Crack Voltage Check Problems

[Nocturnal]

Howdy I've recently finished building my Crack and did the resistance and voltage check today.  Resistance worked out fine but I've come across some problems with the voltage checks and wondered if anyone would be able to point me to where I might have messed up!

Terminal 11 should read 0 VDC .. I'm getting 80 VDC falling slowly to approx 45 VDC
A4 and A5 both should read 0 VDC .. I'm getting 75 VDC falling slowly to approx 45 VDC
B7 and B8 both should read 0 VDC .. I'm getting 75 VDC falling slowly to approx 45 VDC

Many thanks for any ideas in advance!

 

[Nocturnal]

Going through this step by step again for the fourth time and really don't understand, especially terminal 11 voltage as there is nothing soldered to terminal 11!  Where is that voltage coming from?

 

[Doc B]

It sounds like you might be missing a ground connection somewhere. Are you connecting the black test lead to terminal 12? I would suggest checking all of the solder joints to make sure nothing was missed.

 

[Nocturnal]

I have found one error .. on page 19 it says "Insert the red wire end through A5 and then A4, and solder both A4 and A5" .. I did this backwards .. going through A4 into A5 .. would that make a difference??

Yes using terminal 12 for the black test lead.

 

[Nocturnal]

Fixed it so wire goes through A5 and into A4.  Also found a poor solder on the centre pin of the 9 pin socket.  Still have the odd voltages.

Also rechecked all voltages and also get 75-80 VDC falling to 45 ish VDC on A9.  Sigh

 

[hasafraker]

if you can, take some hi-res pictures of your build, that will allow folks to look at it, maybe someone can spot something that might not be obvious to you since you've been staring at it for two days. Fresh eyes might help.

 

[Nocturnal]

if you can, take some hi-res pictures of your build, that will allow folks to look at it, maybe someone can spot something that might not be obvious to you since you've been staring at it for two days. Fresh eyes might help.

  Not to mention it's my first kit and first soldering job, so all help in gratefully accepted   Here are some photos .. if anyone can spot anything or needs a different view .. please please let me know!  I couldn't upload the full sized images here so I stuck them in Flickr.

http://www.flickr.com/photos/58465568@N08/?saved=1

 

[Doc B]

I didn't spot anything obvious in the photos. I would suggest checking the connections on terminals 17 thru 22 next, and make sure the silver band orientation of all the UF4007 rectifiers are correct.

 

[hasafraker]

Your 9 pin socket doesn't look like it's wired correctly to me. Looking at pictures of the under side of my crack, it looks like you have pin 4 wired to ground? It could just be the picture, but it looks to me like the heater wire comes down to pint 5 and then connects to pin 4, but the black wire there looks like it runs to ground? If I'm right and pin 4 is wired to ground that wire should have been connected to the center pin of the socket and not to pin 4.

 

[lth1]

hasafraker, pin 4 does not connect to ground, one needs to enlarge the photos to actually determine this.

nocturnal, when soldering pins 4 & 5, the input wire can be attached 5 to 4, or 4 to 5, there is no proper sequence here.

Cordially,
Lee Hankins

 

[Nocturnal]

I didn't spot anything obvious in the photos. I would suggest checking the connections on terminals 17 thru 22 next, and make sure the silver band orientation of all the UF4007 rectifiers are correct.

 I re-heated and re-soldered 18-22 and still have the same results.  Checked silver bands on all the UF4007s and they're oriented correctly.

 

[hasafraker]

hmm well I took another look at the pictures, on my 27" monitor, and the small 9 pin socket still appears to be wired incorrectly, so unless I'm crazed, I would take a look at that. Pin 4 should only be connected to pin 5, it appears to me ...and the 4 other people that I've shown it too, that Pin 4 is wired to ground. I thought maybe that the insulation melted and lifted off the ground to the center wire giving the illusion that it was wired wrong but from the 3 photos provided, viewed as large as I can view them, it appears incorrect to me.

 

[Nocturnal]

hmm well I took another look at the pictures, on my 27" monitor, and the small 9 pin socket still appears to be wired incorrectly, so unless I'm crazed, I would take a look at that. Pin 4 should only be connected to pin 5, it appears to me ...and the 4 other people that I've shown it too, that Pin 4 is wired to ground. I thought maybe that the insulation melted and lifted off the ground to the center wire giving the illusion that it was wired wrong but from the 3 photos provided, viewed as large as I can view them, it appears incorrect to me.

  Actually the wire that goes through 5 then into 4 has a long end left on it (that I need to clip) and it makes it look like black wire comes down and connects to the long end .. it doesn't.

 

[hasafraker]

ahh well that would explain it then

 

[Nocturnal]

Left it for a week in complete frustration, then sat down to go through it again .. found the problem within 2 mins .. I'd looped the bare wire from terminal E of the IEC power entry socket through the safety ground lug but had never soldered it.  Soldered it and everything checked out.  Listening to it now and loving the sound!

 

[Doc B]

Well done! Taking a break from a tough dog and coming back fresh is one of my favorite ways to fix things.

 

[Grainger49]

I think after a while it becomes the forest vs. trees thing. 

Glad you found it.

 

[hasafraker]

congrats on finding it very satisfying to sort it out and get to do some listening enjoy it!