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Main => Monitor/Video Forum => Topic started by: benll64 on October 01, 2013, 02:23:21 pm

Title: Sharp Image SI-727R-DS Sync Problems
Post by: benll64 on October 01, 2013, 02:23:21 pm

OK, this is driving me crazy. This is a dual-res monitor; it has a little connector on the chassis where you choose either 15KHz or 25KHz (it's set to 15, where I want it).

The chassis was just fully repaired and guaranteed to work by the repair person. It is being driven by the latest ArcadeVGA card from Ultimarc, and is connected through the Ultimarc video amplifier.

Here's a picture of what should be the PC's BIOS setup screen:

(https://db.tt/WfBpfYmA)

And here's a short video clip of the same thing (sorry, it's a MOV file):

https://db.tt/GhSj2lDD (https://db.tt/GhSj2lDD)

I've messed with every potentiometer I can find, which does various things to the picture - but nothing that results in a stable/correct image.

Anyone?

Title: Re: Sharp Image SI-727R-DS Sync Problems
Post by: BC_Jeffro on October 12, 2013, 11:39:27 pm

to me it dose look like a sync problem
what happens when you switch it to med rez?

Title: Re: Sharp Image SI-727R-DS Sync Problems
Post by: benll64 on October 13, 2013, 05:59:30 am

After much trial and error, I solved this one.

Turns out there were two problems:

2) The sync wire connection was mislabeled on the chassis PCB (!) The "S" was next to pin #6 on the sync connector, and out of desperation I switched it over to pin #5, and, voila - a picture. Weird...

1) The color drives were off. Set all 3 to their near-highest setting and I got the proper solid milky-white color on the screen.

All works now. Maybe this will help someone else trying to use one of these SI monitors.

Title: Re: Sharp Image SI-727R-DS Sync Problems
Post by: Ken Layton on August 16, 2014, 09:54:51 pm

I'm working on one of these monitors right now. Yes, I can also confirm that the sync pin is mis-labeled on the chassis. Where you'd normally expect the sync signal to go to the very last pin (pin 6), that pin is actually not connected to anything on the foil side of the board. It's a 'dead' trace!

The sync (composite negative) actually needs to be connected to pin 5 on the video/sync input header connector. See the attached picture for details.

Title: Re: Sharp Image SI-727R-DS Sync Problems
Post by: bobbyb13 on June 26, 2021, 05:47:08 am

I know this is a really old thread, but holy crap...

THANK YOU Ken for your reply to this- on both critical points of live pin and sync type.

I am starting my foray into working on real monitors on this exact chassis and failed first try this evening to get a picture with my brandy new TPG.

Can't wait to shift pins on my harness and try again tomorrow.