K7000A Voltage Regulator testing

[slammin]

Hi everyone, I suspect that my voltage regulator is bad (STR 30130) and I tested all the leads to compare to the readings in the Monitor FAQ posted by menace.  My readings are not the same, but I'm unsure if that
means it's bad.  I removed it from the board before testing.  Thanks for any info.

in the monitor FAQ:

STR30130
1 to 2,3,4,5   open
2 to 1,2,3,5   open
2 to 4            1667
3 to 1,5         open
3 to 2              587
3 to 4            595
4 to 1,3,5      open
4 to 2            1065
5 to all           open

Mine: multimeter set to diode

1 to 2,3,4,5   open
2 to 1 =2.862v
2 to 3,5 =open
2 to 4 =1.9v
3 to 1 =2.92v
3 to 2 =.609v
3 to 4 =.631v
3 to 5 =open
4 to 1= 2.871v
4 to 2 =.934v
4 to 3,5 =open
5 to all =open

[slammin]

Ok, so I am going to answer my own question.  The voltage regulator is perfectly fine.  I found the issue was with a couple of the VR pads, they were lifted and separated from the circuit.  Interestingly, they showed continuity in circuit, but not stable enough for operation I suppose.  Anyway, reinstalled the VR with bridged connections to the circuit and the monitor works fine now.


I will also post the original problem that was repaired in the event that someone has a similar issue.  I always hate finding posts that leave you hanging, especially if you have similar issues.


Problem: Wells Gardner k7191 (Zenith k7000A series) was not filling the screen horizontally. 

The first thing I did was test the B+ on the large resistor hanging off the side (R301) I had 154VDC on the unregulated side (closest to the tube) and around 100VDC on the regulated/ B+ side.  According to Randy Fromm's flow chart it was C57 or the VR.  I pulled the VR to check, which is when I noticed a couple of pads were lifted and separated, but since I had tested continuity previously, I wasn't sure that was the problem.

I tested the VR and posted the results here.  I decided to try reinstalling it and bridge the bad connections in hopes that the VR was still good.  Voila, the game filled the screen, problem fixed.

So, if anyone has an issue with horizontal width not filling the screen, with low B+, maybe it's a similar issue to mine. Hopefully this post can help someone in the future.