G07 testing - What did I blow up?

[8BitMonk]

So I went to test the B+ on a G07 chassis I'm working on and in a totally boneheaded move accidentally clipped the ground onto the other end of the large white ceramic resistor rather than onto the metal frame and shorted it.   

Does anyone know exactly what this would take out? I'd like to replace only the damaged component if possible but not sure exactly which it would be or how to check. The picture is scrambled and the B+ reads way low now, 50v. Swapped in another G07 chassis and it works fine so I know the damage was limited to the chassis.

Appreciate any help or advice.

[ed12]

if your reading a b+ at all? means u shorted the requlator transistor,and or it's drives.
do u have the schmeatic ?

ed

[8BitMonk]

Schematics here: http://www.arcade-museum.com/manuals-monitors/Electrohome%20G07%2013in%20and%2019in%20Color%20Raster.pdf

So that's the regulator transistor that is on the side of frame right on the other side of the R902 ceramic resistor in the image below right?

[ed12]

yes sir
and if u follow the schematic u will note a driver transistor. or 2
btw that req,depends on the suffix is ehiter 1 of 2 styles
a 3 pin
or a 2 pin
be careful

ed

[8BitMonk]

I don't know how to read schematics, where am I looking? Hoping I can just replace the voltage regulator, that seems to be an available part. Thanks for the help!

Edit: Ok, I just pulled up a little tutorial on reading schematics so I could better understand the symbology. I see the regulator on the left on the schematic (i have the 19" version) but not sure of the driver transistor you say it leads to or how that'd effect my repair.

[behrmr]

Looking at the schematic there are 2 transistors in that circuit X901 (2SC2688) and X902 (2SC1890) so probably test everything in the 900's.

[8BitMonk]

Looking at the schematic there are 2 transistors in that circuit X901 (2SC2688) and X902 (2SC1890) so probably test everything in the 900's.

Ok, that makes sense, I see the 901/902 transistors on the schematic. Do I need to check values or just continuity?

[behrmr]

I would check to see if those transistors are shorted.  Use diode test (beep) for each leg to the other two.  If shorted then they are bad.  Not sure what the values of each of these specific NPN transistors are supposed to be. 

I didn't read all of the way back but also check your fuses F901 and F902.  If F901 is blown immediate discharge the B+ filter cap or you'll be in for a not so nice surprise.  I just short the + and - leads with a large screwdriver.

[ed12]

diode chk the pair of drivers
what is the requlator # ?
as i said they came in 2 flavours

ed