No sound, no tubes lighting up - did resistance checks

drewhaynes · 6432

0 Members and 1 Guest are viewing this topic.

Offline drewhaynes

  • Full Member
  • ***
    • Posts: 60
Reply #15 on: August 26, 2017, 12:48:26 PM
What... the... "fudge". It legitimately looks like those 2 joints were never soldered. For one, you have a ridiculous eye. And for two... I don't know how the amp actually worked originally. I'm going to solder those up tonight and see what happens. My mind is a little bit blown right now. :|



Offline fullheadofnothing

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 1487
  • A noble spirit embiggens the smallest man
Reply #16 on: August 26, 2017, 12:56:05 PM
It would work because it had enough of a physical connection to conduct. Then as the amp got jostled around in regular handling, the connection worked its way loose and could no longer conduct.

Joshua Harris

I Write the Manuals That Make The Whole World Sing
Kit Packer Emeritus


Offline drewhaynes

  • Full Member
  • ***
    • Posts: 60
Reply #17 on: August 26, 2017, 01:57:26 PM
Just resoldered B7 and B8... still not getting any tubes lighting up. Where should I go from here? Can anyone post the voltage tests I need to be doing at different points?



Offline fullheadofnothing

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 1487
  • A noble spirit embiggens the smallest man
Reply #18 on: August 26, 2017, 02:03:04 PM
What is the AC voltage between b7 and b8

Joshua Harris

I Write the Manuals That Make The Whole World Sing
Kit Packer Emeritus


Offline drewhaynes

  • Full Member
  • ***
    • Posts: 60
Reply #19 on: August 26, 2017, 02:05:51 PM
Zero volts from B7 to B8



Offline fullheadofnothing

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 1487
  • A noble spirit embiggens the smallest man
Reply #20 on: August 26, 2017, 02:10:58 PM
there must be a fault in a wire between one of those terminals and your power transformer. Check continuty/resistance of those wires.

Joshua Harris

I Write the Manuals That Make The Whole World Sing
Kit Packer Emeritus


Offline drewhaynes

  • Full Member
  • ***
    • Posts: 60
Reply #21 on: August 26, 2017, 02:11:55 PM
I'm sorry.. I'm a little new to this... where should I be checking specifically?



Offline fullheadofnothing

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 1487
  • A noble spirit embiggens the smallest man
Reply #22 on: August 26, 2017, 02:17:25 PM
There are twisted wires

They connect the power transformer

Where your voltage is correct

To your tube socket

Where it is not

The problem must be in one of those wires.

Wires have very low resistance. Measure the resistance between the socket and the transformer.

I am now logging off for the night.

Joshua Harris

I Write the Manuals That Make The Whole World Sing
Kit Packer Emeritus


Offline drewhaynes

  • Full Member
  • ***
    • Posts: 60
Reply #23 on: August 26, 2017, 02:32:56 PM
Unless my multimeter is just jacked... since soldering B7 and B8... I'm now seeing zero volts at the plug right where power comes in, as well as on the top two adjacent posts on the transformer where I was initially instructed to test. Not sure what to do from here...



Offline drewhaynes

  • Full Member
  • ***
    • Posts: 60
Reply #24 on: August 27, 2017, 05:15:22 AM
So... bigger issue maybe? I noted last night that I was no longer getting voltage readings after resoldering B7 and B8... turns out, that wall outlet is no longer working at all - cell phone chargers and things like that are getting no power there. I'm hesitant to try the amp on another outlet now... no breakers in the garage are tripped.



Offline Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 19772
Reply #25 on: August 27, 2017, 06:50:56 AM
That isn't a problem with the amp, I would plug it into a different outlet.  An outlet in the US will deliver 15A at 120V.  The Crack fuse will pop when you get over 1A of current draw.


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline drewhaynes

  • Full Member
  • ***
    • Posts: 60
Reply #26 on: August 27, 2017, 08:34:47 AM
Sorry, I realize that the outlet is the problem, I just didn't know if I shorted something in the amp that caused it to trip something. I'll test again shortly.



Offline drewhaynes

  • Full Member
  • ***
    • Posts: 60
Reply #27 on: August 27, 2017, 09:25:58 AM
These two.

Ok, update... I fixed the outlet and I'm now reading 120v at the posts where the 120V plug enters, as well as the posts on the switch, but I am now reading 0V-AC at the two adjacent terminals on the transformer itself, whereas prior to soldering B7 and B8 I was reading 120V at those terminals as well.

Does that give us any useful info?

Again, thank you guys SO MUCH for helping... I'm hoping I can resurrect this thing after years of no use. My only other amp is an O2, and it may be faulty memory, but I still have dreams of the Crack + HD650 destroying what the O2 can do with HD650/HE400/D2000!



Offline Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
    • Posts: 19772
Reply #28 on: August 27, 2017, 09:43:36 AM
Ok, update... I fixed the outlet and I'm now reading 120v at the posts where the 120V plug enters, as well as the posts on the switch, but I am now reading 0V-AC at the two adjacent terminals on the transformer itself, whereas prior to soldering B7 and B8 I was reading 120V at those terminals as well.
Test the voltage between L and N terminals on the IEC power entry module.

Test the AC voltage from N to each side of the power switch with the power switch on.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline drewhaynes

  • Full Member
  • ***
    • Posts: 60
Reply #29 on: August 27, 2017, 09:58:18 AM
I just messed around with a few things and I am now back to reading 120V at the top 2 adjacent terminals on the transformer. I tested the wires that run from the top RIGHT 2 adjacent transformer terminals that run from the transformer to the B7 and B8... I measured 0 or near 0 ohms resistance across these wires, and I measured ~6V from the centermost TOP RIGHT 2 terminals on the transformer to B7 and B8. I can take pics of the terminals I'm referring to if that helps.