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need help troubleshooting--voltages are off(eek) (Read 8063 times)
rogerfederer
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need help troubleshooting--voltages are off(eek)
02/06/15 at 21:54:01
 
i did a build using rev 9 20111.  

i have done the CCE/hazen mod and the false center tap (using the new edcors).  the tubes do light up.  haven't tried it with a source and speakers.

here are the voltages i'm getting (targets in parens):
A   434                                 (346 +/- 10)
B  409                                  (309 +/- 10)
C  .5 mV                               (10.25 +/- 2)
D  3.5 & 4.5mV [left to right] (2.6 +/- 0.5)

see p.11 for the test points: http://www.decware.com/newsite/SE84CDIYINSTRUCTIONS.pdf

i have a decent multimeter (a tenma, with autoranging) so i don't think that is the culprit.

i'd love any ideas re what part of the board i should be starting with Smiley
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rogerfederer
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Re: need help troubleshooting--voltages are off(eek)
Reply #1 - 02/06/15 at 21:55:28
 
more pics
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rogerfederer
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Re: need help troubleshooting--voltages are off(eek)
Reply #2 - 02/06/15 at 22:09:19
 
more
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rogerfederer
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Re: need help troubleshooting--voltages are off(eek)
Reply #3 - 02/06/15 at 22:12:39
 
last one
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rogerfederer
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Re: need help troubleshooting--voltages are off(eek)
Reply #4 - 02/07/15 at 14:49:59
 
A local friend comments I'm missing a bunch of jumpers.  Will take a look at that.
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mboxler
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Re: need help troubleshooting--voltages are off(eek)
Reply #5 - 02/07/15 at 15:29:09
 
Also...your output transformers are not wired correctly.  The blue inputs
should be connected to the R WHITE and L WHITE.  I assume you are
connecting your speakers binding posts directly to the output
transformers, hence the R BLU, R BLK, L BLK and L BLU will not be used.

Good luck!

Mike

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rogerfederer
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Re: need help troubleshooting--voltages are off(eek)
Reply #6 - 02/07/15 at 17:24:32
 
Hey mike,

Thanks, will try that.  Gets confusing using an older board and newer trafos.

So do need to wire up all the jumpers?

Doug
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mboxler
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Re: need help troubleshooting--voltages are off(eek)
Reply #7 - 02/07/15 at 19:37:41
 
Yep!  Should be J1 thru J6.

I also noticed black caps (?) hear the output tubes.
What are they for?

Mike
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rogerfederer
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Re: need help troubleshooting--voltages are off(eek)
Reply #8 - 02/07/15 at 19:50:04
 
the black caps are for the CCE/hazen mod; its not built into this board AFAIK

so the red leads from the output trafos are in the right place?

thanks Smiley
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mboxler
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Re: need help troubleshooting--voltages are off(eek)
Reply #9 - 02/07/15 at 20:14:43
 
The two .1uf caps that you already have next to the output tubes
are the CCE Mod caps.  You can remove the black ones, as they are now parallel to the white ones (they both should connect pins 3 and 6).  

The red wires to the output transformers are correct (although I can't tell if the left and right are correct).   Just connect the blue wires to the WHITE holes.

The newest board has been changed to reflect the Edcor wire colors.  I have the same board you have...it is confusing.

Mike

Here'e one of mine.  Some components are soldered on the other side.

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rogerfederer
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Re: need help troubleshooting--voltages are off(eek)
Reply #10 - 02/07/15 at 20:47:32
 
hey sharp eyes!  i guess the hazen mod was announced in 09 so it logically should be in a board dated 2011

have the jumpers in and the blue wires moved.  will take out the extra caps and check voltages again Roll Eyes
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rogerfederer
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Re: need help troubleshooting--voltages are off(eek)
Reply #11 - 02/07/15 at 21:03:39
 
and hallelujah!  we have an amp Grin

350.7
313
9.78
2.63  2.68

so all within tolerances

now to test it with a source and some speakers!

mike, can't thank you enough.  will report on the next steps...
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litefootdan
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Re: need help troubleshooting--voltages are off(eek)
Reply #12 - 02/07/15 at 23:05:16
 
Glad your getting proper voltages!!!  The kit should sound real nice.  Please keep us informed of your setup and how it sounds.  I ended up building two of these kits and running them as monoblocks.  I like them very much but haven't found the perfect speakers for them.  I'm sure the time will come....    

Keen eye Mike.  Excellent solutions.  
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Ortofon 2M Bronze | Merrillized AR "The Turntable" | ZP 2 | SE84UFO25 | HDT | Jensen Alnico 15's on the low "OB"
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rogerfederer
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Posts: 12
Re: need help troubleshooting--voltages are off(eek)
Reply #13 - 02/23/15 at 19:08:25
 
now it is running!  when i first tried to run it i had no left channel.  turns out i had wired the volume pot wrong and then broke it while fixing the wiring.  so ordered an alps from parts connexion, which took a while to arrive.  then my voltages were off a bit (1st "D" point).  i improved my grounding and rechecked my soldering.  

that voltage is still a bit high but i have 2 channels and it sounds great!  i decided to run it for a while and will revisit the voltages in a bit.

thanks for the advice and support Grin
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