Eros 2 Help 2

[adeep42]

Been moving along slowly and carefully since previous issue. Just completed build, Resistance checks are perfect. Some of the voltage checks seem to be out of the 10% +/- range, Particularly 1A and 1B.

1A  140
1B  272
OA  138
OB  132
OC  93
OD  97
OkA  95
OkB  98
OkC  1.39
OkD  .867

Your thoughts.

Thanks and best,

Alan

 

[Paul Birkeland]

IA and IB come from the regulator that's built on/above the D socket.  If you remove those blue wires from IA/IB on that main C4S board, what do you now see at +reg on the C4S board above the D socket?

It is possible that there's still an issue at the D socket that needs to be resolved.

-PB

 

[adeep42]

Good Morning Paul,

It's 7:45AM your time. It's okay with me if you don't get to this til Monday.

  A side +reg  196.5 VDC
  B side +reg  291.00 VDC 

 

[Paul Birkeland]

Yeah, at least one side of your regulator board isn't working again.  I would recheck your Kreg voltages and double check those D socket connections again.

 

[adeep42]

Just finished total check of D socket and Shunt Regulator Board. Now voltage at the MJE5731As is A @ 295, B @ 294.

 

[Paul Birkeland]

So now neither regulator is working properly.  Are all the tubes still glowing?  What voltage do you get across the 6.3V terminals on the power supply board?

 

[adeep42]

Tubes all glow.

Voltage is 6.3vDC.

LEDs on A side of shunt regulator light up and are steady. LEDs on B side flash several time and then go out.

 

[Paul Birkeland]

This is with the wires going to IA and IB on the front board disconnected right?

What are the Kreg voltages on the board above the D socket?

 

[adeep42]

NEW BALLGAME!

My mind is spinning. Keep going over everything touching up solders, etc.  Found a mistake. White wires from D socket went to the wrong kregs. Switched them. Reattached wires to IA and IB. Only 2 voltages now outside the range.

IA  110.4  ?
IB  218
OA  108.3  ?
OB  154
OC  94.9
OD  96.6
OkA 95
OkB 98
OkC 1.5
OkD .866

 

[Paul Birkeland]

With the Kreg wires properly installed, how did the regulator board check out before you hooked it back up to the front C4S board?

 

[adeep42]

A Side MJE5731A  220VDC
B Side                  177VDC-off by 15%

 

[Paul Birkeland]

OK, I would leave the IA/IB wires off the smaller C4S board and debug the shunt regulator.  What are its Kreg voltages?

 

[adeep42]

kreg A  3.21

kreg B    .625

 

[Paul Birkeland]

What's the voltage at the X terminal on the B side?

 

[adeep42]

175 vDC

 

[Paul Birkeland]

The one that's closer to the center of the long edge on the board, not the one by +reg.

 

[adeep42]

I don't see an X on that part of the board
.

 

[Paul Birkeland]

This?

 

[adeep42]

Sorry, it was obscured by the cap.

2.48 vDC

 

[Paul Birkeland]

If you have 2.5V (2.48 is close enough) on that X terminal on the B side but Kreg is 0.6V on the same half of the board, you most likely have a miswire from the Kreg terminal to the D socket, or an ungrounded grid (D2 and D7 are the grids).

When you said before that you got "good readings" in your shunt regulator test, what were those readings exactly? 

You seem to have about the same problem you had previously.  It might be a good idea to go over the solder joints on the board above the D socket again.