phase linear 400

gene french

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guayabo de bagaces, guanacaste, costa rica....
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music...the healer of souls...
I cant speak for anyone here but myself but I would not have ever believed anyone would have ever mentioned the word "rainbows" in the same sentence with Perry. I don't think it was a jab but I thought it was funny. Looks like someone else did too so who knows. Joe may have been being crafty again.
glad to see you posting!!!
 

Sunnbobb

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I just finished reading War and Peace.. I mean this thread. What a great read and getting a feel for the Phx crew. I'm getting ready for WOPL #3, and having done 2 already, it was cool to read the thread. I sent my order into Joe, now time for some popcorn and Coffee. Gene, what's the best coffee you have found down there in CR?
 

Sunnbobb

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Hey guys, I have an interesting issue I have not been able to zero in on. Sometimes when I turn on the WO/WA 700 S2 (with WO led display), the right meter pegs and the bias on the right board registers zero. A good tap on the case causes it to drop to normal, and the bias returns. It then operates normally. I run the DBT and the variac and I have been stopping the variac at about 45V, which is when the LED meter comes on faintly and pegs. There doesn't seem to be any damage going on at this voltage, but I am hesitant to take it up to a higher voltage while pegged. After I tap the case, and the meter drops to zero, it can be run up to the full 117 V with no issues. I have probed, tapped and inspected as much as I can. After returning the meter to zero, Bias on both sides is typically .355, and there is no issue with the 15V test points. I'm just trying to figure out what to check in the circuit that could be the cause. Thanks for any ideas and or explanations of how to troubleshoot this.
 

George S.

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I'd first check for a short to ground, and I'd suspect it's at the silpads.
When the issue is active, unplug the amp, and disconnect the star ground from the chassis stud. If built properly, this is the only ground connection.
DMM set to diode mode, ground lead to chassis, start checking output transistor cases for continuity to ground.
They should be isolated from ground by the silpads, and it's very easy to over tighten and short a output.
That's what I'd check next if you haven't already done so.
Good luck, take your time and be careful not to make a error.
 

Gepetto

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I'd first check for a short to ground, and I'd suspect it's at the silpads.
When the issue is active, unplug the amp, and disconnect the star ground from the chassis stud. If built properly, this is the only ground connection.
DMM set to diode mode, ground lead to chassis, start checking output transistor cases for continuity to ground.
They should be isolated from ground by the silpads, and it's very easy to over tighten and short a output.
That's what I'd check next if you haven't already done so.
Good luck, take your time and be careful not to make a error.
You would be blowing fuses if that was the case. Look for wire connections that look like they are made but are not really. Are the Phoenix connectors tightened (not over tightened) or just loose? Do you have a solder joint on the control board that looks like it is there but isn't?
 

Hexis22

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Dec 28, 2022
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Wisconsin
Hey guys, I have an interesting issue I have not been able to zero in on. Sometimes when I turn on the WO/WA 700 S2 (with WO led display), the right meter pegs and the bias on the right board registers zero. A good tap on the case causes it to drop to normal, and the bias returns. It then operates normally. I run the DBT and the variac and I have been stopping the variac at about 45V, which is when the LED meter comes on faintly and pegs. There doesn't seem to be any damage going on at this voltage, but I am hesitant to take it up to a higher voltage while pegged. After I tap the case, and the meter drops to zero, it can be run up to the full 117 V with no issues. I have probed, tapped and inspected as much as I can. After returning the meter to zero, Bias on both sides is typically .355, and there is no issue with the 15V test points. I'm just trying to figure out what to check in the circuit that could be the cause. Thanks for any ideas and or explanations of how to troubleshoot this.
Sounds like you have an intermittent connection in your bias circuit.

Detailed pictures would greatly help provide feedback.

Perform a thorough visual inspection of all bias circuit connections.
- Transistor to backplane PCB (are the leads touching the P-Clamp, leads properly soldered to pcb)
- Did you stress the bias transistor leads while tightening the p-clamp to the stud (p-clamp rotated while tightening)
- Connections at both ends of the bias leads between backplane and control PCB
- Phoenix connector screws tight and pins soldered properly to PCB
 

Sunnbobb

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Hexis, thanks, I found exactly what you suggested. An intermediate connect it was! I also added another tool to my bench, a chopstick! I tapped every component with the chopstick until i found the offending resistor (R39). The chopstick helped keep me from electrocuting myself while trouble shooting a live circuit. One leg was wiggling ever so slightly when i pushed on it with the stick. Thanks you guys for taking the time to read my tale of sorrow. This board is the best. I'm looking forward to turning the neighbors on to some Buck Tick - Kemonotachi no Yoro.
 
Last edited:

gene french

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guayabo de bagaces, guanacaste, costa rica....
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music...the healer of souls...
I just finished reading War and Peace.. I mean this thread. What a great read and getting a feel for the Phx crew. I'm getting ready for WOPL #3, and having done 2 already, it was cool to read the thread. I sent my order into Joe, now time for some popcorn and Coffee. Gene, what's the best coffee you have found down there in CR?
there are many great coffees here....number 3 in the world for coffee production...
here is my all time favorite...
a bit on the expensive side...but, i am worth it...
lol

1706481040028.png
 

gene french

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guayabo de bagaces, guanacaste, costa rica....
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music...the healer of souls...
been busy lately, not much time to spend on the forums...finally caught up today...
been rebuilding lawnmowers and picked up a few more cows...getting things setup for the dry season....wont see rain again until first week or two of may....
projects, projects...no matter where you sit...one can see something that needs fixing...
today i got back to christine...after smoking (literally) a few parts....i gave up on original restoration...
i want a third wopl anyway....
just ordered the stuff a few minutes ago...
will do a semi quasi restore...this is only my spare machine...
maybe down the road i can add the back planes....
i already have the bigger caps, rectifier, and led board upgrades...
these pl14 boards are the worst of the worst...the bottom of the barrell...i know some think they were junk to start with...and thats ok...
eventually i will upgrade the last three 400s to wopls too...as i have 2 wopls full complimentary and 4 stock 400s with upgraded caps and led boards....
including christine......
i still have one hafler p230 to recap and upgrade...giving me 4 of them ....
my system as it stands now...
a smsl dac...hafler tuner...hafler preamp...hafler eq on the voights...dayton dsp actively controlling the 4 ways...
with the inline volume control with remote....that was a cool addition...
a pair of monoblocked haflers are driving the woofers
i will put the other pair of haflers on the 10" midbase speakers when i finish recapping the last one...one is done and waiting patiently for me to catch up....
and 2 stock 400s on the 6" mids and tweeters...
a wopl 400 stand alone is driving the voigts...
it really does sound clean...

i will take a wopl to the bedroom system...to replace the stock 400 in there....

and that will give me a free wopl 400 and a free 400....
not decided yet how i will reorganize....
but, have time to decide....

hope you guys enjoyed your sunday!!!
 

Gepetto

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been busy lately, not much time to spend on the forums...finally caught up today...
been rebuilding lawnmowers and picked up a few more cows...getting things setup for the dry season....wont see rain again until first week or two of may....
projects, projects...no matter where you sit...one can see something that needs fixing...
today i got back to christine...after smoking (literally) a few parts....i gave up on original restoration...
i want a third wopl anyway....
just ordered the stuff a few minutes ago...
will do a semi quasi restore...this is only my spare machine...
maybe down the road i can add the back planes....
i already have the bigger caps, rectifier, and led board upgrades...
these pl14 boards are the worst of the worst...the bottom of the barrell...i know some think they were junk to start with...and thats ok...
eventually i will upgrade the last three 400s to wopls too...as i have 2 wopls full complimentary and 4 stock 400s with upgraded caps and led boards....
including christine......
i still have one hafler p230 to recap and upgrade...giving me 4 of them ....
my system as it stands now...
a smsl dac...hafler tuner...hafler preamp...hafler eq on the voights...dayton dsp actively controlling the 4 ways...
with the inline volume control with remote....that was a cool addition...
a pair of monoblocked haflers are driving the woofers
i will put the other pair of haflers on the 10" midbase speakers when i finish recapping the last one...one is done and waiting patiently for me to catch up....
and 2 stock 400s on the 6" mids and tweeters...
a wopl 400 stand alone is driving the voigts...
it really does sound clean...

i will take a wopl to the bedroom system...to replace the stock 400 in there....

and that will give me a free wopl 400 and a free 400....
not decided yet how i will reorganize....
but, have time to decide....

hope you guys enjoyed your sunday!!!
Yeah it is championship Sunday here...
 

gene french

Veteran and General Yakker
Joined
Mar 6, 2022
Messages
5,316
Location
guayabo de bagaces, guanacaste, costa rica....
Tagline
music...the healer of souls...
last hafler recap/upgrade was uneventful....

got the 4 monoblocked hafflers in the system now...

2 p230s driving the woofers...
2 p230s driving the midbass...
one 400 stock driving the mids...
one 400 stock driving the tweeters...
all thru the dayton dsp...

one full wopl driving the voigts...thru the hafler eq...

gonna put the spare wopl in the bedroom....

and eventually wopl all of them....
awaiting parts from mr. joe...

rewarding experience....i appreciate all of the support/help to get this far....
bunch of nice guys here....
thanks
 
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