Transformer Dead?

[blxeu]

I put in a new capacitor at 12U & 13U, forgot to check the polarity and installed it backwards. It passed resistance checks but when I switched it on for the voltage test, it went from 75.2v to around 230v with a puff of smoke. Besides the capacitor, what other components possibly got fried? This is a Crack 1.1 no Speedball & resistances before voltage were basically the same except 22 & ground were 0.2 ohms. If more info is needed, please let me know. Thanks for the help!
Resistances:
1. 36Kohms
2. 36Kohms
3. 0.2 ohms
4. 3Mohms
5. 2.9Mohms
6. 0.2 ohms
7. 2.9Kohms
8. 0.1 ohms
9. 2.9Kohms
10. 0.1 ohms
12. 0.3 ohms
13. 2.5Mohms
14. 0.2 ohms
20. 0.3 ohms
22. 36 then jumps around in the Kohms
B3. 2.9Kohms
B6. 2.9Kohms
RCA both 98.3Kohms
Ground.  36 then jumps around in the Kohms

[Paul Birkeland]

I haven't ever seen a backwards capacitor destroy a power transformer.  If you put a fresh fuse in (it's likely blown) and turn the amp on with no tubes and without that capacitor installed, does the fuse blow?  How is the DC voltage at terminal 13 under these conditions?

[blxeu]

Hi Paul, thanks for the response. Glad to hear it's not fried beyond the capacitor.  I put in new fuse and removed the cap and tubes. The voltage reading at 13 is 243.2v and the fuse did not blow. I wasn't sure how long to turn it on for so I gave it 10 seconds before unplugging

[Paul Birkeland]

If you put a replacement cap in, you should be good to go.

[blxeu]

Something is still amiss. I replaced the cap and tightened the nut under 22 that was causing the resistance reading issue. The resistances were all good, same as above but with 22 and ground reading 0.2 ohms, but the voltage at terminal 1 reads 231.8v and terminal 2 read 152.6v

[Paul Birkeland]

How is the solder joint where the black wires meet at the headphone jack?  Nonsense voltages like that can often occur from a loose or poorly soldered ground wire.

[blxeu]

The solder joint on 12L was partially wicked away from when I removed the cap. I resoldered at 12L and the headphone jack. It is still showing 230v but it is now blowing the fuses

[Paul Birkeland]

Can you post some build photos?

[blxeu]

Let me know if you need pictures of a specific section

[Paul Birkeland]

Does the fuse blow if you power up the amp with no tubes?

The pot that you have is meant to be soldered to a PC board and the pins will break off if you solder wires to them.  There are small PC boards available on eBay that you can solder to the pot, then you can solder wires to holes in the board. 

[blxeu]

The fuse does not blow if I remove the tubes. I am not using the pcb with the pot because the one I got didn't fit the leads of the resistors and without them I couldn't get higher than 9 o'clock on the pot. I had made a mockup of the pot with foam and needles to wrap the wires and leads then slotted them over the pins of the pot. Do you think the pcb used in this project might be a better solution for this? https://www.diyaudio.com/community/threads/aegis-diy-tube-headphone-amplifier.399473/#post-7354944

[Paul Birkeland]

Next run the amp with just the 12AU7 and report the voltages on terminals 1-5.

[blxeu]

On 1 & 5 if I leave it for around 10 seconds, the voltage slowly climbs from 235 to 244 then plummets to 95.2 in about a second and holds steady.
2. 232.4v
3. 0v
4. 232.1v

[Paul Birkeland]

There's likely to be some component leads or trimmed wire ends touching something they shouldn't on the octal socket, which is causing your amp to draw too much current from the power supply during operation.  I have seen this kind of problem from something like a backwards 100uF capacitor on the rear 5 lug strip, but I don't see any obvious issues with your amp from the picture you provided.

With the amp off and the power supply discharged, hold your black meter probe on B2 and measure the resistance to the rest of the tube socket pins on the B socket and let me know what you find.

[blxeu]

B1. 22.11Kohms
B3. 752.6Kohm then slowly falls
B4. 22.08Kohms
B5. 0.1 ohms
B6. 554Kohms then slowly falls
B7. 2.6Mohms then falls
B8. 1.6Mohms then falls