5E5A bown PT need help with cause

[mac0611]

I fried the PT on my tweed pro last night on initial startup after a total rebuild. My colorblind ass soldered the red centertap of the OT to pin 3 on the power tube socket and the brown plate lead to pin 4. Would this be the cause to the meltdown? After checking the blown PT there is a short from the heater windings to the high tension windings, and it stinks! I had a 3 amp slo blo in there ad that didn't help. I should have used a limiter, but I was rushing. I need to verify this before I blow another 150 dollar PT. Thanks.

[sluckey]

soldered the red centertap of the OT to pin 3 on the power tube socket and the brown plate lead to pin 4. Would this be the cause to the meltdown?

Not likely.

After checking the blown PT there is a short from the heater windings to the high tension windings, and it stinks!

That's highly likely if the short existed before you powered it up.

Do you have the short with all secondary leads disconnected?

[eleventeen]

One thing I do when trying out stuff for the first time or if I am trying something somewhat harebrained is to "fabricate" a fuse.

Fuses actually cost money these days. So, while I support the idea of the lamp limiter on "first power up" of something you have no idea of whether it works or flames or not, another thing you can do, once you are past that point OR in place of that step is to "make" a fuse by taking a short length of stranded wire and stripping 1"-2" of insulation. Now take one of the tiny strands and solder it in place somewhere as your fuse. One place is right across the fuseholder, but you can do this almost anywhere. Obviously you are not going to know the "rating" of your fuse although you could actually micrometer-measure the gauge of the individual strand and look up its ampacity. Fine, but that doesn't really tell you where it will fuse and melt and open up. And you are not taking a fat strand of #8 stranded wire, you are taking a single very thin strand of 20-22 ga hookup wire, one of 7 or 9 total strands, the idea being that if you get a 3-4-5 amp surge through that link, it will almost certainly blow. Cost = zero. Obviously, keep your fingers away from the uninsulated wire. If you are trying to simulate a 250 ma B+ fuse, you might use some imported shielded wire and use one of the teensy weensy wires from the braided shield.

Hey, it beats blowing 5 fuses which cost several bucks, never mind the time to replenish your stock.

[mac0611]

soldered the red centertap of the OT to pin 3 on the power tube socket and the brown plate lead to pin 4. Would this be the cause to the meltdown?

Not likely.

After checking the blown PT there is a short from the heater windings to the high tension windings, and it stinks!

That's highly likely if the short existed before you powered it up.

Do you have the short with all secondary leads disconnected?

It has zero ohms between the ht and heater center taps. all leads disconnected. It has to either be the rectifier tube or somehere else down the line. This is a known good PT that was running fine before the rebuild. I fired it up with no tubes except the rectifier. I had a 100k 3w resistor between pin 8 and the B+ going to the standby switch to slowly bring up the PS caps. They have been sitting for 3 yrs.