700 B WOPL New build Question

[mattoe]

Yes,

No problems until the driver board install.... First row of T03's, then checks for ground and voltage at the test points.... Repeat for each row.... Used the DBT and my Variac.... So close yet so far .......

Mattoe

 

[Northwinds]

Sounds like something is wrong with the populated driver board, anything in backwards, forgotten or out of place?

 

[Gepetto]

Yes,

No problems until the driver board install.... First row of T03's, then checks for ground and voltage at the test points.... Repeat for each row.... Used the DBT and my Variac.... So close yet so far .......

Mattoe

Can you provide a picture of the control board assembly?

Make sure that you have ~-100V on pad 3L of the control board. Make sure you have the 22.1 ohm resistor in location R39L on the control board and that it measures 22 ohms. Make sure you have a 1 ohm resistor in location R36L of the control board and it measures ~1 ohm.

And of course check your B- fuse on the left hand side.

 

[mattoe]

Thanks Gepetto !

Yes... -103v on pad 3L
Yes... 22.1 ohm in R39L and measured @ 22.0 ohm
Yes... 1.0 ohm in R36L and measured @ 1.0 ohm

Picture attached !

 

[Gepetto]

Thanks Gepetto !

Yes... -103v on pad 3L
Yes... 22.1 ohm in R39L and measured @ 22.0 ohm
Yes... 1.0 ohm in R36L and measured @ 1.0 ohm

Picture attached ! View attachment 27247

Are all the pins in U1L properly in the socket? Sometimes they fold under instead of going in the socket ferrules.

Do you have +15V on pin 7 of the OPA134 and -15V on pin 4? If you have +100V on the output then you should be seeing ~-14V at pin 6 of the OPA134. And about -13V on the emitter of Q1L.

 

[laatsch55]

And a diode in backwards maybe...

 

[Gepetto]

And a diode in backwards maybe...

They look to be installed correctly Lee...

 

[laatsch55]

Hookay.....

 

[Gepetto]

Insure the heatsinks on Q6 and Q9 are not twisted and touching any traces. I always push these heatsinks as far to the top of the board as possible while the securing screws are loose and then tighten the screws. That ensures the maximum clearance to any adjacent traces.

 

[mattoe]

Ok , Back with some numbers...

The pins on both OPA's are properly indexed... looks good...


OPA voltage checks: Pin 7 -1.16v left -0.35v right
Pin 4 -15.4v left -15.4v right
Pin 6 -0.32v left +15v right

Q1L emitter -0.6 v ???

I checked the heatsinks for Q6 & Q9... all good... close tho' eh ?

Diodes are all in correctly..... and test ok....

Thanks... I'm buried with this.....

Mattoe

 

[jbeckva]

Ok , Back with some numbers...

The pins on both OPA's are properly indexed... looks good...


OPA voltage checks: Pin 7 -1.16v left -0.35v right
Pin 4 -15.4v left -15.4v right
Pin 6 -0.32v left +15v right

Q1L emitter -0.6 v ???

I checked the heatsinks for Q6 & Q9... all good... close tho' eh ?

Diodes are all in correctly..... and test ok....

Thanks... I'm buried with this.....

Mattoe

Pin 7 doesn't make sense.. it should be +15 both left and right, and since the right channel is "ok" ??

Just making sure... if you look at the chip with the notch to the left, it goes left to right on the bottom pins 1 through 4, then right to left up top pins 5 through 8 (counterclockwise from the bottom-left / pin 1). Something like this..

8-7-6-5 (top pins)
>OPA-|
1-2-3-4 (bottom pins)

Now just assuming you may have pins 6 and 7 reversed in your measurements, that in itself would indicate you're not getting your +15 on the left channel (pins 7 L/R, 15 volts on the right which is "ok" versus -.32 on the left). R41L would be suspect - with power off, it should be 10 ohms. If it is 10 ohms and you basically see 15 volts on one side, and -.3 on the other, that means the entire 15 volts is being dropped, which would be a huge issue current wise (something would be a-smokin... ).

(orr.. if you happen to not have R41L installed... yahaa... )

 

[mattoe]

I posted that quickly and then went back to the bench... Thinking to myself..... Self, I said ..... This doesn't make sense.... So I got the pin configuration correct now.... arg...
and we have more sensible numbers to work with ....

pin 7 left -.3v right +15.06v
pin 4 left -15.6v right -15.6v
pin 6 left -1.1v right -0.355v

Brain fart.......

 

[jbeckva]

R41L is missing..

 

[mattoe]

Gentlemen .... It is with much sadness I admit to my grievous error...... But on a better note.... Its alive ! ......

"DUMB DUMB" award to Mattoe for NOT installing R41L.....


I will post back in a couple of days once I get it finished and set up to torturing my V5 Paradigm studio 100's


I'm going to down a beer or 2 and maybe just watch tv for a bit .... arg....


Mattoe.....

 

[laatsch55]

Not as bad as not installing a diode, or installing one backwards....

 

[laatsch55]

R41L is missing..

Good sleuthing Jer!!

 

[orange]

Not as bad as not installing a diode, or installing one backwards....

Can't reverse the polarity or combine the streams...

 

[jbeckva]

Gentlemen .... It is with much sadness I admit to my grievous error...... But on a better note.... Its alive ! ......

"DUMB DUMB" award to Mattoe for NOT installing R41L.....


I will post back in a couple of days once I get it finished and set up to torturing my V5 Paradigm studio 100's


I'm going to down a beer or 2 and maybe just watch tv for a bit .... arg....


Mattoe.....

No sweat man... all's well when ya first hear that puppy sing after a good fight to get it there!

 

[mattoe]

3300 Preamp ?

Does anybody want to part with a 3300 preamp ?

Mattoe

 

[Gepetto]

Does anybody want to part with a 3300 preamp ?

Mattoe

Matt
A much better choice is the RL11