New Construction. Some issues solved. Some not. Need advice.

[harv-e]

I considered that.  It could be that the battery needs to be changed.  The meter is made in China and that might be a factor too.  And I noticed that the manual states the AC mains voltage at which the figures were obtained from the circuit board duirng testing.  I didn't check my wall voltage.  But if all the figures are low by the same percentage, doesn't that mean that they're all OK?  For instance, the voltages on the Left and Right boards may be low, but they're pretty close to one another. 

I'll change the battery tonight and post again, but after all, it's a $10 meter from Harbor Freight.

[Paul Birkeland]

IA and IB are regulated, as is the 6.3V supply on the power supply PC board.  When you put in a fresh battery, measure that 6.3V pad to be sure that the meter is working properly.

-PB

[harv-e]

New battery installed in meter.  Voltages seem worse!

Power Supply Board
T4/5 = 6.4     T6/7 = 95.5      6.3vdc pins measures 4.9vdc       275vdc pins measure 216vdc

LEFT Board      Kreg 1.02  breg 80.2  OB 78.8  OA 122.5  bA 0  1A 187
RIGHT Board    Kreg 0.83  breg 80.2  OB 79.4  OA 126.2  bA 0  1A 187

Harvey

[Paul Birkeland]

Hey Harvey,

With the amp on, put the black probe on the "-" pad on the 6.3V corner of the board, and the red probe on the "+" pad on that same corner, then see what that DC voltage is.

Though this may seem annoyingly redundant, any differences here will provide useful information.

-PB

[harv-e]

When I listed the voltages on the power supply, they were all taken directly from the pads on the board.

I compared the DC voltages with the neg lead on the pad with the negative lead on the chasis and they were the same.

Harvey

[Grainger49]

The voltage checks are typically from a point, terminal or PCB pad, to ground.  PB is asking you to measure from one PCB pad to another.  It just might be different.

[harv-e]

OK.  Maybe I'm not understanding.  The lower right hand corner of the power supply board, next the the nut on the screw, has a + and a - "pad" just under the 6.3vDC stencil.  I checked this voltage with the two probes from the meter.  Then moved the negative probe to pin 23 of the terminal strip, leaving the positive probe at the + on the power supply PC board.  These two voltages were the same. 

Is this what is being asked?

Harvey

[Grainger49]

That is good.  The measurement on the board says that it is producing the right voltage, the measurement to a ground lug says that the circuit is grounded as it should be.  (I'm assuming you are saying that the voltage is right.)

[harv-e]

Unfortunately, that's not true.  The voltages both read 5.1vDC, not 6.3vDC....regardless of where they are measured.

I will  borrow another meter from a friend and see if there is any difference in the readings.  Stay tuned......

[Paul Birkeland]

Do let us know about the other meter, getting anything that is lower than about 6.25V or higher than 6.35V is very suspicious there, and getting the same voltage with your black probe in the two different places tells us that your grounds are wired in.

On the other hand, if you do end up finding that you have that very low voltage there, you have have found the entire problem with your Eros (but good to double check before we go further).

-PB

[harv-e]

OK.  Borrowed a friends GB meter.  Here are the voltages with this meter.

Line 119.1
Power Supply:  T4/5 8.5vAC      T6/7 126.7vAC     6.3vDC measures 6.21 to pads (6.22 to ground pin 23)     275vAC measures 299vAC
LEFT Board      Kreg 1.1   breg 95.4   OB  93.2    OA  158.5     bA 0     1A 297
RIGHT Board    Kreg 1.1   breg 97.3   OB  96.6    OA  160.5     bA  0    1A 298

Hope this gives better information for you.

[harv-e]

Just a reminder about the underlying issue.  The music sound and quality is terrific.  But there is an underlying low frequency motorboating putt-putt noise coming out of both speakers that can be heard during quiet music passages and even with the turntable unplugged.  Switching the tubes and tapping them has no effect.

Just a reminder about what this is all about.

[Paul Birkeland]

We are getting somewhere now!

Measure the pads on the power supply board, specifically IA/IB, OA/OB, and Kreg. 

-PB

[harv-e]

There is a smaller board under the power supply board with the following markings and voltages (I cannot find OA OB or IA IB pads on this board:

LEFT A side:    bA 0    breg 1   +reg 1   Kreg 9.0
RIGHT B side:  bB 0    breg 1   +reg 1   Kreg 8.9

[Paul Birkeland]

Yes, sorry, the regulator board just under the power supply board.

This board is the same board placed up front over the EF86 tubes, it has the "IA", "OA", "IB", and "OB" pads in all the same places.

breg and +reg can't be 1 with everything else you've told us, perhaps you need to turn the range up on the meter?

-PB