problem with resistance checks on stereomour II [resolved]

Smoses01 · 1348

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Offline Smoses01

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Have just completed my stereomour II and when doing resistance checks, I get no response when checking 47 and 48. I have checked continuity between black wires on 47 and where they connect to power supply, and likewise have checked continuity between red wires on 48 and where they are connected to power supply. These continuity checks are normal. But, when checking continuity with a meter, I realize the meter is completing the circuit, while when doing resistance checks on 47, 48 the internal connections within the power supply have to complete the circuit. When I did the initial voltage tests, as outlined in the manual on page 31 (power transformer secondary test), it checked out ok and I know I didn't do anything to cause a short. 
So, with getting no response what-so-ever when resistance testing 47 and 48, does that indicate a power supply problem? With everything wired up, how can I definitively tell if there is something else I have over-looked there?
« Last Edit: March 24, 2021, 06:48:06 AM by Paul Birkeland »



Offline Paul Birkeland

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Reply #1 on: March 23, 2021, 10:05:00 AM
Have just completed my stereomour II and when doing resistance checks, I get no response when checking 47 and 48.
And what does the manual say you should get?


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Smoses01

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Reply #2 on: March 23, 2021, 12:00:27 PM
the manual says that both 47 and 48 should be wandering in the tens or hundreds of K ohm or higher range.



Offline Paul Birkeland

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Reply #3 on: March 23, 2021, 12:10:46 PM
What is the next sentence in the manual after that?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Smoses01

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Reply #4 on: March 24, 2021, 01:43:34 AM
The next sentence says- "what you want to watch out for is a zero reading at one of these terminals, which would indicate that something is mis-wired.
I'm not getting a zero reading, but no response at all. (on my fluke meter this is just showing no change from the starting screen of OL). On #46, I am correctly getting a reading of zero ohms, because that is to ground.
Thanks for replying to me. (This is my first time using the forum). This is my third kit; I have previously successfully built a crack and the sex 3.0.



Offline Smoses01

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Reply #5 on: March 24, 2021, 03:40:31 AM
So, to be clear: on 46 I am getting a zero ohm reading, which is what is expected.  On 47 and 48 I am getting no response, which on my meter is OL. (open lead).  There, I should be getting response of meter wandering in tens or 100s of k ohms.  (Sorry if I am not explaining things clearly at times).



Offline kgoss

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Reply #6 on: March 24, 2021, 03:45:53 AM
While it is not entirely obvious "0L" means "over limit" which is not zero.  At some test points meters behave differently and Bottlehead points those out in each manual.  Since you are not measuring zero you are good to continue the build.

Ken Goss


Offline Smoses01

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Reply #7 on: March 24, 2021, 04:18:07 AM
With my meter when I put it to resistance setting, it begins with the screen which says OL, then as you connect the leads to something you are testing, that screen changes to show the resistance value. I am thinking something is perhaps wrong with the power supply because when I hook up the leads to measure 47 or 48 it doesn't change from the starting screen which says OL. ( ie. no response from the meter).
I will continue and for the time being and go on to testing other areas. Thank you.



Offline Paul Birkeland

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Reply #8 on: March 24, 2021, 06:04:24 AM
You didn't get a low reading on those terminals, so there is no problem.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Smoses01

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Reply #9 on: March 24, 2021, 06:40:31 AM
ok, thanks.



Offline Doc B.

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Reply #10 on: March 24, 2021, 07:07:40 AM
The readings wander because the battery in the meter charges a cap in the circuit where you are measuring. If the cap already has charge on it (and it can) the meter might read over limit, which means that the climbing aspect of the "wandering" reading would have already occurred and the cap would be charged up to a reading over the meter's limit. None of this is a zero reading, and anything but zero is OK.

Dan "Doc B." Schmalle
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Bottlehead Corp.


Offline Smoses01

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Reply #11 on: March 25, 2021, 02:34:50 AM
But Doc, (Thanks for replying), I am getting no response on the meter at all, as if hooked to an incomplete (open) circuit. My fluke meter when set to resistance setting initially says OL before you even hook up the leads. When I hook up the negative lead to ground and the positive to 47 or 48 there is no response on my meter as if I am testing an open (incomplete) circuit.  I have checked my solder connections, and continuity with each of the black wires (coming from 47 to the power supply) and red wires (coming from 48 to the power supply), and I am getting continuity.
I think I need to complete the rest of my resistance checks, and then, if ok, when I hook up power, I will certainly know if there is power coming through or not to and from the power supply. Thanks. (Hope I explained this clearly).



Offline Adrian

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Reply #12 on: March 25, 2021, 02:43:30 AM
If the caps Doc B. mentions are fully charged, then they are effectively an "open" in that part of the circuit you are trying to measure using the the DC power from your meter.  All is well.

Adrian C.

VPI Prime w/Ortofon Quintet Black MC/Rothwell MCL Lundahl SUT/EROS/Submissive (3 output mod)/Mainline/Crack - Speedball/S.E.X. 2.1 - C4S/S.E.X. 3.0 - C4S/Paramounts - Blumenstein 2.2 Mini-Max w/DOF mod -Senn HD600/Viso HP50/Focal Elear.


Offline Smoses01

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Reply #13 on: March 25, 2021, 04:21:24 AM
Thank you!!



Offline Paul Birkeland

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Reply #14 on: March 25, 2021, 05:19:06 AM
But Doc, (Thanks for replying), I am getting no response on the meter at all, as if hooked to an incomplete (open) circuit.
It is, it's the primary of the power transformer.  It doesn't connect to anything else in the amp.  We use the * there because some meters won't always show that as an open circuit, and we really just want to be sure there are no shorts between the primary and anything else in the amp.

As the manual states, what you want to watch out for here is a 0.  You have the furthest reading from 0.  These resistances are OK. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man