Voltage Check Failure

tayjj1987

New member
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:

TerminalVoltage (DC)
+275vDC on the Power Supply Board211V
+6.3vDC on the Power Supply Board1.7V
IA on the A side C4S Board209V
IA on the B side C4S Board209V
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!
 
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.
 
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.
 
tayjj1987 said:
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.

 
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