News:
October 22, 2021, 08:14:47 AM

Author Topic: eros tape shunt regulator voltage test  (Read 1871 times)

0 Members and 1 Guest are viewing this topic.

Offline mkontor

  • Jr. Member
  • **
  • Posts: 46
  • avid audiophile
    • noteperfect loudspeakers
eros tape shunt regulator voltage test
« on: August 17, 2013, 05:25:40 AM »
I am up to this part of the build.
On the B side of the board the 2 LED's do not light and I get 300VDC; the A side is fine (225VDC) and LED's glow.
I have double checked all the connections etc.
Any ideas anyone?
Cheers,
mike
NotePerfect MAESTRO speakers, Doge 6 & 8, Pioneer rt707, Cymer tube amps, Oracle Delphi/Origin Live motor & PSU, Origin Live Illustrious, Phantom Cables

Offline mkontor

  • Jr. Member
  • **
  • Posts: 46
  • avid audiophile
    • noteperfect loudspeakers
Re: eros tape shunt regulator voltage test
« Reply #1 on: August 17, 2013, 05:36:15 AM »
i removed the 12BH7 and both sides of the board measure 350VDC, which is correct as there's no draw from a tube.So I guess I have a faulty 12BH7...will have to dig up another one
NotePerfect MAESTRO speakers, Doge 6 & 8, Pioneer rt707, Cymer tube amps, Oracle Delphi/Origin Live motor & PSU, Origin Live Illustrious, Phantom Cables

Offline Grainger49

  • Hero Member
  • *****
  • Posts: 7175
Re: eros tape shunt regulator voltage test
« Reply #2 on: August 17, 2013, 06:58:40 AM »
Without the 12BH7 the circuit doesn't regulate, it will be high.

You are lucky, you have a working side to compare the non-working side with.  First just check that the components are the same.  I think this board is kind of Mirror Imaged so be careful.  If the components are good you need to check the solder joints.  The ones that are most problematic are the ones on the transistors.  Just reheat them touching the solder and the transistor lead.  Both get heated till it is liquid and let it cool again. 

Because these are so close together I'm not suggesting that you not add solder right now.

Check this and post back.
« Last Edit: August 18, 2013, 04:51:24 AM by Grainger49 »

Offline Paul Birkeland

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 15704
Re: eros tape shunt regulator voltage test
« Reply #3 on: August 17, 2013, 06:36:52 PM »
What are the Kreg voltages on each side of the PC board? 

No LED's lighting can mean a lot of things, I'd triple check that you have the 2N2907 transisors on that board, and not he 2N2222A.

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline mkontor

  • Jr. Member
  • **
  • Posts: 46
  • avid audiophile
    • noteperfect loudspeakers
Re: eros tape shunt regulator voltage test
« Reply #4 on: August 18, 2013, 04:08:07 AM »
t's all good, resoldered the board
NotePerfect MAESTRO speakers, Doge 6 & 8, Pioneer rt707, Cymer tube amps, Oracle Delphi/Origin Live motor & PSU, Origin Live Illustrious, Phantom Cables