Power Transformer Test Issue [resolved]

[Jameson]

Hey guys. Started the Kaiju build and got to the first power transformer test. I’m seeing 119-120 VAC coming from the wall, but I’m only seeing 5.4VAC when I’m running the first test on page 33. I’ve reviewed the wiring a couple times, and I’ve tested continuity between each PT-9 lug and the terminal strips. I’m still not seeing 190 VAC. Here’s a picture of the PT. https://imgur.com/a/zwna7rr

 

[Paul Birkeland]

What AC voltage do you see between terminals 1 and 3 on the power transformer?

I would recommend doing the rest of the power transformer secondary tests as well.

-PB

 

[Jameson]

1 & 3: 119V
7 & 8: 5.3V
9 & 10: 6.55V
11 & 14: 6.56V
12 & 14: 6.57V

 

[Paul Birkeland]

If your meter happens to have selectable ranges and there's a 200V setting, you may need to go up one click on the dial to resolve the secondary Kaiju voltage.

If that isn't the case (I suspect it's not by the way), then we would like to get that power transformer back for inspection. 

 

[Jameson]

Yeah, it auto-ranges.

Should I plan to ship it to you guys? How should I prep it? Unsolder or trim the wires?

 

[Paul Birkeland]

I would desolder the wires. If you don't have the packing, transformers ship pretty well when they are wrapped tightly in tons of cardboard, then a little bubble wrap around the outside.  I'll let Eileen know about this today as well.

-PB

 

[Jameson]

Ok, got it. I just emailed Eileen and Doc as well. What’s the best address these days? I’ll try to get it in the mail this afternoon.

 

[Paul Birkeland]

Eileen will let you know.  She may have you send it to me for a tear-down, or she may want to send it back to our winder.

 

[Jameson]

Thanks, Paul. I’ll wait to hear from her.

Appreciate your help.

 

[Jameson]

New power transformer arrived today. Everything’s looking good! Thanks for the quick turnaround on this.

 

[newfangled]

I just started building the Kaiju this weekend. Unfortunately the power transformer secondary test on page 33 does not pass for me. I'm only getting 137V on pin 7/8; not 190V like I'm supposed to. I triple checked my wiring and solder connections. When unplugged off I'm getting the correct continuity readings.

I measure 120.8V from the wall therefore I used the "IF your voltage is GREATER than 115V AC and LESS than 130VAC" guide on page 30.

Actual VAC readings using a known working Fluke multimeter. (I used autorange and also tried 200V and 600V range just to make sure)

1/3 = 120.8V
4/6 = 120.8V
7/8 = 137.0V
9/10 = 6.5V
11/14 = 6.5V
12/13 = 6.5V

Is there any other trouble shooting I can do to narrow down if it's an issue with my wiring or could be the transformer?

 

[Paul Birkeland]

We will swap you out with a replacement.

-PB

 

[newfangled]

Replacement power supply received on 5/22/2023. Happy to report that fixed my issue. Even happier that less than I week later I completed the full build including half day of listening to the stock filament power supply. Lowest hum I could achieve was 6.8mV on both channels. I upgraded to the DC filament power supply. Didn't take another measurement but that knocked the hum down to inaudible levels from my listening chair.

 

[stuart.mclean]

My page 33 power transformer tests are failing as well, but much more dramatically.  0.031 to 0.036 V AC on pins 7 & 8 AND a blown fuse.  I've redone the wiring with the same results.  Passes first power test with 126.4 V but when I follow the instructions for wiring for that range and run the tests it returns a tiny voltage and the fuse blows.
Other test results:
1/3 .041
9/10 .029
11/14 0.26
12/13 0.26

The Kaiju kit was delivered April 3, 2023.

 

[Paul Birkeland]

Can you post some photos of your build so far?

 

[stuart.mclean]

Sure.  Here you go ...
Thanks

 

[Paul Birkeland]

The alligator clips you have on the power transformer terminals must not touch each other or the fuse will blow.

 

[stuart.mclean]

There was a small air gap, but to confirm I added a couple of wires to guarantee separation.  Unfortunately, same result (.034).  The DMM does show continuity across 7 an 8 so I assume the configuration is correct.
I'm using replacement fuses from Amazon (picture attached) if that may be an issue.

 

[Paul Birkeland]

Set your meter to read Ohms and (with no powder cord connected to the Kaiju and a fresh fuse installed), measure the DC resistance between the chassis and L on the IEC module, then the chassis and N on the IEC module, then let us know what those values are.

 

[stuart.mclean]

N = 0L
L = 0L
E = .9