5E3 build

[Twin]

Yes, I spoke with Mark & he confirmed that the current OT schematic is correct & that the secondary does indeed ground to the frame of the OT(via feet attachment to chassis).

[soundguruman]

Are black and green coming out of one side of the OT case?
Lets see more pics.

[Enzo]

Don't just swap parts, find the problem.

resistors burn up because excess current is drawn through them.

If that resistor is burning up, then something about the downstream end of that resistor is too close to ground. Common reasons are the cap there is shorted. If you changed the cap already, make sure it is not backwards and that any excess wire lead is not going where it doesn't belong. Look under your part board to be sure.

Measure resistance to ground across that cap. That point is also wired to your power tube screens. That may be more convenient a place to measure for shorts to ground at pin 4. Unless you added some, there are no screen resistors, I don't see any. Since this is your build, look closely at the power tube sockets, to see if there is any wire from pin 4 of either tube touching ground, wired to ground, or touching something else, like pin 5.


If anything on the output transformer was shorted to ground, the resistor in question would not be what was burning.

[Twin]

No they don't just black & a yellow wire that shunts to the OT frame. On the the other side are the green, red & yellow wires that make up the primary side of the OT... You can see this in the pdf. Anyway reason why I pulled the green through the other grommet was because I wanted to get it over to the 6V6 without having to go over the other wires.

[soundguruman]

Please use an ohm meter, with the output tubes removed.
Confirm that there is a winding between green and yellow. Are you SURE??? (verify it, don't assume anything)
Lets see pictures of the transformer side...

USE the ohm meter. With tubes out, how many ohms between yellow and green??? Pin 3 to pin 3???

[Twin]

Will check resistance to ground at pin 4 first since not getting anything across the cap... Also recheck wiring to pins of 6V6's & get back... Thanks for your input Enzo!

[Twin]

OK, will do. More pics coming up...

[soundguruman]

Say: Ahhhhh.

[Enzo]

Please help an old man, and do not report "not getting anything" on a meter reading. Unless your meter is turned off, you always get SOMETHING. it reads zero ohm, that is not the same as "nothing." If it reads open, that too is not "no reading." Tell us what it says.

If you do not measure low resistance to ground from pin 4 or across the cap, then new or not, the cap could be bad, so just disconnect the hot end of the cap. See if that stops the resistor from cooking. A cap can measure OK on your hand meter (which uses only a volt or two) but still leak like a seive at anything over 20v, and so act like a dead short when 300v is applied.

[Twin]

266 ohms to ground at pin 4. Same readings across the cap. All the hookups like nice & clean(no grounds, stray wires, etc.)

[Twin]

more pics

ahhh...

[soundguruman]

OK, it looks alright at the tranny...
How many ohms at pin 3? to ground?

[Twin]

Pin 3 to pin 3 is 650 ohms. From either pin to ground measures 1ohm

[soundguruman]

OK there's your problem.
Pin 3 to ground should not be 1 ohm, that's whats burning.
Now disconnect green and yellow from both pin 3s.
Measure the wire only, to ground...
Measure the socket only pin 3 to ground.
Which one is 1 ohm to ground the socket or the wire?

[Twin]

What is?
When I took a measurement it was the same as a "no reading" like Enzo mentioned earlier.
I should also mention that when I got that reading there were no tubes in the sockets...