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December 03, 2022, 08:35:35 PM

Author Topic: Resistance check: terminal 6 reads infinite, not 0 ohms [resolved]  (Read 93 times)

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Offline soundsliketubes

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Resistance check: terminal 6 reads infinite, not 0 ohms [resolved]
« on: September 28, 2022, 10:53:40 AM »
Crack newbie here.  I have the amp wired up and am doing the resistance checks.  All looked good except:

Terminal 6

which reads 1 on my meter, like * in the manual I think.  I tried reheating that solder joint but still reads infinite.   

Any ideas what to look for?

Thanks.
« Last Edit: September 28, 2022, 04:46:57 PM by Paul Birkeland »

Offline soundsliketubes

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Re: Resistance check: terminal 6 reads infinite, not 0 ohms
« Reply #1 on: September 28, 2022, 11:17:08 AM »
Adding picture of wiring.

Offline Paul Birkeland

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Re: Resistance check: terminal 6 reads infinite, not 0 ohms
« Reply #2 on: September 28, 2022, 01:12:03 PM »
The most important thing is not to try to use your Crack until this is resolved.  How does terminal 10 read?  Can you post some extra photos of the wiring around the headphone jack?
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline soundsliketubes

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Re: Resistance check: terminal 6 reads infinite, not 0 ohms
« Reply #3 on: September 28, 2022, 02:35:19 PM »
Thanks Paul.  I have not applied power and won't until this is figured out.  All of the other Ohm measurements looked correct.

Terminal 10 is 0 ohms.

Attached are more pics.

Offline Paul Birkeland

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Re: Resistance check: terminal 6 reads infinite, not 0 ohms
« Reply #4 on: September 28, 2022, 02:51:49 PM »
Is the read wire leaving the headphone jack attached to terminal 6?

Can you measure the DC resistance between ground (terminal 12) and the middle outer lug of the headphone jack? How about the middle inner lug of the headphone jack?
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline soundsliketubes

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Re: Resistance check: terminal 6 reads infinite, not 0 ohms
« Reply #5 on: September 28, 2022, 03:05:15 PM »
Yes, the red wire from the inner middle headphone jack is attached terminal 6.

Both middle outer and middle inner lug of headphone jack measure infinity (1 on my meter).

Offline Paul Birkeland

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Re: Resistance check: terminal 6 reads infinite, not 0 ohms
« Reply #6 on: September 28, 2022, 03:06:45 PM »
The problem with that reading is that the white wire that goes to terminal 10 is showing ground, and it gets its grounds after what would feed terminal 6. 

What is the DC resistance to ground for the bottom outer lug and the two upper lugs on the headphone jack? 

Also double check that both of the black wires on the headphone jack are captured by solder.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline soundsliketubes

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Re: Resistance check: terminal 6 reads infinite, not 0 ohms
« Reply #7 on: September 28, 2022, 03:14:20 PM »
All three of those are 0 ohms.

The black wires appear solidly connected to the lower inner lug.

Offline Paul Birkeland

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Re: Resistance check: terminal 6 reads infinite, not 0 ohms
« Reply #8 on: September 28, 2022, 03:16:13 PM »
OK, well the bare wire/leads that snake up through the outer terminals on the headphone jack are not well connected and/or soldered at the middle lug.  This is extremely implausible, as you have 0 ohms at the bottom outer lug and 0 ohms at the outer top lug, and they are connected through the middle lug that doesn't read 0 ohms, but it is still possible.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline soundsliketubes

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Re: Resistance check: terminal 6 reads infinite, not 0 ohms
« Reply #9 on: September 28, 2022, 03:29:39 PM »
That was it!   Thanks Paul.   I resoldered that connection and now 0 Ohms on terminal 6.  And I checked the other resistances too and they match with page 47.

Thank you for finding my lame soldering error!