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October 06, 2022, 07:56:03 PM

Author Topic: Resistance check failure, please help [resolved]  (Read 129 times)

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Offline smodtactical

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Resistance check failure, please help [resolved]
« on: July 02, 2022, 02:44:59 PM »
I have starred the ones that have failed.

I tried to reflow and add solder to 27 and PT 6 + 7
but didnt work

Ground lug 23.6
1 24 ohm
2 1.5
3 23.7
4. 624
5. Ol
6. 2.34 mega ohm
7. Ol
8. 23.8
9. 9.9 kilo ohm
10. Ol
11. 1.78 mega ohm
12. 1.3
13. 23.8
14. 600
15. Ol
16.1.3 mega ohm
17. Ol
18. 23.7
19. 9.7 kohm
20. Ol
21. 1 mega ohm
22. 23.8
23. 1.3
24. 0.8 mega ohm
25. 23.5
26. 201
27. Ol ****************
28. 0.7 mega ohm
29. 4.1 mega ohm
30. 401
31.400
32. 23.8
33. Ol
34. Ol
35. 23.8

A1 624
A2 ol *********
A3 ol
A4 523 kilo ohm
A5 230
A6 12.5
A7 ol **********
A8 624

B1 625
B2 OL ***********
B3 OL
B4 2.84 MEGA ohms
B5 100 kilo ohm
B6 100 kilo ohm
B7 100.7 kilo ohm ***********
B8 624

Images:

https://cdn.discordapp.com/attachments/594534273483276298/992953107657011231/unknown.png
https://cdn.discordapp.com/attachments/594534273483276298/992953137570779156/unknown.png
https://cdn.discordapp.com/attachments/594534273483276298/992953160438120458/unknown.png
https://cdn.discordapp.com/attachments/594534273483276298/992953211596058676/unknown.png


« Last Edit: July 03, 2022, 05:32:32 AM by Paul Birkeland »

Offline Paul Birkeland

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Re: Resistance check failure, please help
« Reply #1 on: July 02, 2022, 02:57:53 PM »
Can you repost your resistances that aren't correct and leave off all the ones that are OK?

I see a missing screw on one of your terminal strips.

I see lots of wires that should be stripped back 1/4" but are stripped back more like 1"  This can cause unpredictable reliability issues and may require some rework on your end.

The last power supply cap that lays down against the chassis needs to be installed closer to the terminal strip so it fits inside the wood base.

You have your power transformer wired for 110V or less which is rather uncommon, what is your wall voltage?

The 220 ohm resistors on the octal sockets are not installed as instructed in the manual.

The white wires leaving pins 2/8 on each socket are stripped back way too much (as mentioned above), and if they touch pins 2 or 7 you will destroy your preamp.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline smodtactical

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Re: Resistance check failure, please help
« Reply #2 on: July 02, 2022, 03:07:21 PM »
Just found it! I was missing the screw and lug right under terminal 27. Once I screwed that in all the failed checked are in agreement with the resistance check.

Offline smodtactical

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Re: Resistance check failure, please help
« Reply #3 on: July 02, 2022, 03:08:15 PM »
Can you repost your resistances that aren't correct and leave off all the ones that are OK?

I see a missing screw on one of your terminal strips.

I see lots of wires that should be stripped back 1/4" but are stripped back more like 1"  This can cause unpredictable reliability issues and may require some rework on your end.

The last power supply cap that lays down against the chassis needs to be installed closer to the terminal strip so it fits inside the wood base.

You have your power transformer wired for 110V or less which is rather uncommon, what is your wall voltage?

The 220 ohm resistors on the octal sockets are not installed as instructed in the manual.

The white wires leaving pins 2/8 on each socket are stripped back way too much (as mentioned above), and if they touch pins 2 or 7 you will destroy your preamp.

Yup you were right. Thanks for all this going to look through and see.

Offline smodtactical

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Re: Resistance check failure, please help
« Reply #4 on: July 02, 2022, 03:14:35 PM »
"I see lots of wires that should be stripped back 1/4" but are stripped back more like 1"  This can cause unpredictable reliability issues and may require some rework on your end.

The last power supply cap that lays down against the chassis needs to be installed closer to the terminal strip so it fits inside the wood base."

Will work on that, thanks.

"You have your power transformer wired for 110V or less which is rather uncommon, what is your wall voltage? "

I just checked the instructions again and I seem to have followed the 110-120 volts. Namely I have a wire going from 33 U to terminal 4 (red). Please let me know if this is wrong.

"The 220 ohm resistors on the octal sockets are not installed as instructed in the manual."

In what way? Do you mean just the way they are positioned?

"The white wires leaving pins 2/8 on each socket are stripped back way too much (as mentioned above), and if they touch pins 2 or 7 you will destroy your preamp."

Will work on that.


Offline Paul Birkeland

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Re: Resistance check failure, please help
« Reply #5 on: July 02, 2022, 03:44:13 PM »
The 110V-130V wiring configuration does not have a connection at pin 2 of the power transformer.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline smodtactical

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Re: Resistance check failure, please help
« Reply #6 on: July 02, 2022, 06:58:42 PM »
The 110V-130V wiring configuration does not have a connection at pin 2 of the power transformer.

Paul you are totally right. No idea why I did that. Undid it and voltages check out. Thanks so much man! You are doing a great job.