Re: Tempest foldover on right side

Well I'm now officially away for the holidays. So measurements will have to
wait till next monday.. But this is some good info to check up on.

Thanks

Kevin

On Tue, Dec 22, 2009 at 9:10 PM, William Boucher <boucher@mnsi.net> wrote:

> I'm finding this thread very interesting. I think that Zonn and Matt
> have made excellent suggestions. Matt's idea that the input signal is being
> clipped is certainly possible and should be easy to verify on a scope.
>
> Zonn's idea is that maybe one of the DC power rails is too low and causing
> the drive transistor to saturate too early. We saw from the video that the
> walling effect was happening on just one side of the short axis (is that "Y"
> ?). I don't know off the top of my head if that side of the monitor points
> toward the positive or negative DC supply but obviously it's one or the
> other. My point is that if either DC supply (+ or -) was too low, it would
> cause the same walling effect on one side of both axis' I expect. Since the
> problem is only on one axis, I suspect that the DC supplies are both okay.
>
> Say you now go and measure both supply voltage's at J600 pins 1 and 7 and
> that they are at the nominal levels +27.8V and -27.7V respectively. This
> would prove that just one side of just one amplifier has a problem. Let's
> now say that we are going to focus on the "Y" axis and assume that only one
> side has a problem. If it's the negative side, check R609 and R613. These
> are very low value resistors. Does one looked a little cooked? Maybe its
> value has increased such that the DC supply to the emitter of Q604 is too
> low and now Q604 cannot pull the base of the main driver Q606 low enough to
> generate full deflection. Perhaps one of the diodes D600 or D601 has
> shorted. These are biasing components for Q602 and Q604. This would
> severely limit the ability of Q602 and Q604 to turn on sufficiently to
> generate full deflection in the negative direction. If the problem happens
> to be on the positive side, I'd check or replace any component that could
> limit the ability to fully turn on Q603 such as R611 and R612 (maybe cooked
> and now value is too high).
>
> Beyond the components that I have already mentioned above, the obvious
> recourse is to replace the small TO-92 style transistors (Q600, Q601,
> Q602) in the amplifier or either Q603 or Q604 depending on which supply side
> we're talking about (+ or -).
>
>
> William Boucher
>
>
> ----- Original Message -----
> *From:* Andre Huijts <a.huijts@upcmail.nl>
> *To:* vectorlist@vectorlist.org
> *Sent:* Tuesday, December 22, 2009 3:49 PM
> *Subject:* Re: VECTOR: Tempest foldover on right side
>
> Hold on. The video of the scope you saw is actually _my_ cockpit, the
> WG6100 issue is on a friend's cockpit. So different board-set, different
> monitor. However, I've ran the WG6100 on my board-set (that works 100% on my
> Amplifone) AND on my spare PCB-set and the effect is still the same. So it's
> definitely a monitor issue.
>
> I will try your suggestion as soon as I visit my friend. What if it doesn't
> reach it ? Transistors ?
>
> Op 22 dec 2009, om 08:50 heeft matt het volgende geschreven:
>
> sorry i just saw the scope x-y mode and i can see that box!!
> so the game pcb is fine :P
> its in the monitor some thing is stoping the over scan!
> set the scope to DC and look at the head room on the X yoke eg.
> +30V __
> / \
> _/ .....so on
> 0v__ /
> \ _/
> \ /
> -40 \/
> and see if the + and - are the same peek voltage
>
> thanks matt
>
>
> ----- Original Message -----
> *From:* matt <galaga@slingshot.co.nz>
> *To:* vectorlist@vectorlist.org
> *Sent:* Tuesday, December 22, 2009 8:34 PM
> *Subject:* Re: VECTOR: Tempest foldover on right side
>
> have you turned off overscan on your zvg??? I can see the white box that's
> men't to make your screen flash white.
> or the game is not overscaning?
> i will try to draw it
>
>
> ______________________________
> ______________________________
> || ||
> || . . ||
> || ||
> || this "." are the ||
> || bule dots on the ||
> || game screen ||
> || ||
> || ||
> || ||
> || . . ||
> *|| ||*
> ______________________________
>
> the ___ and || are that white flashing you get when you get hit
> you can see this best on a scope x-y mode
>
> x-y----- Original Message -----
> *From:* Andre Huijts <a.huijts@upcmail.nl>
> *To:* vectorlist@vectorlist.org
> *Sent:* Tuesday, December 22, 2009 7:24 PM
> *Subject:* Re: VECTOR: Tempest foldover on right side
>
> Just wanted to mention I posted about exactly the same issue with a 6100 I
> worked on before. It's on a SW cockpit running a low-res 25" tube. The
> "walling" (which is a good term for this error) happens on the left side
> (instead on top like Kevin's video shows) but in case of a vector that's all
> pretty much the same.
> This is also with a 314 board without the protection board (but I installed
> the first basic Atari suggested protection mod diodes). It also has the
> LV2000 installed.
>
> I never got a reply back then. I made a video of it too, here it is. The
> walling is esp. visible when you get hit or f.i. when zooming in on the
> death star.
>
> http://www.youtube.com/watch?v=aePHZsifvIA
>
> So, I'm following this with great interest...still gotta fix it.
>
>
>
>
> Op 22 dec 2009, om 04:16 heeft Zonn het volgende geschreven:
>
> Have you checked the voltage coming out of the LV2000, if it were set too
> low, it could have a limiting effect like this.
>
> -Zonn
>
> On 12/21/2009 6:23 PM, Kevin Moore wrote:
>
> Yes I'm referring to the Lv2000 upgrade, I realize it's not the same thing.
> But my board set is the early version P314 and does not have the Protection
> circuit added. So I'm trying to find another cause for this.
>
> Kevin
>
>
> On Mon, Dec 21, 2009 at 6:35 PM, William Boucher <boucher@mnsi.net> wrote:
>
>> Are you referring to the popular LV2000 (or similar type) "protection"
>> board? This is not the same thing and doesn't provide the same mode of
>> protection. The popular "*input* protection" board eliminates
>> the possibility of over-stressed discrete transistors in the low-voltage
>> power supply section in the case of a monitor with no signal applied for an
>> extended period. It does this by providing proper voltage regulators
>> instead of those transistors.
>>
>> The "protection" circuitry of the P327 deflection board (and previous
>> versions with the very long add-on board) creates individual and
>> time-sensitive current limiting circuits for the main output transistors.
>> If you remove the diodes and don't replace them, the output current limiting
>> mechanism will go away. Even if there is an LV2000 present, it won't help
>> limit the output current for games that obviously overrun the limits of the
>> screen frequently such as Tempest, Star Wars, Major Havoc.
>>
>> Cutting the correct diode may make the problem dissappear revealing root
>> cause, but for the pennies per diode cost, I would certainly replace them
>> all.
>>
>>
>> William Boucher
>>
>> ----- Original Message -----
>> *From:* Mark Shostak <shostakmark@gmail.com>
>> *To:* vectorlist@vectorlist.org
>> *Sent:* Monday, December 21, 2009 7:19 PM
>> *Subject:* Re: VECTOR: Tempest foldover on right side
>>
>> I was going to ask the same question, but I'd say, if you have a
>> protection board, just cut the diodes out.
>>
>> -Mark
>>
>>
>> On Mon, Dec 21, 2009 at 6:06 PM, William Boucher <boucher@mnsi.net>
>> wrote:
>>
>>> I may be reaching a bit here, but does your monitor have the built-in
>>> protection circuitry (P327 board). D807 & D808 are known to create some
>>> bizarre behavior (folding, walling, linearity issues). Just replace them
>>> and all of the other similar diodes in the circuit with new 1N4148 type.
>>> The fact that it is walling on one side actually points to a specific diode
>>> in the circuit but I don't know which one without going back through all of
>>> the schematics. It would be better for the long term to just replace them
>>> all anyway and be done with it.
>>>
>>> I have a discussion page dedicated to this problem here:
>>> http://www.biltronix.com/wg6100_germs.html
>>>
>>>
>>> William Boucher
>>>
>>> ----- Original Message -----
>>> *From:* Kevin Moore <talon.k@gmail.com>
>>> *To:* vectorlist@vectorlist.org
>>> *Sent:* Monday, December 21, 2009 3:53 PM
>>> *Subject:* Re: VECTOR: Tempest foldover on right side
>>>
>>> One more interesting thing I just noticed. I increased the bounding box
>>> size about 1/2 more both sides for a total of 1 inch extra width. The fold
>>> over stays in the same place.
>>>
>>>
>>> On Mon, Dec 21, 2009 at 2:41 PM, Kevin Moore <talon.k@gmail.com> wrote:
>>>
>>>> Been busy, but I had a chance to make a quick video. I taped off the
>>>> region around the bounding box, so I would know where it was. It seems the
>>>> problem is about 1/2 inch outside that box on the right side.
>>>>
>>>> http://www.youtube.com/watch?v=2kMXHFCB5Zk
>>>>
>>>>
>>>>
>>>>
>>>> On Wed, Dec 16, 2009 at 7:31 AM, Andrew Welburn <andy@andysarcade.net>
>>>> wrote:
>>>>
>>>>> Don't always assume that a recently replaced part is 100% good, i
>>>>> would still replace the transistor with another one as a way to eliminate
>>>>> that possibility.. you just never know :-)
>>>>>
>>>>> Andrew Welburn
>>>>> www.andys-arcade.com
>>>>>
>>>>> ----- Original Message -----
>>>>> *From:* Kevin Moore <talon.k@gmail.com>
>>>>> *To:* vectorlist@vectorlist.org
>>>>> *Sent:* Wednesday, December 16, 2009 1:18 PM
>>>>> *Subject:* Re: VECTOR: Tempest foldover on right side
>>>>>
>>>>> Well the rom set is V2, good point on the boundary limit. I don't
>>>>> recall off hand, but when I get home tonight, I'll tape off the bounding box
>>>>> on the screen, and see. Wouldn't think it would be the Deflection trans, as
>>>>> I replaced all the Transistors with new when I re-capped, and did the LV
>>>>> upgrades. Don't think I have any V3 roms handy, but I'll check and see if
>>>>> that makes a difference.
>>>>>
>>>>> Thanks for the input, gives me a few things to check.
>>>>>
>>>>> Kevin
>>>>>
>>>>>
>>>>>
>>>>> On Wed, Dec 16, 2009 at 2:43 AM, Andrew Welburn <andy@andysarcade.net>
>>>>> wrote:
>>>>>
>>>>>> If its bothersome, you could try replacing the relevant chassis
>>>>>> deflection transistor, i've seen that before. Tempest unfortunately will
>>>>>> force the monitor to display vectors way, way outside the visibile screen
>>>>>> area, later romsets IIRR have a fix for this. Even if your monitor can
>>>>>> produce a full image, certain parts of the game will overdrive the
>>>>>> deflection such that the transistors will partially break-down, causing
>>>>>> other areas of the screen to show foldover like this.
>>>>>>
>>>>>> Its not clear if your boundary is inside or outside the real screen
>>>>>> limit anyway without a photo. you should set the test mode pattern up to
>>>>>> fill your screen then watch it in game, is the foldover inside this box?
>>>>>>
>>>>>> I'd replace the relevant chassis transistor first with a new one then
>>>>>> observe... Changing the romset to a later revision might also help, but this
>>>>>> is much more laborious, and is ignoring a weakness in your monitor anyway.
>>>>>>
>>>>>> Andrew Welburn
>>>>>> www.andys-arcade.com
>>>>>>
>>>>>> ----- Original Message -----
>>>>>> *From:* Kevin Moore <talon.k@gmail.com>
>>>>>> *To:* vectorlist@vectorlist.org
>>>>>> *Sent:* Tuesday, December 15, 2009 6:53 PM
>>>>>> *Subject:* VECTOR: Tempest foldover on right side
>>>>>>
>>>>>> I've noticed that Tempest has a slight foldover when the player
>>>>>> finishes a level, and the tube starts coming up. The left side the tube
>>>>>> lines go infinity for lack of a better word, but the right side seems to
>>>>>> fold over like hitting a wall, and it creates a straight line. Typically I
>>>>>> just adjust the picture so that the monitor shroud covers this. Is this
>>>>>> normal?
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Kevin
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
>
> André Huijts
> andre.huijts@upcmail.nl
>
>
>
>
>
>
>
> André Huijts
> andre.huijts@upcmail.nl
>
>
>
>
>
>

---------------------------------------------------------------------------
** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
** Please direct other questions, comments, or problems to chris@westnet.com
Received on Tue Dec 22 20:28:19 2009