Need Help again

[lth1]

Need help with my BeePre, again.  Someone head me in the right direction, all wires are secure.
 
Terminal Voltage (VDC) Actual VDC
1. 5 VDC 5.02 VDC
2. 90-110 70.3
4. 9.85 9.78
6. 146 +/- 145.7
10. 186 188.5
11. 146 +/- 186.4
15. 186 189.4
16. 5 4.92
17. 90-110 .09
19. 9.85 9.77
22. 213 215.3
25. 213 215.1
29. 6.8 6.54
30. 6.8 6.56
31. 13.6 13.37
34. 13.6 13.61
35. 6.8 6.77
36. 6.8 6.77
40. 213 215.8
43. 213 215.7
46. 213 215.7
C3 3.5-4.5 6.76
D3 3.5-4.5 6.53
C7 147 145.7
D7 147 186.5
C9 147 145.4
D9 147 184.8

 

[Paul Birkeland]

The B side C4S is not functioning.  Are all the LED's lit? 

 

[lth1]

No, the two leds towards the front are not lit.

 

[Paul Birkeland]

On that C4S board, what voltages do you have at IA, OA, IB, and OB?

I can tell by your voltages that the 300B under that C4S board is heating up and would otherwise work properly.

Your high regulated voltage tells me that the shunt regulator isn't functioning. 

One easy thing to try would be to remove the EL84 on the offending side to see if that restores C4S board operation.

-PB

 

[lth1]

          Left          Right

1A    188.3        187.6
0A    189.7        145.7
1B    189.7        145.7
0B    188.2        70.6

Removing left channel tube, no leds are lit.  With the tube in place the A side leds are lit, B side leds have never been lit.

 

[Paul Birkeland]

This most certainly nails it down to the C4S board.  As always, I'd start by reheating all the solder joints - especially the center leg of each MJE-5731A.

Next, you could measure resistances between each pair of transistor legs to check for shorts. 

 

[lth1]

No change, all solder joints resoldered, transistors legs check out, no shorts.

 

[Paul Birkeland]

Try swapping the C4S boards between the working and non-working side.

 

[lth1]

Paul, I swapped the C4S boards, both react the same only two leds lit, time now to advance to the filament regulator board.  I installed the working board into the non-working side, which is the RIGHT (error on my part) regulator board, and only two leds lit up.  This same problem has now occured on both sides of my BeePre.  The original just some how corrected itself, yes just out of the blue all four leds lit up and it is the only side working to date.  It does not look like it will happen this time.

I actually have three sets of the boards.  All three boards sets work in the left side. 

 

[Paul Birkeland]

OK, so we know there is an issue on the right side, and that it's not the PC boards.

The next thing to do is to remove the PC boards from the offending side and hit all your solder joints.  Also, take your needle nose pliers and gently tug on each wire and each component to be sure nothing is loose. 

I would guess that you have a loose wire or component in the high voltage power supply that is acting as a current limiter.

-PB

 

[lth1]

Thanks Paul for all of the help.  I am out of commision for awhile, let you know what happens with the BeePree.