Re: How do i check the clock circuit?

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.

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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>>>>>> > ** Please direct other questions, comments, or problems to
>>>>>> chris@westnet.com
>>>>>>
>>>>>>
>>>>>
>>>>> ---------------------------------------------------------------------------
>>>>> ** Unsubscribe, subscribe, or view the archives at
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>>>>> or problems to chris@westnet.com
>>>>
>>>>
>>>>
>>>
>>
>

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Received on Tue Sep 24 14:20:49 2013