Voltage problems

jamesondrums · 1919

« previous next »
Pages: 1 2   Go Down

0 Members and 1 Guest are viewing this topic.

Offline jamesondrums

  • Jr. Member
  • **
    • Posts: 25
on: May 28, 2020, 09:26:02 PM
My voltage readouts are not right and my led's are not working. Not sure what to do from here. My voltages read

1. -1.2mv
2. -1.2mv
3. 0mv
4. -1.2mv
5. -1.2mv

6. 0mv
7. 4.6mv
8. 0mv
9. 12.9mv
10. 0mv

Any help would be greatly appreciated



Deke609

  • Guest
Reply #1 on: May 29, 2020, 01:49:17 AM
Three easy things to check:

(1) check that the fuse is (a) inserted in the correct position (the lowest one; the upper position is just a storage space for an extra fuse), and (b) not blown;

(2) make sure your meter is set to measure DC volts (V with a flat and dashed line), NOT AC volts (V with a wavy line); and

(3) make sure that the tubes are inserted and the amp is powered on.

cheers, Derek


Offline jamesondrums

  • Jr. Member
  • **
    • Posts: 25
Reply #2 on: May 29, 2020, 02:54:35 AM
Checked all those off the list, same problem :/


Deke609

  • Guest
Reply #3 on: May 29, 2020, 03:01:29 AM
You could measure incoming AC voltage at the IEC inlet -- between Live and Neutral.  And then do the same thing at the switch. If you've got line voltage at the IEC inlet, but nothing at the switch, you may have melted the switch.

cheers, Derek


Offline jamesondrums

  • Jr. Member
  • **
    • Posts: 25
Reply #4 on: May 29, 2020, 03:40:21 AM
That seems to be working fine as well. I went through and checked all my wiring with the manual and checked my joints. All looks okay to my untrained eye haha.

- James


Offline jamesondrums

  • Jr. Member
  • **
    • Posts: 25
Reply #5 on: May 29, 2020, 03:56:57 AM
One thing I did do that I am now remembering is: plug the bigger tube in the wrong direction and then powered it on during the "glow test" I noticed it, fixed it, and then it started glowing. Could that have done anything?


Offline jamesondrums

  • Jr. Member
  • **
    • Posts: 25
Reply #6 on: May 29, 2020, 04:27:58 AM
And here's a picture of it just in case this helps.


Offline Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 19757
Reply #7 on: May 29, 2020, 05:40:52 AM
Is your meter set on DC voltage?  If it's set to AC, you will get weird readings.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline jamesondrums

  • Jr. Member
  • **
    • Posts: 25
Reply #8 on: May 29, 2020, 05:45:59 AM
It is set to DC. And the LED's are not lighting (unless they are super super dim and I am just not seeing it). I went through and checked my joints and add more solder to questionable ones as well.


Offline jamesondrums

  • Jr. Member
  • **
    • Posts: 25
Reply #9 on: May 29, 2020, 06:22:04 AM
Made a mistake on my first post, everything is reading at V not mV


Offline Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 19757
Reply #10 on: May 29, 2020, 06:24:28 AM
What is the AC voltage between 18 and 19?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline jamesondrums

  • Jr. Member
  • **
    • Posts: 25
Reply #11 on: May 29, 2020, 06:54:47 AM
I'm getting 172.6V between 18 and 19


Offline Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 19757
Reply #12 on: May 29, 2020, 07:14:53 AM
DC voltage between 20 and 21?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline jamesondrums

  • Jr. Member
  • **
    • Posts: 25
Reply #13 on: May 29, 2020, 07:20:36 AM
I'm getting -.89V DC


Deke609

  • Guest
Reply #14 on: May 29, 2020, 07:37:54 AM
It looks like you've got one diode of each diode pair going the wrong direction (one pair between transformer and terminal strip, the other on the outside of the terminal strip). The silver bands of each pair should be facing opposite directions. See pages 38-39 of the manual.

cheers, Derek


Pages: 1 2   Go Up
« previous next »