Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: Bungler on May 16, 2014, 11:36:55 AM

Title: Crack Built, but Failing Resistance Tests
Post by: Bungler on May 16, 2014, 11:36:55 AM: Hello all,
I just finished my Crack build, and per the manual am checking resistance.
I've got the meter set to 200 ohms (it's a GB GDT-311, (http://www.amazon.com/Gardner-Bender-GDT-311-Function-Multimeter/dp/B000NB85N0), and I'm not getting the right results - please see table below.
I DO know I screwed up one part of the build, but I'm not sure it makes a difference. Here's what I know is not "to spec" per the manual (for reference, I'm looking at "CrackManual 12-17-13.pdf"). On page 32 it says, "Insert the free lead of one resistor through terminal7L. Insert the other free resistor lead through terminal 9L. Solder 3U, 7L, 9L and trim the excess leads." But what I did was to connect to the uppers, not the lowers (7U and 9U). I've attached a photo to show that (BunglerCrack1.jpg).
And the resistance readings (multimeter set to 200 ohms) I'm getting are as follows (also in .jpg attached)
Terminal   Expected   Actual
1   *   1
2   *   Started at .15, down to 0.5
3   0   1
4   *   5.4 down to 0.5
5   *   1
6   2.4k   1
7   2.9k   1
8   0   1
9   2.9k   1
10   2.4k   1
12   0   1
13   will climb slowly to 270k   0.6
14   0   1
20   0   1
22   0   1
B3   2.9k   1
B6   2.9k   1
RCA jacks:
Ground lug    0 ohms   1
Center pin    90K ohmsâ€”100K ohms   1

Thanks,
Bungler
Title: Re: Crack Built, but Failing Resistance Tests
Post by: Paul Birkeland on May 16, 2014, 11:39:56 AM: What does your meter say if you have it on Ohms/200 and you touch the red and black probes together?
Title: Re: Crack Built, but Failing Resistance Tests
Post by: Bungler on May 16, 2014, 12:21:39 PM: It starts at .18 - .35, bounces around a bit, and settles on .4 to .5
Title: Re: Crack Built, but Failing Resistance Tests
Post by: Grainger49 on May 16, 2014, 12:48:06 PM: That is what you get for zero. All of the measurements that should be zero should be measured on the lowest resistance scale and will be a few tenths of an ohm higher than touching the two meter leads together.
Title: Re: Crack Built, but Failing Resistance Tests
Post by: Bungler on June 03, 2014, 07:47:05 AM: Thanks, Grainger.
Do you have any idea why the 9, 10, B3 and B6 readings are so far off?
The amp does work, but the I get intermittent spitting bursts during playback.
Thanks.
Title: Re: Crack Built, but Failing Resistance Tests
Post by: fullheadofnothing on June 03, 2014, 08:04:58 AM: You have set your meter incorrectly. You said you used the 200Î© scale, which will read as overlimit for anything over 200Î©. Your meter is displaying "1" for overload, most likely the "1" is displayed all the way at the left end of the screen, rather than at the right end where it would display an actual reading.

Repeat your resistance measurements in the proper range.
Title: Re: Crack Built, but Failing Resistance Tests
Post by: Paul Birkeland on June 03, 2014, 08:28:36 AM: Quote from: Bungler on June 03, 2014, 07:47:05 AM
Do you have any idea why the 9, 10, B3 and B6 readings are so far off?

Your resistance readings that you reported look about spot on for those terminals.