Kaiju 300B build - High Voltage Power Supply Test output incorrect [Resolved]

[cjohannsen]

Howdy!  I'm assembling my Kaiju, and I've reached the High Voltage Power Supply Test section.

All assembly and testing up to this point has been successful.

Multimeter black wire it clipped to 1U.

When I measure the voltages, I expected:
10U - 250VDC+/-20%
14U - 490VDC+/-20%
15U - 250VDC+/-20%

When I power on the unit with the multimeter across any of these points there is initially no voltage, but it begins to climb at ~0.01VDC per second.  When power is disconnected it begins to drain back to zero.

I've attached pictures of the unit as measured.  I'd love some help diagnosing the issue.  Any ideas?

Let me know if you'd like other images and I'll grab them and upload them.

Thanks!
Cory

[oguinn]

53 and 65 don’t look soldered or attached well. Unsure if that’s the cause (or if they’re even meant to be soldered at this stage).

[Deke609]

Ditto for 14U and 13L.

[cjohannsen]

From what I can tell 53U and 65U are not meant to be soldered yet.

14U is definitely not supposed to be, that is mentioned in the instructions.

13L is soldered, but doesn't look it in the pictures.  I'm going to reflow it just in case it's a bad solder joint.

[Deke609]

14U is definitely not supposed to be

Maybe wrap the lead around the terminal and crimp it - from the photos it doesn't look firmly attached.

[Paul Birkeland]

You can use a bit more solder on most of those joints.  For the lower holes on a terminal strip, it's reasonable to fill them with solder.

[cjohannsen]

I went back through all the steps for the power supply, resoldering every joint as I went to ensure they are good.

The problem is still the same.

I took a fresh set of images to show how it looks at the moment, which I am attaching.

I can't find anything that I have obviously done wrong (no missed steps or incorrect wiring).  I must have made an error somewhere, but I can't see it.

Also: I didn't mention it explictly, so here are the results of the previous tests:
Powerline voltage test: 119.7 VAC
Power transformer secondary test:
  189.6 VAC (PT-9 terminal 7 to PT-9 terminal 8 )
  6.3 VAC (PT-9 terminal 10 to PT-9 terminal 9)
  6.3 VAC (PT-9 terminal 14 to PT-9 terminal 11)
  6.3 VAC (PT-9 terminal 13 to PT-9 terminal 12)
300B Glow Test: success for both tubes
5670 Glow Test: success for both tubes
Ground Buss Check:
 0 Ohm measures at all test point (1,2,3, 13, 18, 24, 25, 26, 33, 38, 45)

That indicates to me that I made a mistake somewhere in the High Voltage Power Supply assembly.

[Deke609]

That's a head scratcher. Are you sure you're measuring DC voltage and not AC voltage? Measurements in the tens of millivolts could just be AC ripple.


cheers, Derek

[Deke609]

Andif that's not it, maybe double check the white wiring of the first two caps after the power transformer. In the circled connection in the attached pic it looks like the insulated portion of the wire extends into the joint. Can't see the connection to the other cap, but maybe check that too.

[edit: forgot to attach pic]

cheers, Derek

[Paul Birkeland]

I agree with Derek, try using your meter to measure the voltage of a 9V battery.

[cjohannsen]

I tested the meter with a fresh 9V and all the ranges work properly.

[cjohannsen]

Success!

Derek was right, the white wire at 41L was not cleanly seated.

10U: 263 VDC
14U: 519 VDC
15U: 277 VDC

Thanks everyone!

[oguinn]

Ol' eagle eye Derek