speedball upgrade voltage check issue

[sruo]

Hi, after receiving a missing resister, I finally finished speedball upgrade.
However, I have following voltage check result -

Terminal Voltage (VDC)  reference/my value
1 75/0
2 170/195
3 0/0
4 170/195
5 75/80
6 0/0
7 100/75
8 0/0
9 100/120
10 0/0
11 0/0
12 0/0
13 170/195
14 00
15 185/210
19 0/75
21 206/220

A1 75/80
A2 0
A3 1.56/1.6
A4 0/0
A5 0/0
A6 75/0
A7 0/0
A8 1.56/0.4
A9 0/0

B1 75/0
B2 170/200
B3 100/75
B4 75/80
B5 170/200
B6 100/120
B7 0/0
B8 0/0

There is NO voltage from 1,A6 and B1.  Could it be 12AU7 tube issue?
Also, all HLMP-6000 LED light up correctly except D1(the one on board A that close to MJE350) and A8.
I had my crack up and running for a week with no issue before the upgrade.

Any suggestions?

Thanks.

[Doc B.]

If the 12AU7 worked before you installed the upgrade, that is probably not the place to start looking for the problem. Check your 2N2907 and 2N2222 transistors to see if they are in the proper locations.

[Paul Birkeland]

If all the transistors are in place, I'd reheat the center joints on each of the MJE350's on the smaller green boards.

That particular board is not functioning, generally this is an issue with a solder joint or a transistor/LED that's out of position.

-PB

[sruo]

No luck.
Both 2N2907 and 2N2222 are in proper alignment with circuit board picture.
I also reheated all joins on board A and B.

Still same voltage result.

[Paul Birkeland]

Check the resistance between 3 and G of the offending board.

You may also want to actually pull out that board and really look at the bottom, just to be sure everything is well soldered.

Also, what is the voltage at the "I" pad?  It's possible that the "I" and "O" wires are reversed by accident.

-PB

[sruo]

Board A (offending one) R1 250 / R2 between 100 and 200 K.
O/0
I/190
B/190 C/0 E/190 (MJE350)
D1 and D2 all 4 joins /190 (HLMP-6000)
B and C and E /190 (2N2907)
R1 both joins /190
R2 190/0 where 0 is the ground side

Similar reading on board B as well except O/80 and middle (MJE350) /80

I recheck solder board A solder join via magnify glass.  Looks pretty clean to me. (see my prior attached picture)

Any thing I check further?

[Paul Birkeland]

It's still most likely the center leg of the MJE-350... (or it's in backwards, the writing faces away from the center of the PCB).

[Doc B.]

Yeah that looks like it might be the problem. The A board MJE350 is maybe in backwards?

[sruo]

You are right.  I put MJE350 backward on board A.
After desolder and resolder, now terminal 1 has 195 reading (same as terminal 2).
Did I busted board A?  From what I can see, new MJE350 solders are intack and not touching each other.

Thanks.

[Paul Birkeland]

Yeah, shoot an e-mail to replacementparts(at)bottlehead(dot)com and we can shoot you an extra board and parts to fix you right up.

-PB

[sruo]

Thanks.  Will send email to request replacement parts.
  no more peaceful sound for this long weekend then.

[sruo]

 
Just got the replacement board A (and parts) today. MJE350 is in correct orientation this time.
Still the voltage reading is NOT matching. (looks similar before replacing the new borad A)

1 75/195
2 170/195
3 0/0
4 170/195
5 75/80
6 0/0
7 100/190
8 0/0
9 100/120
10 0/0
11 0/0
12 0/0
13 170/195
14 0/0
15 185/210
16 x/0
17 x/0
18 x/75
19 0/75
20 206/0
21 x/220
22 x/0

A1 75/80
A2 0/0
A3 1.56/1.5
A4 0/0
A5 0/0
A6 75/195
A7 0/0
A8 1.56/12
A9 00

B1 75/195
B2 170/195
B3 100/195
B4 75/80
B5 170/195
B6 100/120
B7 /0
B8 /0

Please help!!!

[Paul Birkeland]

Are both halves of the 12AU7 glowing?  I'm guessing one of the LED's on the socket isn't lighting?  What voltage do you get if you remove that board and put the 22K resistor back?

(The voltage at terminal 1 is causing the rest of the voltage issues)

Do you have a different 12AU7 to try?

-PB

[Paul Joppa]

At A8 - bad LED, or backwards LED, or bad LED solder joint.

[sruo]

Are both halves of the 12AU7 glowing?  I'm guessing one of the LED's on the socket isn't lighting?  What voltage do you get if you remove that board and put the 22K resistor back?

(The voltage at terminal 1 is causing the rest of the voltage issues)

Do you have a different 12AU7 to try?

-PB

1. Looks both halves of 12AU7 glowing just very lightly. (Can only see glow in dark room.)
2. Attached a pic of LED.  Basically, board A and A8 is not lighted. All others looks good.
3. Do you know where I can buy another 12AU7 around bellevue/seattle?
4. Like to try out another 12AU7 before switching back to 22K resistor.

Thanks