Mainline Resistance Question [solved]

[isldkid]

Sorry guys please disregard my last post I hit the wrong button.
Just did the resistance and voltage checks on my just completed Maineline, and have some weird readings.
Ohm readings on terminal:
1. 39.8
2.   0
3.   0
4.   0
5. 39.9
6-10. 0
11. 0
12. -
13. 0
14. -
15. 220
16. 0
17. -
18.0
19. 218?
20. 3 meg?
21. 0
22. 218?
23. 0
24.-
25. 220
26. 0
30. 1 meg?

Voltage readings all DC
Should read.              Measured
275.                          277
6.3.                           6.325
275.                          276
275.                          275.6
Berg B
220.                          154?
Berg A.                     
220.                          272

Note: All 6000 LEDs measure 274 volts DC and are lit except two LEDs on on the C4S board above the C tube socket on the "B" side of the C4S board the two LEDs are not lit and measures only 153 volts DC. Also switched out the 12au7 with the same results.

Any and all help on this matter would be appreciated.

Thanks and regards,
FC
 

[isldkid]

Ok pulled off both c4s boards also the regulater board, will check all three boards for correct wiring and switch c4s boards to see if trouble follows the boards.
Will report back results tomorrow.
FC

[Paul Birkeland]

Can you post the terminal numbers where the voltage issues are?  (something like 6.325V where there should be 6.3V is not worth mentioning)

[isldkid]

Paul, thank you for your reply, will try to get back with the terminals numbers and voltages after I check wiring  on the boards and assembly.

FC

[isldkid]

Paul, ok pulled out both C4S boards and check and compared side C (the side with the low voltage reading on 1B ) against each other all components and wiring checks out good.
Checked the regulator board all components and wiring is good.

Switched the C4S boards and the problem with the low voltage on terminalred that 1A still remained on board closer to tube C which should read 220vdc but reads 147vdc,  side A should also read 220vdc but reads 272vdc.

The regulator board's voltage checks out good with the exception of the B side Berg that reads 147vdc instead of the correct 220vdc. Side a Berg should also read 220vdc but I read 272vdc.

Let me also add that after I first applied power power to the Mainliner I discovered that two 100 ohm resistors were switched so I corrected that.

The all resistance checks out ok.

Please let me know if you need more info.
Thank you,
FC

[Paul Joppa]

Looks to me like it may be the tubes - swap tubes and see if the wrong voltage moves with the tube.

If so, I'd give the high-voltage tube a few (dozen?) hours to see if it settles it.

[isldkid]

Paul, switched out the tubes and voltages changed however the voltages on the C4S board  closer to tube C on average remained Lower.
Will see how it sounds and report results.
Thank you for the help.
FC

[Paul Birkeland]

How are your Kreg voltages? 

What happens if you run the Mainline w/o the 12AU7?

Your regulator is essentially not working, this could happen if if the Kreg or +Reg wires happen to be switched.

-PB

[isldkid]

Paul B, You may have addressed my problems here as after PJ's recommendation on switching the hi- voltage tubes (results are in my last reply) I adjusted the bias voltages, I was successful in adjusting both to 145, however the trimmer's adjustments were switched on the regulater board.
I might not be able to do any more work on the Mainline until later tonight, as for today my brother in law needs help tuning his "65" E -Type, and later go fly my U-Control "stunt" planes.
Thanks to the two Paul's for their help, I truly appreciate it.  FC.

[isldkid]

P.B., ok was finally able to get back to my mainline trouble shoot.
Kreg voltages with 12au7 plugged in:
A kreg 2 vdc
B kreg 23vdc

Kreg voltages without 12au7:
A kreg 1 vdc
B kreg 1 vdc

Would switched wires on kreg and reg also cause tube bias adjustment to reverse?
Thanks, FC

[isldkid]

Went through all wiring again for both C4S and regulator boards, everything checked out except for a broken lead that went to 16u.
Repaired the lead, and took a voltage check, all voltages looked good with the exception of unbalance voltages that switched sides when the high voltage tubes were moved.
PJ pointed this out and stated that it might take about 50 or so hours for the tubes to stabilize.
Have about 4 hours on the Mainline now, had to reset tube bias a couple times, but the amp is now sounding pretty good.
Listening through an HD-800 with Doc's Hybrid Anax 2 mod, unbalanced high impedance.
Thanks again to both Pauls for their help, I appreciate it.
FC

[Paul Birkeland]

Ah, most excellent, let us know how you like the amp!

[isldkid]

Paul, having had the privilege of listening to a crack speedball amp for awhile before building the mainline I felt that the upgraded crack sounded very good and a good basis for this comparison.
Well happy to report that after only about 35 to 40 hours of run in, the mainline is showing that it 's presentation, is more refined in handling mid and high frequency's transients without sounding strained, the low end has tighten up to where it has excellent impact and detail.
Just got a Justin Essig built balanced cable for the HD- 800 so will be listening to the mainline in the balanced mode now.
Thank you Bottlehead for another fine product and the excellent support.
FC

[Doc B.]

Thanks Francis! That's exactly how I would describe the sound of Mainline.

[adamct]

Francis,

I'm psyched that you got your HD800 cable from Justin. I love his work. If its not too much effort, would you mind posting a picture of the cable (might as well throw in a picture of the Mainline, too!)?

Best regards,
Adam