Drip Sta-Level - First time power up blows the fuse

[Sparqee]

I just finished my Drip Sta-Level.  I powered it up  without any tubes installed.  The meter light came on but the power lamp did not (which seems strange since I wired them in series to the 6.3VAC "Lamp" terminal on the PCB).  I wasn't too concerned about the power lamp so I went ahead and powered off and then installed all the tubes.  As soon as I powered back on the fuse in the power receptacle blew. 

Any suggestions on what I should look for?  The PCB is quite spacious so there's not much chance of any bridged solder points.  I'm using the Sowter 9880 power transformer spec'd in the Drip BOM.

https://www.dropbox.com/s/yya7xvwr26oppvg/Gates%209880%20mains%20%28power%29%20transformer.pdf?dl=0
http://vid.firepixie.com/skitch/Sta-Level_Power_transformer_wiring-20150227-133232.jpg

 

[pucho812]

tripple check wiring.  check fuse value. is it the right value?

 

[CJ]

make sure you use a slo-blo as the heaters drag current until warm up,

 

[Sparqee]

I'm using the fuse value listed in the Drip BOM - 250V, 2A Slo-Blo (mouser part#576-0218002.HXP)

I'm using the Sowter 9880 power transformer.  I was told (by someone supposedly knowledgeable in tube circuits) that the unused leads of the secondary should be grounded to the chassis.  Looking at the build info of the Sta-Micro it says to isolate the unused power leads.  Which is correct?

I removed all the tubes other than the rectifier and the two 6v6 power tubes and with the unused transformer leads isolated the fuse does not blow.  I haven't yet tried putting in all the tubes with the transformer leads isolated but I thought I'd post my voltage readings first.
From the PCB power hook up terminals I get:
500v = 586v
5v = 5.9v
6.3v = 7.38v

From the two PCB test points I get:
300v test point = varies from 287 up to 379 but these values are very brief and quickly drop down to 0.47v
380v test point = 371 to 389 and as above the reading quickly drops to 0.47v

Is the voltage drop on the test points normal?  What about the slightly high AC voltages  at the PCB power hookup terminals?  Is that a problem or within tolerances?  Again I only have the rectifier and power tubes in right now.

Thanks for any advice. 

 

[dustbro]

I would just do a quick check to see if caps are installed properly, and then probe around to see if anything is shorting to ground that shouldn't be.

 

[CJ]

"the unused leads of the secondary should be grounded to the chassis"

no, don.t do that, put some heat shrink and tape around them, or tie them individually  to unused terminals on a tag board or terminal strip,