Re: Black Widow Video Problem

Great suggestion Bill! I'll borrow a scope.. One of these days I'll be needing to buy one of those! -M

On Jan 31, 2012, at 12:48 PM, wboucher6@cogeco.ca wrote:

> If you have a scope, you could connect it in X-Y mode right to the 6012 DAC chip outputs (pin 18) and see if the image
> looks okay there. If yes, then try again after the B10/E10 switches just before the 1495's. The idea here to narrow
> down which section to focus on.
>
> Bill Boucher
>
>>
>>
>> Thanks Douglas! That's an excellent suggestion about A/B11's output. I'd forgotten that detail…
>>
>> I checked the resistors after I switched the chip/socket at C12 and looked at the voltages and chip activity with a
>> probe afterward and it looked fine. A/B11 also seems to be making the right noises (with the probe) but I do know
>> from experience that they can have strange effects as they die (had a Tempest once with a completely mirrored image
>> and it was the 1495. )
>>
>> The Y pot looks original. I'll meter it and see what I see. I get what appears to be y collapse or perhaps complete
>> fold over if I adjust the pot too far in either direction. Within the small range of pot movement where there's no
>> collapse, the Y image can be adjusted larger and smaller…if only a little bit. -M
>>
>>
>> On Jan 31, 2012, at 10:30 AM, Douglas Gauck wrote:
>>
>>> It does look like a Y axis problem. My question was how the X correction coming out of A/B11, going into your new
>>> main Y axis C12 could affect the output.
>>> Since it's socketed, you can pull out C12 and then check all the resistors around it in circuit - all that voltage
>>> in the area could have toasted one.
>>> You should be able to adjust Y size from limit to limit without collapse. Or do you mean shrink?
>>>
>>> Since there's been prior work done on the board (and the pots are often abused) is it Y size the correct 10K?
>>>
>>> -Douglas
>>>
>>>
>>> On Jan 31, 2012, at 12:37 PM, Malcolm Mackenzie wrote:
>>>
>>>> Thanks Douglas.
>>>>
>>>> The MC1495 at C12 has been socketed and replaced by me. That chip had been socketed before, but the contacts were
>> shorted under the socket. I replaced the socket and chip and that's how I got the video to come up. I haven't
>> replaced C11 as this problem appears to be in the Y channel, but I'll check into it. >>
>>>> As far as I understand the pincushion correction 1495s won't cause this problem. I'll try to piggyback a new one on
>> them to make sure. >>
>>>> One added note. I've noticed that the y-size pot has only a very narrow range of adjustment. Too small and I have
>> y collapse, too large, and y collapse. In the very middle of adjustment the pic stretches out to as it appears in the
>> pictures I posted. Don't know if this helps anyone pinpoint it. -Malcolm >>
>>>> --- On Tue, 1/31/12, Douglas Gauck <douglas@gauck.com> wrote:
>>>>
>>>> From: Douglas Gauck <douglas@gauck.com>
>>>> Subject: Re: VECTOR: Black Widow Video Problem
>>>> To: vectorlist@vectorlist.org
>>>> Date: Tuesday, January 31, 2012, 5:49 AM
>>>>
>>>> The caps are just sauce for the goose; I'd say the next likely cause is one of the MC1495Ls... at C12. I'm not up
>> to speed on how the others (A/B11 and A/B12) providing X and Y correction factor in. >>
>>>>
>>>> On Jan 30, 2012, at 11:19 PM, Maxstang wrote:
>>>>
>>>>> Thanks for the reply. TL082s have been checked and one replaced with no change. Voltages are good, but I
>> haven't replaced the caps yet. >> >
>>>>>
>>>>> On Jan 30, 2012, at 8:09 PM, Douglas Gauck wrote:
>>>>>
>>>>>> TL082 at D10 and/or D/E12?
>>>>>>
>>>>>> Also check the +/-15v and 6.8 volt supplies, and maybe give them new caps?
>>>>>>
>>>>>>
>>>>>> On Jan 30, 2012, at 8:42 PM, Malcolm MacKenzie wrote:
>>>>>>
>>>>>>> Hi all. I've been working on a dead BW board and now have it at least showing video, but it's still distorted.
>> AVG chip and socket, and vector RAM and socket are good. Anybody seen this before? It almost looks like vertical
>> fold over and the image does expand and contract along the y axis. Self test video is similarly distorted but I don't
>> get any reported errors other than pokey problems. Any input is appreciated. -Malcolm >> >>>
>>>>>>> Photos are here:
>>>>>>>
>>>>>>> http://i122.photobucket.com/albums/o263/maxstang289/IMG_2612.jpg
>>>>>>>
>>>>>>> http://i122.photobucket.com/albums/o263/maxstang289/IMG_2611.jpg
>>>>>> ---------------------------------------------------------------------------
>>>>>> ** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
>>>>>> ** Please direct other questions, comments, or problems to chris@westnet.com
>>>>>
>>>>> ---------------------------------------------------------------------------
>>>>> ** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
>>>>> ** Please direct other questions, comments, or problems to chris@westnet.com
>>>>
>>>> ---------------------------------------------------------------------------
>>>> ** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
>>>> ** Please direct other questions, comments, or problems to chris@westnet.com
>>>
>>
>>
> ---------------------------------------------------------------------------
> ** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
> ** Please direct other questions, comments, or problems to chris@westnet.com

---------------------------------------------------------------------------
** 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 Jan 31 16:17:35 2012