S.E.X. Failed Resistance Check

alecksbee · 507

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Offline alecksbee

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on: November 24, 2024, 04:35:13 AM
Hello everyone, I just finished assembling a S.E.X. kit and during the process of checking resistance found some outliers. I did try and clean up some ugly looking joints but to no avail. Here's the offenders:
T15: 6Ω
T30: Starts around 100Ω and climbs, I stopped measuring when it hit 200Ω (denoted by 100++Ω)
T31: 100++Ω
T32: 100++Ω
H2: 100++Ω
H4: 100++Ω
H7: 100++Ω

Attached are a few pictures of the build, do note I did take out the .1Ω 5W resistor as it had the ugliest of joints. It was a tough spot for me to get it back in so I gave him some legs.
Thanks in advance!



Offline Paul Birkeland

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Reply #1 on: November 24, 2024, 05:27:09 AM
Can you let me know the make and model number of the meter you're using?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline alecksbee

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Reply #2 on: November 24, 2024, 05:39:50 AM
Can you let me know the make and model number of the meter you're using?

Hey Paul, I have an Ideal 61-327 that I picked up from the local hardware store around the pandemic, for sure it's not the most expensive unit out there



Offline Paul Birkeland

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Reply #3 on: November 24, 2024, 05:44:36 AM
Can you redo those readings on the 4M setting? (or let me know which setting you were using for the readings you took?)

Manual range meters need a little extra attention when using.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline alecksbee

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Reply #4 on: November 24, 2024, 06:02:35 AM
Can you redo those readings on the 4M setting? (or let me know which setting you were using for the readings you took?)

Manual range meters need a little extra attention when using.

Here's what I got:
T15: 0Ω
T30: 0Ω
T31: 0Ω
T32: 0Ω
H2: 0Ω
H4: 0Ω
H7: 0Ω



Offline Paul Birkeland

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Reply #5 on: November 24, 2024, 06:15:59 AM
Can you post a picture of the screen of your meter measuring terminal 31?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline alecksbee

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Reply #6 on: November 24, 2024, 06:26:09 AM
Can you post a picture of the screen of your meter measuring terminal 31?



Offline Paul Birkeland

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Reply #7 on: November 25, 2024, 02:25:51 PM
If you move the meter to the beep setting, does this connection produce a tone? 

I would suspect issues with the shielded twisted pair wiring causing a short between the heater wires inside the STP and the drain wire/shield that is used to shield it.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline alecksbee

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Reply #8 on: November 25, 2024, 03:03:28 PM
If you move the meter to the beep setting, does this connection produce a tone? 

I would suspect issues with the shielded twisted pair wiring causing a short between the heater wires inside the STP and the drain wire/shield that is used to shield it.

Earlier today I went through all of the instructions again and discovered that the leg for the 8.2KΩ resistor wasn't soldered in to 20L at all! Fixed the majority of the resistance checks. There's still a few ones remaining though:

H3: 1800Ω
H4: same odd rising number, up at 4M it reads 0Ω
H7: same as above


EDIT: I did go back and tested everything with the beep setting, did not beep on T30, however pretty much all my previous readings were bad? They're similar to the original post now. The meter does beep when I put it on T15. Very odd
« Last Edit: November 25, 2024, 04:18:04 PM by alecksbee »



Offline Paul Birkeland

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Reply #9 on: November 25, 2024, 06:55:11 PM
I think I'd be getting a different meter... are you in the US?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline alecksbee

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Reply #10 on: November 26, 2024, 02:57:40 AM
I think I'd be getting a different meter... are you in the US?

Yes! Any suggestions are welcomed



Offline Paul Birkeland

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Reply #11 on: November 26, 2024, 05:12:13 AM

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline alecksbee

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Reply #12 on: November 27, 2024, 03:58:22 AM
https://www.amazon.com/Neoteck-Multimeter-Multimeters-Resistance-Transistor/dp/B01NAVAT9S?th=1

Hey Paul, got the new multimeter in this morning and did some measurements, basically the same as before:

T15: 2Ω
T30: Starts around 100Ω and climbs, I stopped measuring when it hit 200Ω (denoted by 100++Ω)
T31: 100++Ω
T32: 100++Ω
H2: 100++Ω
H3: 700++Ω
H4: 100++Ω
H7: 100++Ω

Do you think it would be worth trying to re-do the STP you suspected was shorting out? I have about 10" spare



Offline Paul Birkeland

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Reply #13 on: November 27, 2024, 05:05:13 AM
T30: Starts around 100Ω and climbs, I stopped measuring when it hit 200Ω (denoted by 100++Ω)
Can I see a picture of what this looks like on your meter?

Definitely do not mess with any of the wiring yet.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline alecksbee

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Reply #14 on: November 27, 2024, 05:27:38 AM
Can I see a picture of what this looks like on your meter?

Definitely do not mess with any of the wiring yet.

Sounds good, here's what it stabilized at with the new meter, I took a short video as well below:
https://streamable.com/sbmlob