Re: Tempest problem.

Well I never looked at the ls139 at B3 before. Didn't occur to me for some
reason. But Pin5 b3 is stuck high. As for the W4 jumper those are hard wired
with traces, not like some of the later boards. C1 Pin 14 ohms out to K2 pin
4, and is not tied to ground. So that checks out for W4.

Previous while trying to trouble shoot this I had pulled and checked, H3,
K2, L2, C3, and J5 and still no joy.

I don't have my IC checker handy so I went ahead and replaced B3 no change.
Pin 5 still high. Pin 1 toggles, 2 Low, 3 Toggles. Looks like those signals
come from pins 23-25 from the CPU.

So that's where I currently am.. Looks like I need more coffee :)

Kevin

On Tue, Nov 17, 2009 at 8:10 AM, Andrew Welburn <andy@andysarcade.net>wrote:

> Is /VMEM asserted when read/writing the vector ram 2000 -> 2FFF? pin5 B3
> ?
>
> H3 is your data buffer for all vector rom/ram, make sure its good (you may
> have already)
>
> For an -02 pcb, W4 jumper should be installed, connecting C1 pin 14 to
> signal AM11 (K2 pin 4) this affects the reading of vector rom at 3000 ->
> 3FFF.
>
> Half your problem might be that W4 jumper issue, but you say vector ram is
> also affected, check K2, L2, C3 and J5 (sheet 3 side A)
>
> enjoy
>
> Andrew Welburn
> www.andys-arcade.com
>
> ----- Original Message -----
> *From:* Kevin Moore <talon.k@gmail.com>
> *To:* vectorlist@vectorlist.org
> *Sent:* Tuesday, November 17, 2009 1:55 PM
> *Subject:* Re: VECTOR: Tempest problem.
>
> I just wish the other tempest board I'm working on was as forgiving.
>
> It won't boot, something isn't right with the Vram, and Vrom addressing.
> Using the fluke I can read all the roms and check the normal game ram just
> fine. But can't read the vroms or do a mem check on the vram. The buffers
> appear to toggle just fine when trying to access with the fluke, (in normal
> game run they don't toggle at all) I went ahead and replaced them still no
> joy.
>
> It's a rev 2 board it looks like, and the w4, and w2 jumpers aren't
> present. So I'm still kinda at a loss.
>
> When I put it in test mode, I get one short low tone and nothing. Still
> probing around trying to figure out where the problem is..
>
> Kevin
>
>
> On Tue, Nov 17, 2009 at 7:48 AM, Andrew Welburn <andy@andysarcade.net>wrote:
>
>> heh, those kinds of faults where you can kickstart a stuck node are very
>> rare, i've done maybe 3 of them in 10 years, and only one of them later
>> failed... one was on an asteroids, one was on a battlezone, and the other
>> was on a more modern game i forget what it was, but it was that one i had to
>> revisit and replace the offending IC.
>>
>> So i'd say you have a 33% chance of it re-appearing, but at least yuou
>> know exactly where to look if it does re-appear.
>>
>> Andrew Welburn
>> www.andys-arcade.com
>>
>> ----- Original Message -----
>> *From:* Kevin Moore <talon.k@gmail.com>
>> *To:* vectorlist@vectorlist.org
>> *Sent:* Tuesday, November 17, 2009 1:37 PM
>> *Subject:* Re: VECTOR: Tempest problem.
>>
>> Yeah, I just hit it with +5v and it started toggling. The problem hasn't
>> come back even through power cycles. It's been running just fine for the
>> past 12+ hours. Which seems odd to me, so I'm going to keep an eye on it for
>> a while longer.
>>
>> Kevin
>>
>>
>> On Tue, Nov 17, 2009 at 7:27 AM, <kstillinger@sc.rr.com> wrote:
>>
>>> Hey Kevin-
>>>
>>> What exactly do you mean when you say you 'toggled' the pin?
>>> Did you force it high with a momentary short to 5V? If so, did it start
>>> making the appropriate transitions afterwards? Does the problem re-appear
>>> after power cycling?
>>>
>>> Just curious and looking for more info.
>>>
>>> Kerry
>>>
>>> ---- Kevin Moore <talon.k@gmail.com> wrote:
>>> > Thanks Andrew. I have the alt circuit with the MC3410. Pin 4 was stuck
>>> low.
>>> > Toggled it, and the problem went away. I'm sure the problem will come
>>> back,
>>> > When it does, I'll have to check the proceeding circuit to see if the
>>> > problem is with the 3410, or somewhere before. But at least I know
>>> where the
>>> > problem lies.
>>> >
>>> > Thanks very much for pointing me in the right direction.
>>> >
>>> > Kevin
>>> >
>>>
>>>
>>> ---------------------------------------------------------------------------
>>> ** Unsubscribe, subscribe, or view the archives at
>>> http://www.vectorlist.org
>>> ** Please direct other questions, comments, or problems to
>>> chris@westnet.com
>>>
>>
>>
>

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Received on Tue Nov 17 10:15:20 2009