failed High Voltage Power Test [resolved]

D

Dynakitbuilder

New member
previous tests were OK: Powerline = 123 vac.  Transformer secondary test:  page 30.  194 vac, 6.7, 6.7, 6.7.
Page 34, high voltage test: 0.00.  Checked fuse, OK. Reheated all connections from #s 7 & 8 on transformer forward.
 
Check that your meter is set to read DC voltage (two parallel lines, one dashed and one solid). The previous p. 30 tests were for AC.

cheers, Derek
 
Hmm. There's not a lot that can go wrong there. I'd double check the orientation of the diodes. If that's not it, posting some detailed pics of the trafo area from different angles might be a good idea.

cheers, Derek
 
I would post a photo of what you've built and be sure not to proceed with the rest of the build until this is resolved.
 
A few thoughts -

Test the meter's DC setting with a battery to be sure it's working OK in DC mode.

Carefully check each of the terminals from the power trans out to terminals 31 and 33 for correct wiring against the manual.

Measure resistance from terminal 31 to 33 and make sure that it is not super low, like near 0 ohms. Probably won't be, as likely you would have blown a fuse if it was.

If the wiring is all correct and nothing is shorted the .001VDC reading indicates that the high voltage is not getting all the way through the filter. Reflow all the joints from the power trans high voltage terminals to the final terminal strip of the power supply filter, where the DC voltage test terminals 31 and 33 are.





 
I would reflow some of your solder joints again, especially 37L.  The convex dome shape seen in one of your photos can indicate a cold solder joint in my experience. 
 
Found at least one problem; fuse blown, no AC volts.  I checked the fuse before starting the first checks and assumed it was fine since all the other tests were OK up until the high voltage tests.  Anyway, there has to be something wrong that blew the fuse, right? 
Thanks for all the suggestions - at least all the soldering has been done over twice.  It's my 4th kit to build in the last 12-18 months; I should be at least barely useful at that part by now...just ordered a couple fuses from the Queen.

Tom
 
If 36 and 35 are shorted together with the lead of the 22R resistor, you'll blow fuses.  If you have a diode backwards (you don't seem to), the fuse will blow.  If terminal 8 and 9 on the power transformer are shorted out by diode leads, you'll blow a fuse (also looks unlikely from your build).

Some higher resolution photos with some more light would be helpful.
 
If a lead from power transformer terminal 7 touches a lead from power transformer terminal 8 (on the UF4007s), then you'll short out the high voltage wiring.  To avoid this, pull a little tension into all the diodes at the terminal strips so they stay away from each other.
 
Separated the diodes, and did the correction @ 35 to 33.  Reheated all connections from 31 to 33U.
Got 24 VDC that slowly went down to 13 VDC +/-.
 

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Is your fuse blown?

You absolutely need to use more solder on those 3 lug strips, especially on the lower lugs.

What is the DC voltage between 37 and 39?
What is the DC voltage between 34 and 36?
What is the DC voltage between 31 and 33?
 
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