Jimmy's 400 Rev D in for Warranty

[derek92994]

The frustration continues...got a blizzard comin, all my wells tucked in for a 3 day storm if it gets that bad. 9- 20 Inches of snow and 60 mph winds....this should be fun.

Jut a slight movement of the upper right corner of the board....

Good luck Lee, Hope you and Jani are ok

 

[laatsch55]

Update....

After shorting out a low voltage regulator TO-220, and rebuilding the entire low voltage section, I am back on the original problem.......probe slip...

 

[laatsch55]

Good luck Lee, Hope you and Jani are ok

We are just great Darc!!

 

[laatsch55]

Joe, do I isolate the base drives in a quasi D the same way I would on a full comp?

 

[Gepetto]

Hi Lee
Please clarify your question a bit more so I can properly answer your question.

 

[laatsch55]

Desolder pad 3, 6 and 9, and add the resistors....

 

[Gepetto]

Desolder pad 3, 6 and 9, and add the resistors....

I should write that up. Give me a bit and I will commit it to Word so I can just cut-paste

 

[laatsch55]

K...

 

[Gepetto]

Preserved for posterity now.

Control board debug instructions

These are quick checks you can perform on your control board to ensure it is regulating properly.

Quasi-Comp Configuration, all PCB artwork revisions

• Pad references that follow will include L or R and will depend on the channel you are testing. The L an R are left off of Pad and component references for simplicity.
• Detach and tape off wires going to Pads 9, 8, 6, 4, and 3.
• Tack a jumper wire between Pad 3 and 12.
• Tack a jumper wire between Pad 8 and 6.
• Tack a 47 ohm 1/2W resistor between Pads 9 and 6.
• Tack a second 47 ohm 1/2W resistor between Pads 4 and 6.
• Bring up on DBT and Variac and ensure that the output on Pad 6 is zero or no more than 15 mV.
• Check that you have B+ on Pad 11.
• Check that you have B- on Pad 12
• Ensure that the voltage across each of the 47 ohm 1/2W resistors is less than 2V and the voltage on the 47 ohm 1/2W resistor tacked between Pads 9 and 6 varies as you adjust the bias potentiometer.
• If all good on the control board search for your problem on the backplane or backwall.
• If not all good on the control board, use this configuration to debug what is wrong with the control board.

Full-Comp Configuration, PCB artwork Revision D, E and G1

• This set of instructions assumes you have the White Oak Audio Backplane Kit installed.
• Pad references that follow will include L or R and will depend on the channel you are testing. The L an R are left off of Pad and component references for simplicity.
• Detach and tape off wires going to Pads 9, 8, 6, 4, and 3.
• Tack a jumper wire between Pad 8 and 6.
• Tack a 47 ohm 1/2W resistor between Pads 9 and 6.
• Tack a second 47 ohm 1/2W resistor between Pads PNP and 6.
• Bring up on DBT and Variac and ensure that the output on Pad 6 is zero or no more than 15 mV.
• Check that you have B+ on Pad 11.
• Check that you have B- on Pad 12
• Ensure that the voltage across each of the 47 ohm 1/2W resistors is less than 2V and the voltage on each 47 ohm 1/2W resistor varies as you adjust the bias potentiometer.
• If all good on the control board search for your problem on the backplane or backwall.
• If not all good on the control board, use this configuration to debug what is wrong with the control board.

 

[laatsch55]

Thank you Joe....

 

[laatsch55]

Did you put this in the WOPL Archives Joe?

 

[derek92994]

Electron Herders at their finest, love this stuff! (Even though most of it goes over my head )

 

[laatsch55]

Mine too...

 

[derek92994]

I would read his post in full 3 times then follow step by step. Variac? Dim bulb? Eh?

 

[laatsch55]

Always, till the high amp draws are gone..

 

[mlucitt]

Then we plug in some music and get some proper high amp draws...

 

[Gepetto]

Did you put this in the WOPL Archives Joe?

I can Lee

And did, started a new thread in the Archives.

 

[laatsch55]

Thank you Sir Joe!!

 

[laatsch55]

Jumpered as in the directions..

 

[laatsch55]

Measurements

Left channel
Plus lead on 6 neg lead on ground----------40mv
Plus lead on 9, neg lead on 6--------------+.566vdc
Plus lead on 4, neg lead on 6 ------------ -.218vdc
Adjustment range on pad 9 to pad 6 47 ohm is +.594 vdc to +.841vdc

Right channel
Plus Lead on 6, neg lead on ground----------36 mv
Plus lead on 9, neg lead on 6--------------- +.571vdc
Plus lead on 4, neg lead on 6--------------- -.238vdc
Adjustment range on pad 9 to pad 6 47 ohm is + .572 vdc to + .813 vdc