Couple of resistance check issues (SOLVED)

jboehle · 1321

0 Members and 1 Guest are viewing this topic.

Offline jboehle

  • Jr. Member
  • **
    • Posts: 45
on: May 01, 2014, 08:05:17 AM
Hi, finished my Crack last night.  Did the resistance check and have two issues.  Before I get to those, I wired tab 4 on the transformer to terminal 14 in the Crack as is suggested in the manual.  I am using an HP 3478A meter in 2 wire resistance, auto-ranging mode.

Reading at terminal 13 - starts at 30M ohms, slowly drops until 2-3M ohms, then meter switches to K ohms range, then slowly grows from 150K to 270K ohms.  I've had the meter hooked up here for ~15 minutes and it's currently reading 262.K.  The manual does not mention the first part of that (starting at 30M ohms and dropping).

Reading at terminal 22 - 6.8 ohms.  The manual says this should be 0 ohms.

All of my other resistance checks matched the manual.
« Last Edit: May 01, 2014, 04:47:12 PM by jboehle »



Offline jboehle

  • Jr. Member
  • **
    • Posts: 45
Reply #1 on: May 01, 2014, 08:15:10 AM
I solved the 2nd issue.  I checked readings at terminals 11, 16, & 17 and those were all 0 ohms, so I thought maybe the lock washer on the screw at terminal 22 did not fully penetrate the paint on my transformer bell.  I tightened the screw at terminal 22 down harder, and now terminal 22 reads 0 ohms as well.

For my other issue, I went back and read the manual and it does say that the * readings will vary from meter to meter, so I'm guessing my issue at terminal 13 is a non-issue, since it does eventually slowly grow to 270K ohms, and I'm probably ready to power up.



Offline Paul Joppa

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 5778
Reply #2 on: May 01, 2014, 12:10:26 PM
That slow ramping of the reading is because the ohmmeter is charging a capacitor; apparently when your meter changes range is also changes the voltage it uses for the measurement, thus reversing some of the charge it put on in the first place.

Paul Joppa


Offline jboehle

  • Jr. Member
  • **
    • Posts: 45
Reply #3 on: May 01, 2014, 04:36:26 PM
Powered up without incident!  Listened to it a good part of the afternoon, it sounds amazing with my Senn HD 650.  Below are my voltage check numbers.  All are within the 10-15% variation range.  I think my AC line voltage was 122 at the time.

1. 79
2. 175
3. 0
4. 175
5. 78
6. 0
7. 108
8. 0
9. 105
10. 0
11. 0
12. 0
13. 175
14. 0
15. 197
20. 0
21. 219

A1. 78
A2. 0
A4. 0
A5. 0
A6. 79
A7. 0
A9. 0

B1. 79
B2. 175
B3. 108
B4. 78
B5. 175
B6. 105
B7. 0
B8. 0

I have the Speedball and Crackheadphone up next.  :)



Offline jboehle

  • Jr. Member
  • **
    • Posts: 45
Reply #4 on: May 01, 2014, 04:41:38 PM
Oh yeah, and mine is bone stock at the moment, other than painting the chassis plate and transformer bell.