docz wrote:Ok, just a quick question before I start rewiring, which of the leads go to 110V and 0V?
Blue->110V
Brown->fuse->switch->0V
or the other way around?
It doesn't matter. The transformer is just a length of wire wrapped around a hunk of metal. It is just a labeling convention to indicate one end of the coil from the other.
Your PT has 4 terminals, two marked 110 and two marked 0. In Norway, you have 230V line supply so the transformer needs to be properly configured for it. The two sets of terminals allow for this. Your picture show swires to the outer lugs for 110 and 0. This is the correct wiring. There also needs to be a jumper between the two inner lugs 110 and 0. This combines the two windings, in phase, and makes it into one long winding. Without the jumper, you will not see voltage. I can't see that side of the transformer. If you have the jumper in place, then it is likely that your PT is shorted. I see solder on the inner lugs (terminals), so I think the jumper is there.
And when I measured the caps using that method, with meter set to DC voltage, I did not get a reading.
See above. Either the juimper is missing or there is some other problem.
When I test the two leads on the speaker transformer image I get zero resistance.
There is a primary winding and a secondary winding. Primary goes to the power tube (EL84) and ground. Secondary goes to the speaker. It is likely the primary has very low resistance and your meter can't "see" the difference between 1 and less than one on the primary. Also, to get a reading on the primary, you will need to lift the connection from ground. There is a difference between 0 and open. If you are seeing 0, there is continuity and that's good. If you are seeing an open load (usually displayed as "OL" on the meter), there is no continuity and the transformer is blown (useless).
On the secondary (speaker) side, you should see a reading. It could be as low as 50 ohms, and probably not anywhere near 500 ohms. Transformers vary, so I don't know what you should see exactly. If you see OL, then the transformer is bad. If you see very low ohms (like 10 or 20) there may be an internal short, which is also bad.
The power transformer has five terminals that go to the different parts in the amp, the first two are labeled (one has a filled dot and one has a unfilled dot) 6.3V, then one labeled 260V, one labeled "E" and the last labeled 260V all three with unfilled dots. I will take some more pictures and post tomorow.
The two 6.3V are the filament supply. There should be a twisted pair to those lugs. I see white and blue in the first picture, but it would be better to see a close up.
The other three are the high voltage supply. I see red-black-red. This tells me the two reds are the ends of the winding and the black is the center tap. It is logical for the center tap to be in the middle. The center tap should be grounded to the chassis somewhere. The two red wired go to the plates of the rectifier (6X4), pins 1 and 6.
What I don't like, but can't see clearly, is it looks like there is a black wire from the center tap to one of the 6.3V terminals. I would remove that. I don't know why it is there. However, if your filament wiring is old style, where one wire is run to one tube pin and the other tube pin is grounded, that would work. That is one of the reasons I asked for close ups of the transformer and tube pins. Right now, I can't say for sure about this.
Yes this is a difficult task, but I really do feel that I'm learning a lot from this experience!
BTW. will rubber gloves help me from making myself into a piece of toast?
Rubber gloves, the kitchen or sugrical type, are not adequate to protect you. the kind that would work are too clumsy to wear. Dismiss this thought. Rubber shoes are rubber mat are appropriate. It is a good idea to insulate your body from earth, which is a strong ground potential.
Again, thank you for all your help so far, I really appreciate it!
Please don't mention it! People did this for me when I knew nothing. I am passing it forward. I also started out on a very challenging amp, so let's say I feel for you.
Also, I am very favorably impressed with your English. I am assuming it is a second language for you, but I would never know it. I hope what I write to you is clear to you.
I am leaving to visit relatives this afternoon and will return on Saturday. I don't know if I'll have computer access, so maybe someone else will pick up where I left off.
I have some general concerns about whether you've done something to blow your transformers. It doesn't take much to do this, but what you say does not suggest you've made a mistake that would cause trouble. I remain optomistic that transformers are OK. If you have the amp wired up correctly, you should see voltage at the filter caps and on the tube filaments.
One thing you can do is to disconnect everything from the power transformer (PT) and check the AC voltage on the various pairs of terminals. Do not probe to ground here, just check with black on one and red on the other and check each pair. For the high voltage, check the two reds together and then each red to black. On the red+black you should see half the voltage. Also, if you disconnect the PT take ohm readings on each pair of terminals (and to the CT on the high voltage) and post all of what you find.
Good luck. I'll check back in as soon as I can.
Phil
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