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December 11, 2019, 05:11:28 PM

Author Topic: dude, where did my power go?  (Read 3262 times)

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Offline Stalemate

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dude, where did my power go?
« on: January 31, 2016, 09:39:03 AM »
Hi,
I've assembled the stereomour II kit, following the excellent instructions provided.

All my resistance tests are a-ok, but when I do the power tests, I get very low values, so low that I was wondering if my multimeter is acting up, but control tests show expected results, so I'm a bit lost here.

I've checked the transformator and gets the expected results from "secondary power check", I've checked the wiring, but the first check comes out at 2 VDC, while the expected result is 360something.

how do I troubleshoot this? I don't dare connecting it to anything, since as far as I know, there are 358 unaccounted Volts in there somewhere...

I'm a newbie, so be nice...

Offline Stalemate

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Re: dude, where did my power go?
« Reply #1 on: February 01, 2016, 02:15:02 AM »
Hm, so after doing a quick "RTFM" on what to look for, I turned my attention to the C4S-board. I measured the transistors, and got these measurements on the "bipolar" - 1-3 ok, 1-2 null, 2-3 ok, 3-1 ok, while the other didn't give any measurements on any combination - so is this consistent with what I describe?

oh, and the leds are dark.

any help appreciated!

Offline kgoss

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Re: dude, where did my power go?
« Reply #2 on: February 01, 2016, 05:43:22 AM »
Do a complete voltage check and post any terminals that are off by more than 10%. PB or someone else at Bottlehead will help you resolve the problem. But they need the voltages that are off plus the terminal numbers to troubleshoot.
Ken Goss

Offline Stalemate

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Re: dude, where did my power go?
« Reply #3 on: February 01, 2016, 09:02:43 AM »
Thanks for the advice!
I managed to break one of the mje-transistors when I was measuring its function, so I need to order some new ones :(

I'll be back!

v

Offline Stalemate

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Re: dude, where did my power go?
« Reply #4 on: February 03, 2016, 02:18:11 AM »
I rebuilt the C4S and measured the function of the transistors ok, I also doublechecked the solders, and everything seems fine.

I then proceeded to check my solders, and replumed where I saw it necessarry. All the resistance checks are ok, so I plug in the tubes and power, and get the following:

1: 2VDC
2: 2VDC
3-18 : 0 VDC
19: 2VDC
20: 2VDC

The rest are dead, 0 VDC
I rechecked the wiring on the OT and PT (connectivity + config) ok

The tubes light up, I'd say a bit weak, but I haven't seen an functioning amp,so I couldn't say whether it's within the norm.

please advise..

best regards
Vegar

Offline Paul Birkeland

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Re: dude, where did my power go?
« Reply #5 on: February 03, 2016, 05:59:17 AM »
Perform the power transformer voltage measurement for the 160V terminals and let us know what AC voltage you get there.

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Stalemate

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Re: dude, where did my power go?
« Reply #6 on: February 03, 2016, 06:38:06 AM »
Thanks Paul,

I'm actually not able to measure any voltage over those terminals.

I've double checked my configuration, I have 236VAC in the mains, (which I'm able to measure on terminals 2-4)  so I configured it by connecting terminal 1 to 6, I've checked my soldering for connectivity, and it's ok.

what more tests can I do?

br
Vegar

[edit]
When I short out the 160V (19-20), the fuse blows, which should mean there is something touching something else in there.

[/edit]
« Last Edit: February 03, 2016, 07:08:47 AM by Stalemate »

Offline Doc B.

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Re: dude, where did my power go?
« Reply #7 on: February 03, 2016, 07:58:11 AM »
You really don't want to test the transformer by shorting out the high voltage secondary. That can damage it. I suggest going back to the power transformer secondary voltage tests and check all of them - 19 and 20, 15 and 9, 14 and 11.
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline Stalemate

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Re: dude, where did my power go?
« Reply #8 on: February 03, 2016, 08:00:42 AM »
So I did - and there is no power there. Shorting out the 19 and 20 was an accident, I was clumsy and managed to touch both poles with the multimeter.

v

Offline Doc B.

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Re: dude, where did my power go?
« Reply #9 on: February 03, 2016, 09:28:32 AM »
Did you test the other secondaries, 3.3V and 6.3V?
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline Stalemate

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Re: dude, where did my power go?
« Reply #10 on: February 03, 2016, 09:43:19 AM »
Hi,
Yes I did, The measurements are neglible, the multimeter a very low current (~0.2 mV) on both.

So to summarize, I'm able to trace the 236 VAC from the wall, via the 46-48 mounts to pin 2 and 4.
I've connected pin 1 to pin 6 to configure the transformer for that current. I'm able to measure 0 ohms on all my connections, meaning the solder and cable is ok, but none of the secondaries gives any reading, other than flutter on the meter. What am I missing here?

thanks
V

Offline Paul Birkeland

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Re: dude, where did my power go?
« Reply #11 on: February 03, 2016, 09:48:54 AM »
Post a photo of your black and red power supply jumpers that attach from the terminal strip to the set of 6 lugs.
-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Stalemate

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Re: dude, where did my power go?
« Reply #12 on: February 03, 2016, 10:02:38 AM »
Hi,
Here you go

v

Offline Deluk

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Re: dude, where did my power go?
« Reply #13 on: February 03, 2016, 11:42:14 AM »
Shouldn't the black wires be soldered to the earth tag at the bottom of the first picture?

Offline Stalemate

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Re: dude, where did my power go?
« Reply #14 on: February 03, 2016, 11:41:51 PM »
Shouldn't the black wires be soldered to the earth tag at the bottom of the first picture?

You're right, so I did, but to no avail...

br
V