Removing PVA from a CRT

[Paul Koning]

> On Nov 19, 2018, at 4:01 PM, Alan Perry via cctech <cctech at classiccmp.org> wrote:
> 
> 
> 
> On 11/19/18 12:18 PM, Warner Losh wrote:
>> 
>> 
>> ...
>> 
>> I have a VR201 that's like this myself, and I've been too scared to try to fix it. Instead, I've tried bodging together various hacks to try to get the signal into a modern composite to VGA converter...

I've been thinking about that.  There are assorted converters around for sale but the trick seems to be the sync on green (rather than separate sync which is common in various other flavors).

Is there a worked-out design for this anywhere?

>>    Finally, a VR201 specific question. I booted the Rainbow over the
>>    weekend and, looking through broken-down PVA, I could see the
>>    Rainbow has booted and I could enter DOS commands. I could also
>>    see white retrace lines. What is the likely cause of that on a
>>    35-year-old CRT?
>> 
>> 
>> Pics?
> 
> Here is an attempt to use Facebook for image hosting here. If it doesn't work, I will put the image up on a real image hosting site.
> 
> https://scontent-sea1-1.xx.fbcdn.net/v/t1.0-9/46508514_10156808244977208_2306314600917762048_n.jpg?_nc_cat=105&_nc_ht=scontent-sea1-1.xx&oh=81c3e1ded7cb1eb6b9d1200a604d9889&oe=5C7778F1
> 
> alan

It looks like you turned the intensity up so far that the retrace didn't get blanked fully.  Not much choice about that given the bad screen, I suppose.

	paul