Help with early voltage test of Crack

oz · 1575

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Offline oz

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on: July 05, 2018, 05:11:56 PM
Hi everyone,

I have run into a problem in one of the early voltage checks with my crack. I'm building it to the 118 volt specification (more than 115 less than 130) and I'm not getting any voltage on terminals 7/9 or 11/12 on the PT 10 Transformer. Could anyone give some advice on what may be wrong? I checked the resistance of the rocker switch and I'm getting overloaded, however I don't think I melted it when soldering it. I did end up ordering a new one just in case. Does my soldering need to be redone?

Thanks




Offline Paul Birkeland

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Reply #1 on: July 06, 2018, 07:26:31 AM
A few things:

1.  You're missing the four #8 nuts that hold the power transformer onto the chassis.  These aren't optional.
2.  The green wire going to A9 has way, way too much jacket stripped off.  When we say 1/4", we mean 1/4", and you should insert the 1/4" of bare wire through the hole in the socket pin, then bend it up to rest against the socket pin, then solder.
3.  The other green wire is not properly installed.
4.  The ground lug by the IEC power entry module is not all the way soldered.

These are the marks of someone who is in a huge hurry.

To be able to measure power transformer voltages, you need to have the fuse installed and the power switch on. 

We have the "Power Transformer Secondary Test" immediately following the wiring of the primary so that you can know that your power transformer is working properly before moving on.  You've moved on and now added some complexity to diagnosing what's going on.

Having said all of this, what AC voltage do you have between power transformer terminals 16 and 18?

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline oz

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Reply #2 on: July 07, 2018, 02:51:20 AM
A few things:

1.  You're missing the four #8 nuts that hold the power transformer onto the chassis.  These aren't optional.
2.  The green wire going to A9 has way, way too much jacket stripped off.  When we say 1/4", we mean 1/4", and you should insert the 1/4" of bare wire through the hole in the socket pin, then bend it up to rest against the socket pin, then solder.
3.  The other green wire is not properly installed.
4.  The ground lug by the IEC power entry module is not all the way soldered.

These are the marks of someone who is in a huge hurry.

To be able to measure power transformer voltages, you need to have the fuse installed and the power switch on. 

We have the "Power Transformer Secondary Test" immediately following the wiring of the primary so that you can know that your power transformer is working properly before moving on.  You've moved on and now added some complexity to diagnosing what's going on.

Having said all of this, what AC voltage do you have between power transformer terminals 16 and 18?

-PB

Thanks for all the advice and some things I missed. I'll need to get back to you on the AC voltage between terminals 16 and 18.