Cory's Phase Linear 2000 Ser II Restoration

[Gepetto]

I used the brown-dog adapter 060601 with OPA2134 chips to replace the original RC4136 .I matched pin 1 to the original it was the same as in the thread photos . It howls with the preamp off and amp on that's strange.
So I can go with a 5uf poly-pro film caps on the outputs (just checking)

Yes the 5uF polypropylene will be a big upgrade from the electrolytics.

 

[Gepetto]

The right channel went out and then hum ,thats when I turned off the pre and got the howl so I thought the two might be related . I'm going to test it with the original RC4136 and if all goes well I will try the brown dog again. I also clean the function switch again (may have caused the channel drop)

Does it howl with the Tone switch out and the Equalizer switch out? Try both positions to see if we can narrow this down.

 

[Gepetto]

The background hum I'm getting goes away when the unit is taped(cold solder joint?) .I did re-flow the solder joints on the pots and Jacks, I'll do the switches.
How come the brown-dog howls ? (sorry I couldn't resist) How come the brown dog upgrade IC's howl?

The OPA2134 has at least 8 times the gain bandwidth product of the original 4136 (8MHz vs 1 MHz for the 4136). I notice no local bypassing on the schematic for Z3 which is the one you replaced. It cannot hurt. The data sheet for the 2134 says this

Power supply pins shouldbe bypassed with 10nF ceramic capacitors or larger to​

minimize power supply noise.

 

[laatsch55]

" When the Brown Dog howls"
" Steer clear of the Jowls"
"And by-pass such"
"With Capacitance thus"
"That allows it to go away..."
Quietly......

 

[laatsch55]

Only 2 C & C's and a Fuzzy Baileys....

 

[Gepetto]

" When the Brown Dog howls"
" Steer clear of the Jowls"
"And by-pass such"
"With Capacitance thus"
"That allows it to go away..."
Quietly......

Nice Lee...musta been a good day

 

[laatsch55]

Horrible day, but a very good night!

 

[NavLinear]

" When the Brown Dog howls"
" Steer clear of the Jowls"
"And by-pass such"
"With Capacitance thus"
"That allows it to go away..."
Quietly......

Shit - kind of sounds like my limericks - maybe a little better than mine but not by much.

 

[NavLinear]

Only 2 C & C's and a Fuzzy Baileys....

A little heavy on the Crown I take it. Ya know - the Fuzzy Baileys is a chick drink.

 

[calman46]

Its a steady(Jack Daniels) howl , I'll try by-passing the power supply pins #7 & #11 on the adapter . Thanks

 

[Gepetto]

A little heavy on the Crown I take it. Ya know - the Fuzzy Baileys is a chick drink.

I have been partial to Hendricks dirty martini's lately, 2 olives. If you have not tried that Gin, it is great for martinis. I am pretty safe that is not a chick drink Dennis.

 

[Gepetto]

Its a steady(Jack Daniels) howl , I'll try by-passing the power supply pins #7 & #11 on the adapter . Thanks

I am pretty sure that the power and ground pins on the RC4136 were 4 and 11 from my recollection back to the early 80's when I first used that IC for motor control. I think bypassing from 7 to 11 may make is 'scream' instead of howl.

Does it howl if you use the 2nd set of outputs or are they OK?

 

[Gepetto]

Its a steady(Jack Daniels) howl , I'll try by-passing the power supply pins #7 & #11 on the adapter . Thanks

Do you have a PL power amp that is being fed by this preamp?

 

[calman46]

I have used it on a Luxman M4000 and now a Marantz 1060 (on the main in ,jumpers removed).both sets of inputs howl. I meant the pins 7,11 to ground sorry. I'm looking at the PL 2000II schematic and the + inputs go to ground pins 2,5,9,13. Pin 11 is B+ and 7 is B-. I'm not sure how to ground them now .

 

[Gepetto]

I have used it on a Luxman M4000 and now a Marantz 1060 (on the main in ,jumpers removed).both sets of inputs howl. I meant the pins 7,11 to ground sorry. I'm looking at the PL 2000II schematic and the + inputs go to ground pins 2,5,9,13. Pin 11 is B+ and 7 is B-. I'm not sure how to ground them now .

You are correct, 11 is V+ and 7 is V-

 

[NavLinear]

I have been partial to Hendricks dirty martini's lately, 2 olives. If you have not tried that Gin, it is great for martinis. I am pretty safe that is not a chick drink Dennis.

I haven't tried Hendricks but I'll have to give it a try sometime. Yeah Joe - I'd agree that this one's not a chick drink.

 

[Gepetto]

I haven't tried Hendricks but I'll have to give it a try sometime. Yeah Joe - I'd agree that this one's not a chick drink.

Straight up, shaken, not stirred Dennis

 

[calman46]

so I can just use any chassis ground near by ?

 

[Gepetto]

so I can just use any chassis ground near by ?

Not chassis ground, board ground

 

[NavLinear]

Not chassis ground, board ground

Looking at the board layout drawing and the accompanying schematic in the service manual there are two very convenient and co located components that are tied to board ground. R35 and R36 have one leg tied to ground and they are on either side of Z3 so this could be a very short jumper.