Help! Mistakes were made...Assembly of Crack Amp Kit [resolved]

zaramon · 3678

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Offline zaramon

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First mistake I made is I used lead free solder with silver bearing rosin core. After completing steps up to page 23, I attempted to "Clip the black lead of your Digital MultiMeter to N on the IEC inlet. Clip the red lead of your DMM to L on the IEC inlet.", but when I measured the voltage, I was only getting 1.2V with the custom power cord and 5.2V with the provided stock power cable.  I felt like my solder connections were solid so I likely made mistake #2 when I continued the assembly from the "if voltage is less than 115V" (which mine certainly was) I followed all of the steps for that section and on page 29 I re-ran the test and now get 7.2V with the standard power cable so it did increase, but not by much. When I ran the Secondary Power Transformer test using terminal seven and terminal 9, I get zero voltage and it doesn't change if I turn the switch on or off for this check. I'll include some pictures, but if someone could help me, I'm stuck right now and not sure what to do next. Could it be my solder in which case I need to take it all apart back to the beginning? I'll wait to hear back from someone before going down that road. I have a link to some pictures I took, but this forum is not letting me share external links. Is there any other way for me to share some of the pics I have taken?
« Last Edit: October 14, 2022, 02:21:29 PM by Paul Birkeland »



Offline Paul Birkeland

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Reply #1 on: October 03, 2022, 05:37:07 AM
Can you clip your meter onto the amp as directed on page 23 of the manual and upload a picture of your measurement?

Is the fuse installed? In the correct position?

I would definitely throw away the solder that you have and get some leaded solder.  The lead free stuff isn't going to hurt anything, but it's very difficult to work with.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline zaramon

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Reply #2 on: October 03, 2022, 07:10:35 AM
Good afternoon and thank you for your assistance. The fuse is installed correctly as best I can tell it doesn't matter which direction the tube ends face and they are making contact to the connectors in the bottom of the switch. How can I share images with you? The forum doesn't want to allow my external URL. I have pictures of the requested voltage test. Can you piece this together? h++ps://photos.app.goo.gl/KsWtm6FV6TRumb2y9
The last picture with the DMM is the one requested I believe.



Offline Paul Birkeland

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Reply #3 on: October 03, 2022, 10:40:43 AM
OK, it's good to see that your meter is setup correctly.  If you shove the probes into your wall socket, do you see 120V?  How about if you shove the probes into the power cord? 

The fuse goes into the clip on the holder, not the square tunnel, and it's somewhat common for this to give you 0V at those terminals.

Either way, getting wall outlet and power cord readings will be helpful.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline zaramon

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Reply #4 on: October 03, 2022, 11:55:29 AM
Thank you, yes, the fuse is in correctly based on your description. I have tested both power cords and the wall outlet and they are all around 115V when tested directly.



Offline Paul Birkeland

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Reply #5 on: October 03, 2022, 01:19:45 PM
Leave one meter clamp on the N terminal of the IEC power entry module, then touch the other probe to the metal bar across from the L and N terminals and let us know what AC voltage you see there.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline zaramon

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Reply #6 on: October 03, 2022, 05:01:08 PM
I uploaded a few more pics, my voltage is still very low when connecting the N + L terminals, only getting a little over 3V which is slightly less than earlier today. One thing I did notice, does the orientation of the power switch matter? The instructions say to mount with the . or 1 side closest to the chassis, so that is what I did, however, moving the switch to the side with the o on it is powering the device on. Does that sound fine? I uploaded a pic of the power button called powerbutton.jpg on the same share from the previous message.



Offline Paul Birkeland

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Reply #7 on: October 03, 2022, 06:42:11 PM
Leave one meter clamp on the N terminal of the IEC power entry module, then touch the other probe to the metal bar across from the L and N terminals and let us know what AC voltage you see there.

In your pictures this area of metal actually says L by it.

There is no concern about the power switch at this juncture since you aren't getting your incoming AC line voltage, so don't worry about that just yet.
« Last Edit: October 03, 2022, 06:43:42 PM by Paul Birkeland »

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline zaramon

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Reply #8 on: October 04, 2022, 03:52:07 AM
Ok, I see what you meant, I misunderstood. Please see the most recent 2 pictures on the share I posted previously. One pic shows without the second lead touching the bar @ ~ 2.5V and second pic shows the second lead touching the metal bar across from the N + L terminal showing ~ 3.0V, so just a slight amount higher. Any thoughts?



Offline Paul Birkeland

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Reply #9 on: October 04, 2022, 04:07:38 AM
Can you retake that measurement but slip the clamps off the meter and just use the poky probes?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline zaramon

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Reply #10 on: October 04, 2022, 05:16:54 AM
Sure, I couldn't take a picture needing to use both hands, but I'm getting around 2V.



Offline Paul Birkeland

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Reply #11 on: October 04, 2022, 05:41:35 AM
I would try a different power cord.  These are commonly found on things like printers, monitors, etc.  This could just be a pin fitment issue with the current cord.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline zaramon

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Reply #12 on: October 04, 2022, 06:48:08 AM
I have a beefy powercord for my pc that I used with seemingly good connection, but still got the same/similar results. Any other thoughts or ways to break it down to basic components to test like the switch or fuse only?



Offline Paul Birkeland

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Reply #13 on: October 04, 2022, 07:59:53 AM
Again, it's not the switch, nor is it the fuse.  You can pull the switch out and toss it to the side and it won't make any difference to the incoming voltage and the fuse is after the metal strip across from the two solder lugs. The power cord has a hot and a neutral connection that carry the incoming line voltage, and those mate up to two poky bits inside the IEC receptacle, and that is what we are attempting to measure.

What I would do next is to leave the power cord plugged into the amp but pull it from the wall.  Set your meter to DC resistance and put one probe on one of the flat metal pins on the power cord that plugs into the wall, then touch L and N with the other meter probe to see if you get a 0 ohm reading, then repeat that for the other metal pin.  You should get 0 ohms between each flat pin on the power cord and one of the metal bits on the IEC power entry module.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline zaramon

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Reply #14 on: October 04, 2022, 09:42:38 AM
Yes, sir, getting a zero reading when switching to DC and performing those tests.