So, here I go. Phase Linear 400

62vauxhall said:
Sounds like the fruit of your karma tree hangs out of reach too.
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At least I know things are going to change. Not necessarily for the better but they are going to change ! Lol. I did find the leak in the pool today and got er patched up nice. Water going back in and tomorrow I will finish plumbing it up.
 
laatsch55 said:
Ok, here they are. Two things, when you get them you will see the P-strap will not contact the chassis when bolted so you will have to sand the bottom of the bracket to get the P-strap to contact the chassis. It has to contact the chassis in order to do it's bias thang as the chassis heats up. I am sending 2 extra P-Straps and 4 2N5088's. You will have to spread the P-Strap and punch out the old 2N3403, then clean out the old epoxy with a small file and the install the 2N5088, squeeze it together with a 4-40 screw and nut , then mix up some 5 min epoxy and put a dab inside the P-Strap opposite the lead side. The 2N5088 has a different pin out than the 2N3403 so download the data sheet. When you add wire to the leads to make it long enough top get to the back of the board, use #24 wire. use really small heat shrink or the bundle won't fit through the "tunnel" in the bracket. At the small end of the bracket, it is indented to accept a small cable tie. That will keep the strain off the leads, and prevent breakage....
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Finally back. As to the above. Cleaned with a small rattail file and used a bolt to pull P strap together. Transistor fits a bit loose. I can slide it out by hand with only a bit of resistance. Should the transistor fit snug, tight or a bit loose with the epoxy is OK ?
 
In order to keep from seeming absolutely useless I thought it over and removed just a hair of material from the P strap with jewelers file to make the transistor fit snug. Not tight and not loose.
 
Got em both in and they look real nice. Those strain relief parts are dandy. I see the old 2N3403 pinout is E C B
and the new 5088 pinout is E B C. Pulled the data sheet as you said . On my driver board they are marked at the solder points I am sure I solder by the board correct ? I know that is probably a dumb ass question however when it comes to swapping out transistors old for new I know next to nothing. Hitting a meeting from 8 till 9 EST so I will check in later. I will go no farther till you say so. They are mounted and ready to solder. Thanks.
 
VSAT88 said:
In order to keep from seeming absolutely useless I thought it over and removed just a hair of material from the P strap with jewelers file to make the transistor fit snug. Not tight and not loose.
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That's the ticket....
 
VSAT88 said:
Got em both in and they look real nice. Those strain relief parts are dandy. I see the old 2N3403 pinout is E C B
and the new 5088 pinout is E B C. Pulled the data sheet as you said . On my driver board they are marked at the solder points I am sure I solder by the board correct ? I know that is probably a dumb ass question however when it comes to swapping out transistors old for new I know next to nothing. Hitting a meeting from 8 till 9 EST so I will check in later. I will go no farther till you say so. They are mounted and ready to solder. Thanks.
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As long as you kept the colors the same for the Base, Emitter, & Collector----you're golden!!
 
VSAT88 said:
Got em both in and they look real nice. Those strain relief parts are dandy. I see the old 2N3403 pinout is E C B
and the new 5088 pinout is E B C. Pulled the data sheet as you said . On my driver board they are marked at the solder points I am sure I solder by the board correct ? I know that is probably a dumb ass question however when it comes to swapping out transistors old for new I know next to nothing. Hitting a meeting from 8 till 9 EST so I will check in later. I will go no farther till you say so. They are mounted and ready to solder. Thanks.
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You have good contact between the P-strap and the chassis??
 
laatsch55 said:
You have good contact between the P-strap and the chassis??
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Yes, the P-straps touch the metal on the chassis just fine. Should I use a bit of wakefield thermal compound behind them ? I did not see any compound when I removed the old ones. I used 24g wire as you said. From transistor to transistor the wire code/colors were kept the same. I used Orange for the Collector, Blue for the Base and White-Blue for the Emitter on both sides. I did not have Brown Black and Red in 24gwire.
 
VSAT88 said:
Yes, the P-straps touch the metal on the chassis just fine. Should I use a bit of wakefield thermal compound behind them ? I did not see any compound when I removed the old ones. I used 24g wire as you said. From transistor to transistor the wire code/colors were kept the same. I used Orange for the Collector, Blue for the Base and White-Blue for the Emitter on both sides. I did not have Brown Black and Red in 24gwire.
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Na, dry is fine. And as long as you know which is which, you are good to go...
 
Fire that puppy up, hook up the VOM and eyeball the bias as you bring it up on the blown channel...you should have more range on the bias adjustment with the 5088 in there...
 
laatsch55 said:
Fire that puppy up, hook up the VOM and eyeball the bias as you bring it up on the blown channel...you should have more range on the bias adjustment with the 5088 in there...
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So, just to make sure I understand. On the veriac On the DBT check Bias on both channels with both of my meters as I slowly turn it up ?
 
Correct on all....bias may run a little high with just the drivers in....
 
And as you see the driver board gain control, turn bias all the way down on both channels....
 
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