phase linear 400

MusicSteve said:
Gene
Did you check the four .5amp fuses that go the the control board yet?
Click to expand...
i checked all fuses....the four on the backplanes and the three in the main amp chassis....one 5amp agx fuse was bad...but, you could not tell it...
i always check with a meter...just to be safe...but the filament was still in place...the fuse looked good...but, i have seen that before also...
i have now repopulated three rows of outputs one row at a time and no more dc on the left output channel...had a hard time accomplishing this trouble shootiing... as when i tightened the outputs....the dbt would burn bright and not dim...evidently something was touching somewhere when i tightened the bolts...once when i installed the second row...it again failed...being totally lost....i just gutted everything...which gave me a chance to check the back of the bias transistors as i installed them from the top....cleaned and recleaned the backs...checked for long wires....or anything else that was not pleasing to the eye...just to be safe......i used a old 4 fin for the base unit for the wopl build....and the old 4 fin heat sinks did not exactly match the holes in the chassis that i got from joe (as i had posted earlier) and ...to leave no stone unturned i rereamed all of the leg holes for the outputs...on bit size bigger...and deburred with a countersink ...i even used new sil pads even though i could see nothing wrong with the old ones...that seemed to work and i let it cook for a bit...the dcp board is now engaging, all voltages look good...i will recheck the bias when the new replacements get here...
 
well, well....
got the other two switches installed without incident...was very careful with the solder....lol
i read in this thread about using double shielded mike cable for low voltage cables....
i got some belden cable and nice looking gold plated rca males...
got all new cables made up...and installed....
looks nice....
joe has sent the replacement left channel outputs....he promised he would not get them confused with the right channel....
whew....i am so lucky to have joe looking after my interests!!!!
will be back in business in the near future....
no problem as i have 3 others as spares....
lol
i do love doing this...
 
Gene,
I always remove the heat sinks and take a flat file to the transistor seating surfaces. If it is flat, the file just glides on the dark anodizing. If there is a high spot from a defect or a dent where some goofball dropped something onto the soft aluminum surface; it shows up. Then I chamfer each hole that a Sil-Pad would be touching, and never re-use a Sil-Pad, they are not very expensive.
I have had several heat sinks with high spots that were likely burn-through pits and craters, these would likely have pushed through a Sil-Pad. I resisted Sil-Pads for a long time because I was a Mica and Grease man. Eventually, Joe convinced me about the time-saving qualities of the Sil-Pads, but nothing will push through a sheet of mica.
And, I torque each screw to 7 inch-pounds with a calibrated torque screwdriver. I have not since had any problems with my flattened, chamfered heat sinks and Sil-Pad interfaces.
 
I do the same with a strip of fine wet and dry sand paper under my finger tip. High spots show right up and bare aluminum gets cut down flat quickly. It's actually easy to over do it and remove that good insulating anodizing.
The one thing I learned to not do is try to machine a chamfer. Even a tapered reamer leaves a ridge that needs sandpapered off.
 
George S. said:
The one thing I learned to not do is try to machine a chamfer. Even a tapered reamer leaves a ridge that needs sandpapered off.
Click to expand...
You have to do it by hand and roll it around just a little bit. I get a single clean chip with my Cleveland 100 degree countersink bit mounted in a hand chuck.
 
mlucitt said:
Gene,
I always remove the heat sinks and take a flat file to the transistor seating surfaces. If it is flat, the file just glides on the dark anodizing. If there is a high spot from a defect or a dent where some goofball dropped something onto the soft aluminum surface; it shows up. Then I chamfer each hole that a Sil-Pad would be touching, and never re-use a Sil-Pad, they are not very expensive.
I have had several heat sinks with high spots that were likely burn-through pits and craters, these would likely have pushed through a Sil-Pad. I resisted Sil-Pads for a long time because I was a Mica and Grease man. Eventually, Joe convinced me about the time-saving qualities of the Sil-Pads, but nothing will push through a sheet of mica.
And, I torque each screw to 7 inch-pounds with a calibrated torque screwdriver. I have not since had any problems with my flattened, chamfered heat sinks and Sil-Pad interfaces.
Click to expand...
i am sure that was part of the problem...in joes docs he warned about dull punches used by phase linear...i did not reuse the sil pads when the problem reassembly started...i have a calibrated wrist...i set it to snug...not tight ...not loose...i have a bit more 1/16 " of the legs pokin through the back planes...clearly sufficient contact...i dont think anything else was wrong....just three outputs bad...
i could see where the line of silder touched an output...
thanks!!!
 
mlucitt said:
You have to do it by hand and roll it around just a little bit. I get a single clean chip with my Cleveland 100 degree countersink bit mounted in a hand chuck.
Click to expand...
i did not put countersink/champher bit in a drill...only by hand...dont take much..
tried to disturb as little anodizing as possible...
this troubleshooting gave me a chance to address things that did not occur to me the first time...i felt much better after disassembly inspection champhering and reassembly...
 
Gene, if your going to pull the bell to install a foot, you may as well upgrade your bolts to use the step washers. Also consider Phoenix Contacts on the backplanes. A strip of fine grit wet/dry under you fingertip with proof your heatsinks easily and quickly. Have fun!
 
George S. said:
Gene, if your going to pull the bell to install a foot, you may as well upgrade your bolts to use the step washers. Also consider Phoenix Contacts on the backplanes. A strip of fine grit wet/dry under you fingertip with proof your heatsinks easily and quickly. Have fun!
Click to expand...
you really dont realize how much i enjoy this!!!
thanks for the tips!!!
 
monday is mothers day in costa rica...
2 of marias boys are here....to celebrate with her....
the oldest abidan....has taken her for a day of treats....
they will eat lunch at rio perdio and visit the spa...take in a few sights together...abi will make this day all about her!!!
that is so nice to see....i love this for her...she is on cloud 9....lol
zach could not go...as he is working today...he works on line....
they are good kids....and she is a great mother....
a little on the tough side...but, that is a good thing...
she does what she has to do...i like that...definitely not people to run from problems....instead they roll up their sleeves....lol
a friend of zachs came over 2 nights ago for a little guitar jam...all sitting around the sala enjoying...a few neighbors came over when they saw the late night lights on....lol....sometimes we play music very loud....lol...
they were both quite good....actually better than i expected!!!
last night maria and abidan did some exhibition dance moves in the living room...that was so heartwarming....
they too were both quite good....actually better together than i expected!!!!
a nice time enjoyed by all....even jerry was tapping his toes...
take care guys...enjoy the weekend!!!!
 
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