Re: How do i check the clock circuit?

Thanks John, Yes I have a logic probe coming in the mail, I never thought
to check to see if my DMM has one built in, but hey a man can never have
enough tools...........>AMMARIGHT????

On Tue, Sep 24, 2013 at 11:48 AM, John Robertson <pinball@telus.net> wrote:

> On 09/24/2013 11:20 AM, Joel Griffin Dodd wrote:
>
> Thanks Ed.
>
> So far I have verified all voltages on the PSU and AR2 boards and they
> all fall within the required specs.
>
> Next I do indeed plan to make my way through all of the socketed chips
> for cleaning and reseating.
>
> I'd invest in a Logic Probe for your first tool. There might even be one
> built-in to your DVOM (Digital Volt Ohm Meter). This will either use
> blinking lights/LEDs or beeps/chirps to indicate the presence of digital
> signal (High/Low) on the trace in question.
>
> I find the old HeathKit logic probes to be the best, although I have a
> pile of Kurz-Kasch probes that we also use when the HK probes are all
> hiding.
>
> Read up on using Logic Probe, heck there are kits to make your own (great
> practice!). It is the first tool I had years ago and it is still one of the
> first I turn to for checking things like Clock, Reset, and other critical
> signals.
>
> As I went on I got a few more tools...and even started a mail list on tech
> tools. Which seems to be mostly Fluke gear these days - but that is another
> story.
>
> John :-#)#
>
>
> On Tue, Sep 24, 2013 at 10:34 AM, Ed Henciak <ehenciak@gmail.com> wrote:
>
>> Hi Joel,
>>
>> Sorry for the delayed reply.
>>
>> You might want to insure your power supply is completely stable
>> first and foremost. A bad power supply can cause even more damage to the
>> main board.
>>
>> Atari does a pretty good job detailing the voltages you should
>> expect to see. I'd disconnect the main board from the power supply first
>> and make sure the voltages look reasonable. If you want to "overkill fix"
>> your power supply, you might want to replace the electrolytic caps on the
>> power supply. They can be had for fairly low prices. Also, someone out
>> there may sell a "get well kit" for Atari power supplies. These are
>> similar to those kits of electrolytic caps and deflection transistors for
>> vector monitors.
>>
>> I'd certainly start there if you're not that well versed in PCB
>> repair :-). If you blow that power supply board up, it's a heck of a lot
>> easier/inexpensive to shotgun replace every component on a power supply vs
>> doing the same on a main boards for a video game :-).
>>
>> One other suggestion ... a friend reminded me of this ... you
>> should pull all socketed chips from the mainboard, clean the legs off, and
>> reinsert them. The electrical connections in sockets get pretty gnarley
>> over time. Use something like a pencil eraser to get the gunk off and
>> clean up residue with a bit of rubbing alcohol on a cotton swab. I would
>> also clean off the edge connectors with alcohol/cotton swab.
>>
>> And one other thing ... you might want a bench top power supply when
>> you move to debugging the main board. The power is cleaner and more
>> stable. I forget the voltages required for Star Wars though they can be
>> found on the schematics. A bench top supply isn't 100% necessary, but it
>> certainly helps a lot!
>>
>> Ed
>>
>>
>>
>> On Tue, Sep 24, 2013 at 12:05 PM, Joel Griffin Dodd <
>> griffindodd@gmail.com> wrote:
>>
>>> Pat. Yep I have no illusions about what I am taking on, and maybe I will
>>> get to the point where I just have to know I am beat.
>>>
>>> I am documenting my experiences over at KLOV in the hope that anything
>>> I learn is of benefit to others in my shoes, even if that lesson is 'know
>>> when to fold em'.
>>>
>>> Talon2000 over at KLOV has agreed to give me coaching via PM as I try
>>> and progress, this is good as he is considered an excellent repairer
>>> especially with regards to these boards.
>>>
>>> For me this hobby has always been about pushing myself to learn new
>>> things and stretch my abilities, I really do enjoy that aspect and whether
>>> there are victories or losses I always have fun on the journey. Heck, I
>>> never would have thought I could have built a color XY from scratch, but
>>> this passed weekend I fired up my creation and she is working, such a
>>> thrill and very satisfying.
>>>
>>> Here's the KLOV thread following the board repair part of my journey.
>>> http://forums.arcade-museum.com/showthread.php?t=288626
>>>
>>>
>>> On Tue, Sep 24, 2013 at 8:58 AM, Joel Griffin Dodd <
>>> griffindodd@gmail.com> wrote:
>>>
>>>> Thanks for all the feedback guys.
>>>>
>>>> I'll definitely look into a solder reworking station if I start to
>>>> need to remove unsocketed chips.
>>>>
>>>> I am currently looking for a nice used O-Scope but I'm having to
>>>> learn what functions I will need it to perform so I don't get something
>>>> unsuitable. So far I just know that 100mhz and above is good and an XY
>>>> input is a nice added option for vector work without monitors.
>>>>
>>>>
>>>> On Tue, Sep 24, 2013 at 8:48 AM, Jimmy Ipock <jipock@gmail.com> wrote:
>>>>
>>>>> I would highly recommend at least a low end oscilloscope. It made
>>>>> troubleshooting my space duel vastly easier. Plus, you can hook it to the x
>>>>> and y out and play the game sans vector monitor ;>
>>>>>
>>>>> I actually found a reasonably good one on ebay for 60 bucks once..
>>>>>
>>>>>
>>>>>
>>>>> On Tue, Sep 24, 2013 at 9:52 AM, Pat Danis <patdanis@verizon.net>wrote:
>>>>>
>>>>>> Joel:
>>>>>>
>>>>>> I salute your dedication in attempting to get your board set
>>>>>> working. You might have considered starting on something a little bit
>>>>>> easier. I have been doing this for at least 10 years and my skill set at
>>>>>> fixing boards is what I consider "very basic". That is, running the self
>>>>>> test and replacing chips identified as bad. After that, if you do find
>>>>>> something that is wrong, chances are you will not have the parts you need
>>>>>> to fix it. There are the very common chips scattered throughout he board
>>>>>> that are easy to find, it is the unique parts that might give you the fits.
>>>>>>
>>>>>> If you do find the problem, you need to be certain you know what you
>>>>>> are doing when replacing chips. Can you cleanly desolder chips without
>>>>>> ripping pads or traces and reinstall a socket? If not, You might stop now
>>>>>> and consider sending the board off to a "pro" (Not me) and let them tackle
>>>>>> it. It costs more in the long run for them to fix other people's screw
>>>>>> ups. It is certainly admirable to learn to fix things yourself but it
>>>>>> might be better to start on a simple board like a pacman etc.
>>>>>>
>>>>>> There is a Star Wars trouble shooting guide available and a ton of
>>>>>> information on the web about star wars issues. Who knows, you might get
>>>>>> lucky and find the problem and change a chip and be up and running. (I
>>>>>> doubt it) Based on my experience with SW board sets, you have a long road
>>>>>> ahead of you. I know two guys who fix them and I consider them brainiacs
>>>>>> when it comes to board repairs. They still have problems sorting out all
>>>>>> the issues.
>>>>>>
>>>>>> Best of luck in your endeavors.
>>>>>>
>>>>>> Pat
>>>>>>
>>>>>> On 9/24/2013 8:32 AM, Joel Griffin Dodd wrote:
>>>>>>
>>>>>> Thanks guys, the info on spotting a clock visually was especially
>>>>>> helpful. Sometimes the skill level of guys that have been doing this work
>>>>>> for such a long time skips past many of the most basic yet useful pieces of
>>>>>> information that a newbie simply doesn't yet know. Now at least I know what
>>>>>> to look for on the PCB in the 'real' world as well as the schematic.
>>>>>>
>>>>>>
>>>>>> On Tue, Sep 24, 2013 at 2:08 AM, Andre Huijts <a.huijts@upcmail.nl>wrote:
>>>>>>
>>>>>>> The clock signals are generated using crystals. They are easy to ID,
>>>>>>> usually a flat aluminum colored can:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> More modem versions look like this, if you see these, the crystal
>>>>>>> has probably been replaced in more recent years:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> This may sound weird but your first work should be visual. Check if
>>>>>>> the crystals are there at all and if they are still firmly soldered. I
>>>>>>> actually started measuring for a clock signal only to discover some
>>>>>>> seconds later that it was missing :) The crystals often get damaged or
>>>>>>> broken off during stacking PCBs or transport because they stick out high
>>>>>>> above all the other parts. This is also why I prefer to replace them with
>>>>>>> the smaller modern types.
>>>>>>>
>>>>>>> A general visual inspection is always a good idea. Look for damaged
>>>>>>> tracks, bad sockets etc. in case of SW PCB set, make very sure the
>>>>>>> interconnection board is on really tight.
>>>>>>>
>>>>>>> Verstuurd vanaf mijn iPad
>>>>>>>
>>>>>>> > Op 24 sep. 2013 om 10:49 heeft Andrew Welburn <
>>>>>>> andy@andysarcade.net> het volgende geschreven:
>>>>>>> >
>>>>>>> > You need to get the manual and schematics and read them, they you
>>>>>>> will know where all these things are...
>>>>>>> >
>>>>>>> > Andrew Welburn
>>>>>>> > http://www.andys-arcade.com
>>>>>>> >
>>>>>>> >> On 23/09/2013 23:33, Joel Griffin Dodd wrote:
>>>>>>> >> Thanks Ed!
>>>>>>> >>
>>>>>>> >> No problem on waiting for the probe to arrive, I'm moving house
>>>>>>> this
>>>>>>> >> week so I have plenty to keep me busy.
>>>>>>> >>
>>>>>>> >> How do I physically identify a clock/chip/oscillator on a board?
>>>>>>> Also
>>>>>>> >> how do I know which line out is the clock line?
>>>>>>> >
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>>>>>>> chris@westnet.com
>>>>>>>
>>>>>>>
>>>>>>
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>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>
>
> --
> John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
> Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
> www.flippers.com
> "Old pinballers never die, they just flip out"
>
>

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Received on Tue Sep 24 14:51:10 2013