[Coco] Cross Post from the Facebook Page about the RGB2VGA Board

[Zippster]

If you were applying it a little at a time I guess I could see that,
but submerging boards in an inch or two of iso works perfectly for me.
I do go through a lot, but it’s cheap.

I use a high rosin flux leaded solder (3.3% flux) as well as plenty of
Amtech 4300 (syringes) when called for, so the boards are well fluxed when finished.  :)

I’m doing tens or dozens of boards at a time, so a plastic bin and a serious bath is my method.

- Ed


> On Jul 10, 2015, at 10:11 PM, John B <trymyz at gmail.com> wrote:
> 
> Ed,
> 
> I have some flux and electronics cleaner I use.  Alcohol works good but
> takes way to much to clean rosin flux.  Even my flux cleaner takes some
> effort.  Its the cheap stuff from the local electronics store.  I should
> probably invest in the more expensive flux cleaner.
> 
> On Fri, Jul 10, 2015 at 11:05 PM, Zippster <zippster278 at gmail.com> wrote:
> 
>> I’m following this thread with interest, as I’m going to be finishing up
>> theRGB2VGA boards that people had ordered from Kip
>> to get that project successfully completed.
>> 
>> It is true that different monitors are more or less tolerant to certain
>> differences in signals, that could explain
>> some of what is being seen here.
>> 
>> Regarding cleaning boards, 91% isopropyl alcohol works wonderfully.  What
>> I do is submerge the boards in the iso in a small
>> tupperware type container, soak for 10 minutes or so, brush them with a
>> toothbrush while in the bath, then rinse with fresh iso and air dry.
>> Be sure to use the 91%, the lower concentrations have too much water in
>> them.  It’s available at drug stores, walmart, etc.
>> 
>> - Ed
>> 
>> 
>>> On Jul 10, 2015, at 9:39 PM, Steve Batson <steve at batsonphotography.com>
>> wrote:
>>> 
>>> John,
>>> 
>>> Have you changed the resistors yet, or are you using the resistors
>> recommended for the design? I was seeing jitter, where the entire screen
>> would jerk and occasional waves going through it mostly noticeable on the
>> edges. Also, it didn't seem consistent, sometimes it was worse than others.
>> Based on what Roger had found, it sounded like there were a number of
>> issues being caused by the original resistor values. Voltage Levels were
>> not what they should be. Also there was issues with the HSYNC and VSYNC
>> again caused by original resistor values. Luis and posted on the FB page a
>> response to one of my questions that some CoCo's are noisier than others
>> and this may very well be true, but I'd guess symptoms could be worse on
>> some systems then others which could be the combination of the CoCo and
>> Monitor. From discussions with Roger about this and how he fixed it, I'm
>> going to go out on a limb here and suggest that with his suggested resistor
>> values, the video will most likely be crisp, clean and jitter free on most
>> any CoCo and VGA monitor unless they have problems of their own.
>>> 
>>> It was a bit of a pain in the butt pulling a bunch of resistors out and
>> replacing them with Rogers suggested values, but I'd highly recommend it if
>> you haven't done so already. It was totally worth it! If you have already
>> replaced the resistors with the new values and are still having issues, I'd
>> suggest the following:
>>> 
>>> 1) Inspect your board and make sure you have no possible shorts. Clean
>> it real good with alcohol or other good electronic board cleaner and
>> thoroughly dry.
>>> 2) Check all the cables including power going to the board and make sure
>> all is well
>>> 3) Make sure the ribbon cable isn't right next to a transformer
>> including the CoCo power power supply (thought I am not having issues even
>> if set the board right on top of the CoCo above the transformer). This
>> probably is NOT an issue.
>>> 4) Remove wire I mentioned that was a ground fix.
>>> 
>>> Anyway, let me know if you have changed the resistors yet or not. I'm
>> very curious to see where you are at.
>>> 
>>> 
>> 
>> 
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>> 
> 
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