My First Phase Linear Restore- New Guy to the Forum

[laatsch55]

I don't know either....

 

[Gepetto]

So looking over my work I have now realized that I made a mistake when replacing C2 and C9 (rated at 22uf 10V) and substituted 2.2uf 35V in its place. Don't know if that could be causing the loud hum (which appears to be 60 Hz) but it obviously needs to be corrected. Was using a bad pdf of the service manual and was able to get my hands on a better resolution one and realized there was not dot between the 2's. Waiting for the parts to show up as the leads on the old parts are too short now to put back in

Hopefully this rectifies the situation and I can move forward cleaning this unit up. Still waiting to get some quality time with the 400 now seeing as I have pretty much all the parts and just need some time to start the tear down.

Hi Mike
Those are truly 22uF in the schematic and it will not make a difference in your hum problem unless you are experiencing it in your turntable. Those are the MM phono amps.

Are C40 and 41 good? Do you have a connection between DC ground on the board and the chassis?

 

[mjstriker]

So I ended up not having a good ground connection between the board and the chasis. I had installed the center screw holding the board and not the two outside ones when I was testing the unit. Didn't realize at the time they were the actual grounding screws. Now it runs great. Next step is to clean up all the rca jacks and front pots then install the new replacement op amp with the brown dog adapter.

Thanks again for helping me narrow down the issue and learn a few things especially the basic stuff.

 

[Gepetto]

So I ended up not having a good ground connection between the board and the chasis. I had installed the center screw holding the board and not the two outside ones when I was testing the unit. Didn't realize at the time they were the actual grounding screws. Now it runs great. Next step is to clean up all the rca jacks and front pots then install the new replacement op amp with the brown dog adapter.

Thanks again for helping me narrow down the issue and learn a few things especially the basic stuff.

No Problem. Hum problems are most often ground related problems.

 

[mjstriker]

Still working slow and steady on the phase linear 400. Was browsing the threads and found some information on latch up tendency and placing diodes across C6 to help fix this. I think I have a handle on why the diodes would be beneficial but I was unclear on if it is something that should be installed automatically or only if I have issues. Also wasn't sure which diode would be appropriate to install

Thanks

 

[laatsch55]

By all means install them onany board that doesn't have them...1N4148's back to back, opposite polarity, twist the ends together and solder on the backside accross C6's leads. If you make C6 a 470uf/25 volt AUDIO GRADE cap it really helps the low end freq response....a Nichicon "Muse" or Elna Silmic II is great in the position..

 

[laatsch55]

Love the pic of the old cornbinder scout!

 

[mjstriker]

Love the pic of the old cornbinder scout!

The old scout is pretty awesome. It's my Dad's from when he was in his 20's. Never actually saw the thing running and my Dad sold it about ten years ago to someone who wanted to fix it up. Found the guy a few years ago and it had just been sitting in his yard. He never got around to getting it running so we bought it back and rebuilt practically the whole thing. Now it runs great as his in-town driver.

Barely goes 55 MPH but that thing will go up any hill you throw at it!!

 

[laatsch55]

That's what remember about em. An old friend in high school had one, took us to many a fishin hole ....

 

[Gepetto]

Still working slow and steady on the phase linear 400. Was browsing the threads and found some information on latch up tendency and placing diodes across C6 to help fix this. I think I have a handle on why the diodes would be beneficial but I was unclear on if it is something that should be installed automatically or only if I have issues. Also wasn't sure which diode would be appropriate to install

Thanks

Mike
I am pretty sure you are installing the WO board in your 400. Those diodes are standard part of that design and in the artwork.

 

[laatsch55]

OH SHIT.....I'll ask next time...

 

[mjstriker]

Wasn't sure if I saw them being installed on the back of the new WO boards in other threads. Thanks for the info.

 

[laatsch55]

No they aren't, no need to, already there..

 

[mjstriker]

So been a little sidetracked with work and haven't had too much time working on the PL 400 or PL 2000. Mostly just listening and enjoying when I can.

HAd a little time today so I broke down the PL 2000 to clean the jacks, switches and gunk all over the solder joints. Went well and everything seemed to go back together nicely. Unfortunately didn't play very nicely. I have lost the left channel during stereo. Service manual says either the IC is bad or the volume/power switch is bad. Since I replaced the IC with the upgrade with adapter I am left with the volume/power switch. Now I can get both channels to work fine in mono without issue it's just stereo.

What I am thinking is that I installed the volume/power switch incorrectly but I am not sure at this point. I was wondering if anyone knew a way of figuring this out or could take a picture of the back of there power/volume switch and maybe I could deduce the correct orientation. One thing I did try was take the rca plug and put it into the various outputs on the back but that didn't work

Thanks

 

[laatsch55]

You desoldered the swirch totally?

 

[wattsabundant]

I vote for the chip. Check for bent pins etc.

 

[mjstriker]

You desoldered the swirch totally?

Yes. Sounds like that wasn't such a good idea. The other switches had a lot of junk in them so I disassembled to give it a good clean.

The chip should be fine as it is brand new and the unit was working find after the install. Just started giving me trouble after I gave all the switches a good clean

 

[laatsch55]

I'll post a couple pics...

 

[laatsch55]

Here ya go..

 

[mjstriker]

Thanks for the pics. I should have clarified a bit more. I desoldered the pins from the board but not the wires. I then opened the switch to clean the guts inside. I am wondering if I put the insides back together wrong cause now I have no left channel except when I go mono. Haven't had a chance to open it back up but I am wondering if it only goes back together one way or I flipped something inside. All the other switches seem to be working fine.