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December 09, 2019, 10:40:42 PM

Author Topic: dude, where did my power go?  (Read 3259 times)

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Offline fullheadofnothing

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Re: dude, where did my power go?
« Reply #15 on: February 04, 2016, 06:30:18 AM »
These symptoms don't make sense. You say your tubes glow, but you are reading 0.2mV on the heater windings. Are you sure you are properly switching between AC and DC as needed?

Also a lot of your solder joints look problematic. The wires on the binding posts look like they would pop off without much effort. This won't solve the power issue, but do need to be addressed at some point. The IEC inlet and terminal 6 on the transformer also don't look like strong joints. Reheating all your power input related joints might be a good first step. Some of them have a lot of solder, but not clean solder joints. Reheat them so the solder flows smooth. The joints that are barely hanging on may need some more solder while reheating.
« Last Edit: February 04, 2016, 06:44:53 AM by fullheadofnothing »
Joshua Harris

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Offline Stalemate

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Re: dude, where did my power go?
« Reply #16 on: February 04, 2016, 07:21:11 AM »
These symptoms don't make sense. You say your tubes glow, but you are reading 0.2mV on the heater windings. Are you sure you are properly switching between AC and DC as needed?

Also a lot of your solder joints look problematic. The wires on the binding posts look like they would pop off without much effort. This won't solve the power issue, but do need to be addressed at some point. The IEC inlet and terminal 6 on the transformer also don't look like strong joints.

Good morning, Sir. I am absolutely not. After measuring the transformer using this new _Alternating_ current measuring method, I'm happy to report that the Transformer is ok.

God that was embarassing. Apologies all around.

the terminal 6 is soldered from both sides, so it should be ok, thanks for the advice on the binding posts.

Now, I manage to trace the (_alternating_)current all the way to the tube sockets, but from there I get a bit uncertain on how to take it from there.

The measures are the same as well, when using the _Direct_ current measuring setting.

thanks.
v

Offline fullheadofnothing

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Re: dude, where did my power go?
« Reply #17 on: February 04, 2016, 08:18:25 AM »
So what is the AC voltage between 19 and 20 on the power transformer?
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Re: dude, where did my power go?
« Reply #18 on: February 04, 2016, 08:21:12 AM »
it's 170 V


Offline fullheadofnothing

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Re: dude, where did my power go?
« Reply #19 on: February 04, 2016, 08:39:09 AM »
OK. Now do all of the voltage checks on page 65-66. Make sure to use the DC setting.
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Re: dude, where did my power go?
« Reply #20 on: February 04, 2016, 09:04:03 AM »
Hi,

I still get around 1-2V on 1-2 and 19-20, othervise nothing.

v

Offline fullheadofnothing

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Re: dude, where did my power go?
« Reply #21 on: February 04, 2016, 09:26:20 AM »
Measure all terminals  on the 41-45 strip and post those voltages.
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Re: dude, where did my power go?
« Reply #22 on: February 04, 2016, 09:31:16 AM »
41 - 0V
42 - 235V
43 - 0V
44 - 471V
45 - 235V

thanks for your patience!

v

Offline fullheadofnothing

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Re: dude, where did my power go?
« Reply #23 on: February 04, 2016, 09:42:12 AM »
Measure 30 and 31.
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Re: dude, where did my power go?
« Reply #24 on: February 04, 2016, 09:46:40 AM »
30 - 2.4V
31 - 1.4V

Offline fullheadofnothing

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Re: dude, where did my power go?
« Reply #25 on: February 04, 2016, 09:53:39 AM »
Power down the amp and resolder 44L.

Once you have a nice shiny joint that includes all the resistor leads, re-measure 31 and 32.
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Re: dude, where did my power go?
« Reply #26 on: February 04, 2016, 10:47:05 AM »
31 - 2.5
32 - 0

you were right, there was a dodgy connection on one of the resistors

Offline fullheadofnothing

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Re: dude, where did my power go?
« Reply #27 on: February 04, 2016, 10:58:29 AM »
Sorry, I meant 30 and 31.

You have high voltage on one end of those resistors, but not on the other. Since it was on both of them, I assumed a bad connection at 44.  Resoldering should have fixed this problem, but your low voltage at 31 shows that it did not. Can you measure the resistance of each of those resistors? Pictures of the area might also be helpful.
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Re: dude, where did my power go?
« Reply #28 on: February 04, 2016, 12:07:02 PM »
resistance:

44 - 30 - 2.2 mOhm
44 - 31 - 2 mOhm

Voltage

30 - 2.4
31 . 2 .5

The picture shows a right mess - The resistor from 44 to 45 was loose, so I had to desolder 44L, which didn't work out, so it was moved to 44U, after trying, hence the worn look

Are there any particular angles I need to include?

Offline fullheadofnothing

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Re: dude, where did my power go?
« Reply #29 on: February 04, 2016, 12:14:18 PM »
You need to replace the resistors. You can try remeasuring them by putting one probe on either side of the resistor body just to make sure it's not a measurement error, but your amplifier will not function without the right value.
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