Re: Vectorbeam monitor issues

One reason I hesitated on changing the 7409 to a 7406 is it looks like a
factory mod and I wasn't sure if other parts of the circuit had also been
modified to accommodate the 7409. The reason I think it's a factory mod is
because Bill Boucher's NIB Space War has a monitor identical to mine, and
his also has the mod as can be seen
here<http://www.biltronix.com/images/space_war/2008_11_22/vsw_2008_11_22_05.jpg>.
I'm hoping someone here can help me understand this.

I will swap it with a 7406, but should I leave the diodes in place?

I forgot to mention in my original message that I verified the .5 amp fuse
in the power supply is good.

I will check C10, thanks for the suggestion.

Carlos

On Tue, Mar 26, 2013 at 10:06 AM, Rodger Boots <rlboots2@gmail.com> wrote:

> 7409 is wrong part, change it to 7406.
>
>
>
> On Tue, Mar 26, 2013 at 7:14 AM, Carlos Rubio <csrubio@gmail.com> wrote:
>
>> Hello, I'm working on a Vectorbeam monitor on which I've replaced about
>> 90% of the components. This monitor is the "discrete" version with the HV
>> components on the monitor PCB. It also uses the older part numbers.
>>
>> Currently the screen is blank, but I'm not sure if it's a problem with
>> the intensity circuit or a legitimate spot killing. Jumpering Q2 (labled
>> Q24 on my board) causes the picture to appear and reveals that the top half
>> of the image is missing. All transistors have been replaced.
>>
>> I should also mention that this monitor has a 7409 at IC7 (labeled U6 on
>> my board) instead of the 7406 referenced in every document and schematic
>> that I've seen. There are diodes between pins 1 and 8 and 3 and 8 as seen
>> here<https://lh3.googleusercontent.com/-aQ9D82rvVr4/UVGOweZsPXI/AAAAAAAAKBk/E1w6AkFky-g/s895/IMG_0007.JPG>.
>> I've replaced the 7409 and the diodes with new ones, exactly as they were.
>> The symptoms were the same before and after.
>>
>> I'd appreciate any insights in understanding if one problem is related to
>> the other, and how to narrow down the fault(s). Thanks,
>>
>> Carlos
>>
>
>

---------------------------------------------------------------------------
** 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 Mar 26 10:28:43 2013