MSefi.com read only forum (Jan.15,2018)

Hello everyone!!

I just started building my MS II using a V3 board and i've run into a little hickup

I was soldering Q23 into position and although the legs didn't seem to be shorted, i measured resistance across de legs before snipping them off and i found that while resistance was infinite across two of them, across the other two there was a short.
I started cursing and swearing, got myself some desoldering braid and took the f****r out.
It now turns out that measuring resistance across the board terminals, without Q23 installed i still get a short between two of them. The board is fully clean of solder (or so it seems) and i've hit a wall trying to figure this out.
Are these two shorted by default?? how did i screw this up? is there any way to fix it?

Here's a piccie to illustrate.



Thanks a lot in advance for your help.

Cheers!

The pins 2 and 3 on Q23 are connected to the R56 trim pot. Depending on the position you've set R56 to, it can very well almost short these pins to ground.

oh. brilliant... Should have checked the schematics before posting...

Will give it a shot tonigh varying the position of the pot to see whether resistance changes and/or matches the one directly across the pot.

Incidentally, considering that the transistor has been soldered, desoldered, grabbed with pliers(not squashed, but grabbed) etc, should i recycle it or just get a new one?

Thanks for your help!

I tried turning the screw on the pot and voila! no more short.

Thank you VERY much. Still waiting on advice on whether to replace the transistor!

Kaboom wrote:I tried turning the screw on the pot and voila! no more short.

Thank you VERY much. Still waiting on advice on whether to replace the transistor!

Most DVMs have transistor tester.