Crack Resistance Check before Voltage Check

bmilcs · 5145

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Offline bmilcs

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on: September 18, 2016, 02:59:12 PM
I just want to confirm that I'm doing this correctly:

https://www.amazon.com/gp/product/B000X5TSUA/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
Firstly, Here is my ohm reader.

The only way I am getting correct measurements that make sense is with 200K dial locked in. I assumed the 20k would be what I wanted and should show 2.9k but nay. The only way I could get the readings that were specified in the Crack manual were on the 200k setting.

I've read the resistance check page a dozen times. I finally came to understand that I was supposed to:
1) Connect the black alligator clip to 12 on the transformer.
2) Somehow connect 12 and the ground, a spare alligator clip was recommended.

I used the spare wire from the kit and made little hooks at the end to make the connection and do the tests.

I was receiving 2.9 where I was supposed to receive 2.9.

My RCA jacks came out to 107.9 and 108.0 so that seems good yes?

0's came up as 0's.

* would steadily climb. They generally were around 30 and kept going up the longer I stayed on them.

Am I safe to continue?
« Last Edit: September 18, 2016, 03:02:05 PM by bmilcs »



Offline fullheadofnothing

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Reply #1 on: September 18, 2016, 03:03:57 PM
DO NOT use terminal 12 on the transformer. Use terminal 12.

Every connection to the transformer is explicitly called out as being on the transformer. The resistance instructions do not use the word transformer, and therefore you should not use the transformer terminal.

Joshua Harris

I Write the Manuals That Make The Whole World Sing
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Offline bmilcs

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Reply #2 on: September 18, 2016, 03:56:43 PM
Thank you. It's been an exhausting weekend and running on very little sleep. This is exactly why I waited to test it for real and posted here first.



Online Doc B.

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Reply #3 on: September 18, 2016, 04:01:57 PM
Slow down. Wearing your self out building an amp and test firing it is a recipe for disaster. Take a break from it and come back to it when you feel fresh. Recheck all your work, then take the resistance measurements.

Dan "Doc B." Schmalle
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Offline bmilcs

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Reply #4 on: September 18, 2016, 04:18:55 PM
Slow down. Wearing your self out building an amp and test firing it is a recipe for disaster. Take a break from it and come back to it when you feel fresh. Recheck all your work, then take the resistance measurements.

I was in bed when I typed all this out :D. Beat ya to it. I triple checked all my solder joints before going to resistance check. I am very confident in my soldering skills and finished product; I just didn't understand the instructions for resistance checking. I just got up to brush my teeth and set my DMM to 200k, with the black clamped to terminal 12 (not the transistor) and a temporary wire running from t12 to ground. I get exactly the numbers specified in the manual.

For the * values, they start at roughly 22 and climb from there. The main thing I'm looking for is 0 resistance where there shouldn't be. Right?

It all checks out. If I were to make one change to the manual so far, it would be the resistance check part. I found it a little confusing. Pictures do wonders.
« Last Edit: September 18, 2016, 04:23:56 PM by bmilcs »



Offline bmilcs

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Reply #5 on: September 18, 2016, 04:22:57 PM
After rereading this, I see where it may seem as though I'm haphazardly throwing this thing together. I assure you.. I'm not :).

I read each instruction 5 times and checked each picture over and over before soldering in place.



Offline fullheadofnothing

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Reply #6 on: September 18, 2016, 04:36:44 PM
Terminal.

Twelve.

Is.

Ground.

That is why you attach the black probe there.

DO NOT ADD ANY WIRES.

They are not needed.

They are not mentioned IN ANY WAY in the manual.

They will create a ground loop that will create issues. Read the instructions and follow them. 

Joshua Harris

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Offline bmilcs

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Reply #7 on: September 19, 2016, 05:11:16 AM
1) Thank you for clearing this up. I completely understand at this point.

2) Let me explain why I misunderstood after reading this paragraph over a dozen times and asking my wife what she thought as well.

*Again, I am clearly a layman and am new to this whole process. I may be stupid but I am not dumb and that is why I made sure before moving on to check with the forums.*



(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F3Lc4QXX.png&hash=c0384d3b45e47bda1772d73b70c07f9be4ca70e4)



Quote
Attach the negative lead (typically black) of a volt-ohm meter to terminal 12.  (I was blatantly wrong regarding the transistor 12 vs terminal 12)

BUT...

Use of a clip lead to connect the black test lead to the ground buss will free one hand, making testing much easier and safer.

With my limited understanding, "connect the black test lead", which I clipped to Terminal 12 due to the first sentence, "to the ground buss", I remembered and checked back in the manual to the ground nut/clip/thingy in the beginning stages of the manual.  There weren't any photos included in this section and so these were my assumptions.

So, in my clearly moronic and uneducated brain, I thought okay: I don't have any extra alligator clips. I do have this excess wire and that should create a temporary connection for the purpose of this test. I didn't understand why I would do this but I'm not questioning it. I cut 7mm off each end of the excess wire and simply hooked it around the ground and T12 as you explained earlier. Then, I went about the DMM test and afterwards removed the wire from the project.

I'm sorry for aggravating you. I am not an electrician. This is a beginners kit and I didn't think having questions like this would be met with hostility. Then again, it's hard to read emotion and attitude with just text.




Offline bmilcs

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Reply #8 on: September 19, 2016, 05:19:15 AM
My RCA jacks differ by .2 ohm. Will this be an issue? One is 108.4 and the other is 108.6.

Aside from this, my ohm checks continue to be spot on. I will do my voltage checks after work



Offline Paul Birkeland

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Reply #9 on: September 19, 2016, 05:32:43 AM
My RCA jacks differ by .2 ohm. Will this be an issue? One is 108.4 and the other is 108.6.

Aside from this, my ohm checks continue to be spot on. I will do my voltage checks after work
This will not cause any problems.  It's normal to see one at 90K and the other at 110K.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline fullheadofnothing

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Reply #10 on: September 19, 2016, 05:39:57 AM
There is no hostility here. You just seem to be having trouble comprehending, so I was attempting to explain away any possible doubt. The ground buss is the whole series of ground wires. The safety ground is a point on the ground buss, but it is not the be-all end-all of the ground buss.



The first sentence is an instruction, attach the lead to 12.

The second sentence is an explanation of why you would want to use a clip lead. It is a recommendation of best form for following the instruction provided in the previous sentence.

Joshua Harris

I Write the Manuals That Make The Whole World Sing
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Offline bmilcs

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Reply #11 on: September 19, 2016, 06:41:07 AM
This will not cause any problems.  It's normal to see one at 90K and the other at 110K.

Great to hear.

With the * indicators, steadily increasing values is what I'm looking for right?



Offline bmilcs

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Reply #12 on: September 19, 2016, 06:44:39 AM
There is no hostility here. You just seem to be having trouble comprehending, so I was attempting to explain away any possible doubt. The ground buss is the whole series of ground wires. The safety ground is a point on the ground buss, but it is not the be-all end-all of the ground buss.



The first sentence is an instruction, attach the lead to 12.

The second sentence is an explanation of why you would want to use a clip lead. It is a recommendation of best form for following the instruction provided in the previous sentence.

I do appreciate clearing it up. Sorry for being quick tempered and explaining.

One last question guys, my large GE tube has very dirty metal legs on it and the metal seems oxidized on the outside. I didn't realize it until I removed it from the glow test. Is this normal?
« Last Edit: September 19, 2016, 06:47:00 AM by bmilcs »



Offline Paul Birkeland

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Reply #13 on: September 19, 2016, 06:47:28 AM
With the * indicators, steadily increasing values is what I'm looking for right?
You're looking for something that isn't close to 0.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Paul Birkeland

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Reply #14 on: September 19, 2016, 06:48:05 AM
One last question guys, my large GE tube has very dirty metal legs on it and the metal seems oxidized on the outside. I didn't realize it until I removed it from the glow test. Is this normal?
6080's haven't been made for a long time.  The metal is old, and will show some age.  This is normal.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man