My First Phase Linear Restore- New Guy to the Forum

[laatsch55]

Mike, the red wire on the left backplane, coud we get a closeup of it?? For some reason that doesn't look right, can't tell though without it being clearer...

 

[laatsch55]

Geez Lee, we're thinking alike today.

Amen Doug!!!

 

[mjstriker]

LOVE THE BABB!!!!!

Did you run a straight edge on the standoffs on the backside to check for too long leads?? Do you have continuity between the backplane ground and the collectors or base bus traces??

Heck Ya!!. Thought you would like that.

I did run the straight edge a couple times and it checked out fine. I will have to check the continuity between ground and collector/base. the reason I am concerned is because I checked the continuity between the screw holding the thermal device in the middle and some of the jumpers across the right backboard

 

[laatsch55]

Would you take a pic of the top of the left backplane.?

 

[mjstriker]

Would you take a pic of the top of the left backplane.?

Can't take a pic cause I am working the night shift tonight. But I can describe. The red wire goes from the unfused B+ to positive on top power cap. Just looks a little funny cause the wire is long and loops

 

[mjstriker]

Justrealized pics I uploaded are small. Trying to figureout how to upload higher resolution

 

[laatsch55]

The loop is what got me Mike, thanks...

 

[mjstriker]

Can't seem to figure out how to upload higher resolution pics. When I upload from the computer to the website it always decreased size to just a few kb.

 

[laatsch55]

Go to your user control panel under general options and turn enhanced uploading OFF.

 

[mjstriker]

Here are the pics. Zipping them allowed me to do full size.

 

[NavLinear]

Looks like you'll need to pull the Zoebel network off the DC protect board. That's incorporated on the WO backplane boards. I don't have a schematic at my disposal but it's the big ass resistors (looks like one of them is R1) and one of the smaller blue caps for each output that need to be removed.

 

[NavLinear]

Here are the pics. Zipping them allowed me to do full size.

Ya know - you made me unzip. Got the full size tho...

 

[laatsch55]

Good catch, sure as shit.....remove R10, R11, C4, C5...

 

[mjstriker]

Good catch, sure as shit.....remove R10, R11, C4, C5...

So I remove the two big resistors along with the ones above? Looks like C4 and C5 and different resistor types and I do not see a R11

 

[mjstriker]

Also no continuity between ground points and Base/Emitter traces

 

[mjstriker]

I think I figured it out. Looks like R1, R2, C8 and C9 need to go

 

[mjstriker]

I removed the above resistors/caps and the unit passed the dimbulb test!!!

Reading through the assembly notes for the backplane it discusses only installing Q11 and Q12 to check the basic offset and bias functions. I did this and my bias is around 45mV in each channel but I can't adjust it much. Is this to be expected as I don't have all the drivers installed yet?

Thanks

 

[laatsch55]

Correct . Bias will come up but not that much. The resistors and caps need to come off the DC protect board. Those part numbers I quoted were for the dc board .

 

[laatsch55]

C's are caps.

 

[Gepetto]

I removed the above resistors/caps and the unit passed the dimbulb test!!!

Reading through the assembly notes for the backplane it discusses only installing Q11 and Q12 to check the basic offset and bias functions. I did this and my bias is around 45mV in each channel but I can't adjust it much. Is this to be expected as I don't have all the drivers installed yet?

Thanks

I would check further... The amp is functional with just the predrivers. Just will not support much of an output load.