Voltage Check Failure

[tayjj1987]

I recently completed my Mainline where I passed the resistance checks but failed the voltage checks. I have reflowed every solder joint on the board twice and the voltage checks are still the same.

Specifically, I will have the following voltages:

Terminal	Voltage (DC)
+275vDC on the Power Supply Board	211V
+6.3vDC on the Power Supply Board	1.7V
IA on the A side C4S Board	209V
IA on the B side C4S Board	209V
Breg Regulator Board (both sides)	158V
-reg Regulator Board (both sides)	-57V
Kreg Regulator Board (both sides)	46V on one side and 54.8V on the other side

Curiously, I will read 270V at +275vDC on the Power Supply Board when I first turn on the power but the voltage will drop almost immediately and stabilise around 211V.

I tried experimenting with how the voltage measurements was done. Instead of clipping the black negative lead of the volt-ohm meter to the ground buss at terminal 7, I tried clipping the black negative to the E terminal of the IEC power inlet. When I do so, all the voltages are within 10% range except for the voltage at +6.3vDC on the Power Supply Board where I will have a measurement of 58V.

I am at a lost what does of all this information meant. Any help will much appreciated!

[Paul Birkeland]

How was the test on page 52 where you test that power supply board?  If it passed there, but now you see 1.7V on the 6.3V output, then there's a short between pins 4 and 5 on one of the 6C45P sockets most likely. 

Seeing -57V on a -reg on a regulator board tells me you have a missing or loose ground wire.  The voltages changing dramatically when you use the earth terminal instead of terminal 7 also points to this. 

A reading of 58V on the 6.3V pad on the power supply board is OK.  What DC voltage do you get between the + and - pads on the 6.3V output of the power supply board?

I would be nearly certain by what you've posted that you have some loose connections that need more heat with the soldering iron.

[tayjj1987]

Thanks for the help, Paul.

I did not encounter any issues when performing the tests on page 52. Thus I continued building the Mainline and only encountered voltage issues at the end of the build.

The DC voltage between the + and - pads on the 6.3V output of the power supply board is +1.7V and -4.7V respectively.

I wasn't expecting any more loose connections because I was checking for that when I reflowed the solder joints. I guess I may have missed something. I will look into the areas you mentioned over the weekend.

[Paul Birkeland]

The DC voltage between the + and - pads on the 6.3V output of the power supply board is +1.7V and -4.7V respectively.

The voltage between the + and - pads would mean putting the black probe on the - pad and the red probe on the + pad.  From what I can gather from your measurements, you seem to have 6.3V coming out of there.