Re: New Vector Monitor Project: Microprocessor, etc...

On Fri, 05 Nov 1999 00:53:51 -0600, Rodger Boots <rlboots@cedar-rapids.net>
wrote:

>James Nelson wrote:
>
>> I'm looking carefully at the National LM3886 Power OP AMP for direct yoke
>> drive, and it doesn't cost the $100+ each like some of the other <choke>
>> cool ones do, and it has all kinds of protection circuitry, and Class AB
>> circuitry.
>>
>> Rodger is going to look at the LM3886 to see what complaints he might have
>> with the device, and I might throw up a proposed 1st order schematic for
>> that circuit soon.
>
>Well, I've looked at it and have some serious questions if it has the raw balls
>needed for a color vector monitor. B&W, maybe, but I think it's going to keep
>shutting down running color, even with massive cooling. Especially on games
>that overscan the monitor.
>
>Yeah, shutting down will protect the IC, but how many times can you collapse the
>sweep on a game before you burn a big cross in the middle of the CRT. We're not
>talking losing one half of a screen here, we're talking collapsing into a line.
>Or worse yet, a dot if both channels dump at the same time. The spot killer had
>better be damn fast.
>
>I hate to keep raining on this parade so would someone please tell me I'm full
>of it (and be ready and able to prove it!) already?

No way Rodger your the man!

These are all the same issues that came up that last time we decided to redesign
a vector monitor (and the time before that).

It's never been hard in theory, it all gets down to costs.

I had a question about a previous statement you made:

   "Look at the specs for a BU806 sometime. A real shame there isn't a PNP
equivalent."

If the BU806 is a nice transistor then:

#1 Can it be used "as is" in a G-08. I have no specs on that part. How's its
gain, will I have to beef up the heatsinks on the pre-drivers to compensate?

#2 Can it be used in the redesign using the same "pseudo PNP" configuration the
G-08 uses on it's outputs?

-Zonn
Received on Fri Nov 5 02:00:37 1999