Blast City – 2931 FUBAR

Joey’s analysis of my 2931

Well turns out mate that it’s the tripler inside the flyback that has failed, it had damaged an SMD IC in the regulation section plus the 5 pin regulator and zener protection diode, H-Drive transistors and vertical IC, this is supposed to shut the chassis down but as the IC was shorted it kept driving.
I replaced the blown bits and within a few seconds it blew everything again, so I took your flyback out and put it in another old one of these chassis that’s in real bad shape I only use for testing flybacks, anyway within seconds it shutdown like it was supposed to.

I don’t have a good flyback spare and the after market ones just aren’t any good, also the SMD IC that blew on yours isn’t readily available I only found them parts on an old parts chassis, so many hours later ( over 5 today ) still no working chassis !! damn frustrating these things, every time I work on one it only cements why I don’t do the MS293xx series anymore.

I do have a nice fully working spare that I wasn’t planning on parting with if you want to go that way.

So essentially I FUBAR’d my 2931 – note to self, never turn on a chassis ever again without the H/V connectors from the yoke connected.

I received the working spare chassis on Thursday and to say I was careful when putting on the chassis is an understatement!

Turned her on… and BEAUTY! SHE WORKS!!!

After the excitement of seeing it alive again, reality came back down when I couldn’t stretch the image wide enough

See how I was on HSIZE MAX but I’m still missing a big chunk on the right and a little on the left?

On a good note, the video clearly shows that the wavy corners are no longer present. So it must’ve been the chassis all along and not the yoke!

I guess as a bonus, I have an impregnated yoke. There’s still some buzz that occurs when you start up the cab, but seems to disappear after a while.

So after searching for information all over the place, I couldn’t for the life of me figure out why I couldn’t get the image to expand. I tried the H-Drive pot (didn’t change it too much). I tried the “extension” menu with additional settings (hold down a button for 3 seconds) but there was no setting. I know on the 2930 there was a pot HSL for horizontal size limit, but I couldn’t find anything for this chassis.

When in doubt, what do you do? RTFM

. I found the service manual of the 2931 – low and behold there’s commentary there talking about entering a “factory adjustment mode” which is different to the “extension” mode