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Dsavitsk/Beezar Torpedo Build Thread - Page 12

post #166 of 520
Quote:
Originally Posted by tomb View Post

I'm sorry about that tube socket.  The quality control is not so good sometimes.  They're wrapped in that wax paper stuff when I get them from China and I don't have time to check them all.  Every once in a great while, the ceramic gets molded badly and the tube pin holes get covered up, as you stated.  I would recommend the tip of a sharp knife such as an X-acto.  Ream the hole out by twirling the tip of the knife in the hole.  You have to be careful, though, if it's bad enough you could crack the entire top half of the socket.  If it's unsuitable, let me know and I'll send you another.
 

 


Cheers for the offer, but i think it will be ok. I can still plug a tube in, so I'll just leave as is.

 

post #167 of 520

 

Got everything soldered up, cleaned, pre turn on checks....
....switch her on and nice glow from tubes, no glow from LEDs :(
checked B+ and no voltage. turn it off and waited 20 minutes
came back, measured a few things, the high volt secondary of the power transformer is reading about a meg ohm resistance :( 
 
i'll desolder it and see if reflowing the terminations on the lead-outs fixes things, but i fear the worst for this tranny
 
post #168 of 520


 

Quote:
Originally Posted by DingoSmuggler View Post

 

Got everything soldered up, cleaned, pre turn on checks....
....switch her on and nice glow from tubes, no glow from LEDs :(
checked B+ and no voltage. turn it off and waited 20 minutes
came back, measured a few things, the high volt secondary of the power transformer is reading about a meg ohm resistance :( 
 
i'll desolder it and see if reflowing the terminations on the lead-outs fixes things, but i fear the worst for this tranny
 


I would be surprised if the tranny itself is damaged. They are pretty robust.

 

Measure the resistance between B+ and ground. The ground pad next to B+ is nice and handy. I would be surprised if you did not have a short.

 

Any pics? 

 

 

post #169 of 520
Quote:
Originally Posted by jdkJake View Post


 


I would be surprised if the tranny itself is damaged. They are pretty robust.

 

Measure the resistance between B+ and ground. The ground pad next to B+ is nice and handy. I would be surprised if you did not have a short.

 

Any pics? 

 

 

B+ to ground is 238k ohms, which seems to be right to me.

 

The secondary winding of the tranny at my guess should easily be under 1k ohm, 1meg ohm is definitely not right

 

i can't get pics tonight, will have to be tomorrow for those

 

 

i managed to reflow the lead-out connections for the high volt secondaries on the transformer without desoldering it, but this didn't help things. 
 

 

post #170 of 520
Quote:
Originally Posted by DingoSmuggler View Post

B+ to ground is 238k ohms, which seems to be right to me.

 

The secondary winding of the tranny at my guess should easily be under 1k ohm, 1meg ohm is definitely not right


True. I am measuring ~256 ohm across the high voltage secondary.

 

While hard to verify once solder into the board, you should be able to visually verify the wires coming out of the transformer and wrapping onto the pins.

post #171 of 520
I bet that there is a cold solder joint on the transformer itself. The wire they use to wind transformers is enamel covered, and if the manufacturer did not do a good enough job stripping the enamel, then the wire could be "soldered" to the pins, but not actually connected. If this is indeed what happened, repairing it will be a pain, but much less of a pain than trying to desolder the whole transformer -- ask me how I know that smily_headphones1.gif

So, take a look at the pins and see how good that solder connection is.

263
post #172 of 520
Quote:
Originally Posted by dsavitsk View Post

I bet that there is a cold solder joint on the transformer itself. The wire they use to wind transformers is enamel covered, and if the manufacturer did not do a good enough job stripping the enamel, then the wire could be "soldered" to the pins, but not actually connected. If this is indeed what happened, repairing it will be a pain, but much less of a pain than trying to desolder the whole transformer -- ask me how I know that smily_headphones1.gif
So, take a look at the pins and see how good that solder connection is.
 


I'm not going to ask bigsmile_face.gif

 

Yes this was one of my suspicions, and what i meant by "reflowing the lead-out wires" - but of all the joins on the transformer, these ones are the most obscured by other components, so I couldn't really see how bad the factory solder job was, or how much my reflowing of the joins was helping...

 

I had made an attempt at desoldering the transformer, and was left humbled. I think i will have better success removing the choke and C1 to give me some room to play, and try to fix the transformer in situ as you suggest.

 

post #173 of 520
Thread Starter 

I was waiting for Dsavitsk to respond - he is the authority, including/especially about the transformers.  It sounds like he has a good suggestion and we appreciate it if you are willing to work with it.  This is especially true because you're international and shipping won't be cheap or quick.  So, many thanks if you can try what Dsavitsk suggests.  However, don't keep trying long enough to get frustrated or even damage the transformer.  Of course, I will send you another one if it comes to that, but we'll need yours back to return to Edcor (I'll pay for shipping). smily_headphones1.gif

post #174 of 520
Quote:
Originally Posted by DingoSmuggler View Post

I had made an attempt at desoldering the transformer, and was left humbled.

The trick seem to be to add a ton of flux the joint and add some to your desoldering braid, then suck out the solder from each pin in turn. It is also a good idea to do the ones connected to traces first as then the excess weight will be on the pins that don't matter so much.

Also, I find it helpful to use a flat heat screw driver to pop each pin once all the solder that can be is removed.
Quote:
Originally Posted by tomb View Post

but we'll need yours back to return to Edcor (I'll pay for shipping). smily_headphones1.gif

Bah -- don't bother. I am sure Edcor will replace it, and if not, I'd rather eat the cost than force you to ship a bad part half way around the world.
post #175 of 520

OK, I've got a plan of action now.

Given the time zone differences, should hopefully provide an update while you're all happily sleeping wink_face.gif

post #176 of 520
Quote:
Originally Posted by dsavitsk View Post

Bah -- don't bother. I am sure Edcor will replace it, and if not, I'd rather eat the cost than force you to ship a bad part half way around the world.


I just needed to comment here. Classy. Seriously. Big points to all of you for being willing to get this right for him. 

 

post #177 of 520

You could try gently sanding the enameled wire with a file then solder a jumper down to the pin.

post #178 of 520

So i removed C1 and the choke which gave me room to work, so i decided to get desoldering braid in there so i could se how much winding wire was there. There was about 2 or 3 turns of winding wire wrapped on each post and it was definitely well tinned. Soldered them back up and it still reads open circuit.

 

trans1.jpg

post #179 of 520
Thread Starter 

I will do my best to get a transformer in the mail to you tomorrow.  I'm pretty sure I know who you are, but PM me your address, just in case. wink.gif

 

EDIT: Shipped yesterday.


Edited by tomb - 1/8/12 at 5:21am
post #180 of 520

Don't know what it is about my build that may be different, but I can't detect any hum.  Had it out to a mini meet last night and no one could hear any either.  Sounds great with Grados, and can drive a K340 even though it could use a bit more gain (for quiet recordings).  Thanks to Tom and Doug for making it easy to build, by providing us with a kit.

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