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December 18, 2018, 01:24:52 pm

Author Topic: Paramour 1 - 27 mv hum problem  (Read 900 times)

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Offline Paul Birkeland

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Re: Paramour 1 - 27 mv hum problem
« Reply #30 on: November 25, 2018, 02:18:06 pm »
There is something connected on the primary of the OT or on the output of the OT (including the binding posts) that shouldn't be there  or that is touching both terminals.  The signal is sitting there appropriately on the input side of the transformer but isn't making it out.  There should be a little less than 1V of signal at the binding posts under your testing conditions.
Paul "PB" Birkeland

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Offline patrickamory

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Re: Paramour 1 - 27 mv hum problem
« Reply #31 on: November 26, 2018, 01:46:48 pm »
Hi Paul,

I'm stumped. I can't see any short circuits or connections in the area. Is it possible there's something wrong with the OPT?

I've attached some pictures.

Thanks,
Patrick

Offline 2wo

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Re: Paramour 1 - 27 mv hum problem
« Reply #32 on: November 27, 2018, 05:00:05 am »
Sorry to say but a lot of the solder joints don't look good at all, especially the strip adjacent to the outputs. If it were me I would cut/unsolder all of them and start over...John
John Scanlon

Offline patrickamory

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Re: Paramour 1 - 27 mv hum problem
« Reply #33 on: November 27, 2018, 01:00:01 pm »
Sorry to say but a lot of the solder joints don't look good at all, especially the strip adjacent to the outputs. If it were me I would cut/unsolder all of them and start over...John

No worries about criticizing the joints - I made this amp 17 years ago and it was my first project... they are really ugly, I agree.

I'll give that a try and see if it solves the problem. Thanks!

Offline patrickamory

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Re: Paramour 1 - 27 mv hum problem
« Reply #34 on: November 27, 2018, 02:14:47 pm »
Well, I reheated and cleaned up the solder joints on the terminal strip by the outputs.

Reconnected the amp, and now it doesn't power up at all! Which is odd because I didn't touch the PS.

Checked the fuse - intact.

Power cord wiring - intact.

Power supply wiring and joints - look fine.

Checked resistances - all check out except for T25 which should be 200 ohms but is coming up at 1200 ohms - I don't know if this is significant? T25 is where the positive side of the parafeed cap connects with the blue lead on the OPT, which the documentation says connects the primary to the plate.

Checked voltages - 120 VAC from the power cord, 0 VAC at T1 and T2, other side of the PT.

Any further advice?
« Last Edit: November 27, 2018, 02:53:56 pm by patrickamory »

Offline Paul Birkeland

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Re: Paramour 1 - 27 mv hum problem
« Reply #35 on: November 28, 2018, 08:37:37 am »
Based on your descriptions during this thread, every time you are going in to do work on the amp, the problems it has change.  This does indicate lots and lots of flaky solder joints.  Starting over isn't a bad idea, and if you sent it to me for legacy kit repair work, that is likely what I would do.

-PB
Paul "PB" Birkeland

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Offline galyons

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Re: Paramour 1 - 27 mv hum problem
« Reply #36 on: November 28, 2018, 01:03:20 pm »
Based on your descriptions during this thread, every time you are going in to do work on the amp, the problems it has change.  This does indicate lots and lots of flaky solder joints.  Starting over isn't a bad idea, and if you sent it to me for legacy kit repair work, that is likely what I would do.

-PB

I think the PB's advice is spot on!  It is a simple build with relatively few solder joints.  Disassemble, lose the stranded wire and re-solder all of the connections with good solid core wire.  You will likely spend more time chasing problems around the unit than a rebuild would take.

Cheers,
Geary
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Offline patrickamory

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Re: Paramour 1 - 27 mv hum problem
« Reply #37 on: November 30, 2018, 03:01:29 am »
Thanks guys! I'm going to do it.