. Damn thing had a mind of it's own. I zeroed it and it ran ok for about 5 mins, then started again. I put on a different chassis and it's been fine for 3 days now so I am thinking chassis, even though the manager's control is still hooked up and I was thinking that might be the cause. Any ideas what might cause this? I haven't tried it on other lanes yet, will be doing so Monday, but thought someone might have ideas i could go with.

[8270king]

Re: SS Chassis with Expanders

Check the pins / sockets.

Put the chassis on another machine.

Install the Mk board and in a different chassis.

Install the expander in another chassis.

See where the problem follows.

[AMFCamMan]

Re: SS Chassis with Expanders

Hey Farley,
Did you check too see if TA was stuck open or partially open in the chassis? I had another center with a similar problem and found it to be a gummy relay.

Jack

[Dutch]

Re: SS Chassis with Expanders

Check to see if there is a piece of metal (screw, contact points that have fallen off, etc)floating around in the bottom of the chassis. If it makes its way over to the heat sink assy & grounds it out, it will cause exactly what you're describing.

While you have the bottom of the chassis off check the resistance on the heat sink diodes. If one is bad, that will cause it too.

[LancerLanesMech]

Re: SS Chassis with Expanders

Thanks guys! Hey Dutch, I'm not the best with a meter, and it's a cheapo digital one. What's the proper method for checking the resistance and what should the reading be?

[TheGMan143]

Re: SS Chassis with Expanders

Diodes are pretty easy to check... basically, it's a one-way valve for power. I don't remember what the exact readings on the power diodes should be in the chassis (that's what books & notes are for :p ), but in most cases, you should get a low resistance in one polarity, and a high resistance in the opposite. I've never really seen a diode 'weaken'... most times, they fail in one of two ways: either they stick 'open', giving you an infinite (or near infinite) resistance in either polarity; or they short closed and give a low resistance in either polarity. {There is a third way that they fail, but it pretty much makes the use of a meter unnecessary... they blow up or crack in half}

One note... in many cases with diodes in a circuit, you will need to 'isolate' (ie: remove from the circuit) one leg of the diode so you're not reading resistance back through the circuit, which can give you a false result.

And (as always), completely remove power from the machine (better yet, unplug the whole chassis or board) before testing circuits... no sense getting an unpleasant (and sometimes dangerous) case of the 'zoomies' from testing live circuits.

Anything I missed, Dutch?

[wb8yjf]

Re: SS Chassis with Expanders

Does your meter have a diode setting? Usually a setting with an arrow ponting at a vertical line. If so, set the meter to that setting and test each diode from the heatsink (what they are pressed into) and the wire of the diode. The outter 2 diodes on the outside will read aprox. .5 on the meter (red on wire, black on heatsink) the center diode will read about the same (reverse meter leads - black on wire, red on heatsink). If ANY of them read either a short (.010 on the meter for example), there is a shorted diode. After u do that, check the heatsink to make sure it isn't shorted to the chassis. Put the meter on a resistance setting of 10K to 100K, if you get a LOW reading, pull the heatsink off and see what the heck is going on. s crews have a tendency to get back behind the thing. ALL that said, I doubt that is the problem! Go down the checklist that king listed. Probably a pin or a relay socket...OR a relay! Junk the antiques and put 3 new relays in!! [img]/content/btubb/images/%%GRAEMLIN_URL%%/laugh.gif[/img]

I have pitched a bunch of screwball antiques relays off of the back wall of a center....they will drive you NUTS. Also, sockets can seem good and really be "so-so" They are a pain in the butt to change, but will also be worth the effort. Usually a M or M2 socket.
[img]/content/btubb/images/%%GRAEMLIN_URL%%/frown.gif[/img] Anyway, you have some fun to look forward to. [img]/content/btubb/images/%%GRAEMLIN_URL%%/eek.gif[/img] [img]/content/btubb/images/%%GRAEMLIN_URL%%/laugh.gif[/img]

Good luck!
Jon [img]/content/btubb/images/%%GRAEMLIN_URL%%/usflag.jpg[/img]

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:p