phase linear 400

[gene french]

got the new to me 8 fin in today....
pretty rough....the meters had slid down out of the holders....inside has stuff growing in there....looks like gaulded aluminum specks ....
pulled all of the drivers and outputs....all of the outputs tested bad...but in a strange way....showed shorted b to e....and not any other way...
i just dont have enough experience to recognize any significance if there is any....
the two agx fuse caps were missing...thankfully mr. george put two in a care package he sent to me when i made a donation for a 14b board...
saved the day mr. george....
all of the driver transistors tested good...
bias transistors tested good...
did not go much farther....
big caps showed 7500 uf....
nothing puffy showing...
want to check the transformer and rectifier....but unsure how since the blown/missing fuses....dont want to do any more damage...
i believe that the fuses were bypassed....since it got both sides in the same way...just a guess...but, i am sure you all have figured that out...
i need to order the ps caps and led upgrade from mr. joe......but want to make sure the transformer is good .... will just probably get a snubber rectifier from mr. joe...they are cheap enough....
just to be sure...
i think i have enough 909s to repopulate...to see if it will run....
no other obvious burns/shorts/damage showing...
any advice how to proceed to check the transformer without burning up anything else...????
the meters are dixon....someone has been into them...mounting screws missing...the faceplate bent to touch the needle....
burn marks from the bulbs...but normal i would think...and loose bulbs broken bulbs inside the meters....
maybe a good cleaning/lube will help them along...
would appreciate any comments or advice....
thanks ....

 

[gene french]

it did happen...lol

 

[George S.]

Disconnect the B+ and B- wires from the caps (the insulated flexible wires that go from the rectifier to the caps, remember? B+ and B-).
Set your meter on DC volts. Negative meter lead to the copper bus bar. Positive lead to B+ flexible wire from rectifier. Should read around +80 VDC. This is the upper wire.
Now put the Positive lead on the other flexible wire from the rectifier, the B- wire. Meter should read around -80 VDC. This is the lower wire.
Don't forget the main fuse before you do this. Betcha the 120 VAC to 80 VDC B+ and B- tests good. Around 160 VDC potential out of that center tapped transformer so use good care and don't short it out.
Easy to test that section. Have fun! Break in that new Fluke!
Oh, and also test for that potential, negative on B-, positive on B+.

 

[gene french]

Disconnect the B+ and B- wires from the caps (the insulated flexible wires that go from the rectifier to the caps, remember? B+ and B-).
Set your meter on DC volts. Negative meter lead to the copper bus bar. Positive lead to B+ flexible wire from rectifier. Should read around +80 VDC. This is the upper wire.
Now put the Positive lead on the other flexible wire from the rectifier, the B- wire. Meter should read around -80 VDC. This is the lower wire.
Don't forget the main fuse before you do this. Betcha the 120 VAC to 80 VDC B+ and B- tests good. Around 160 VDC potential out of that center tapped transformer so use good care and don't short it out.
Easy to test that section. Have fun! Break in that new Fluke!
Oh, and also test for that potential, negative on B-, positive on B+.

i can do that...i was thinkin that leaving out 5 amp agx fuses and checking on the fuse holder using bus bar as common...might work too...since no fuses...no voltage any farther down....i did use the new fluke on the transistors!!!

 

[gene french]

thanks mr. george....
i will let you know what happens tomorrow...
good night all...

 

[MusicSteve]

thanks mr. george....
i will let you know what happens tomorrow...
good night all...

Gene
Good testing so far w the Fuses out, still have voltage going to the board.
just a quick look,
Definably would use a Light bulb limiter. w be nice to uses different light bulbs and bring it up slowly to reform the capacitors.
I would also look at the AC wires going to the Temp-sw they look burned ?
and check all the backplane 10ohm resistors and diode's they look burned also or just dirty.
good luck

 

[Gepetto]

Gene
Good testing so far w the Fuses out, still have voltage going to the board.
just a quick look,
Definably would use a Light bulb limiter.
I would also look at the AC wires going to the Temp-sw they look burned ?
and check all the backplane 10ohm resistors and diode's they look burned also or just dirty.
good luck

They are not burned Steve, those wires insulated by the fiberglass jacketing just have that mold growing on them that occurs on that stuff for some odd reason. I have a couple of hulks I acquired with similar growth on them.

 

[MusicSteve]

They are not burned Steve, those wires insulated by the fiberglass jacketing just have that mold growing on them that occurs on that stuff for some odd reason. I have a couple of hulks I acquired with similar growth on them.

LOL

 

[gene french]

whats the best way to clean that up??

 

[WOPL Sniffer]

They are not burned Steve, those wires insulated by the fiberglass jacketing just have that mold growing on them that occurs on that stuff for some odd reason. I have a couple of hulks I acquired with similar growth on them.

Cut them in half and count the growth rings, you can tell how old the amp is.

 

[e30m3mon]

whats the best way to clean that up??

I was thinking gasoline and a match!

but seriously, if you are going through the amp, why not start with using that outstanding teflon wire from Nav? You probably have a bunch already.

 

[gene french]

Cut them in half and count the growth rings, you can tell how old the amp is.

lolololol

 

[gene french]

I was thinking gasoline and a match!

but seriously, if you are going through the amp, why not start with using that outstanding teflon wire from Nav? You probably have a bunch already.

i got a selection of the wire i got from joe....when i order i get some...yes ... gonna go through it ... to ser if i can....i think i can do this...

 

[gene french]

They are not burned Steve, those wires insulated by the fiberglass jacketing just have that mold growing on them that occurs on that stuff for some odd reason. I have a couple of hulks I acquired with similar growth on them.

Gene
Good testing so far w the Fuses out, still have voltage going to the board.
just a quick look,
Definably would use a Light bulb limiter. w be nice to uses different light bulbs and bring it up slowly to reform the capacitors.
I would also look at the AC wires going to the Temp-sw they look burned ?
and check all the backplane 10ohm resistors and diode's they look burned also or just dirty.
good luck

yes, i saw that....quickly abandoned my idea....mr. george as usual knows best...
when i tested using the method george suggested...
from the rectifier disconnected from the caps...
i got plus and minus 57 volts...with or without dim bulb tester....
as previously in this thread....joe confirmed that was the right reading out of circuit....
seems the rectifier is rectifying and the transformer is transforming...
been cleaning a bit...alcohol and a toothbrush is working nicely....
now i am confident enough to order new caps and led board from joe...
already got a dcp board on the way....
this one is in rough shape...rode hard and put up wet...
i shall see where this path takes me...
thanks steve george and mr. joe...

 

[George S.]

Maybe my wall voltage is different. Usually runs around 118 VAC.

 

[George S.]

Right around + and - 100 VDC on a 700. Get same voltages regardless if caps are connected or not.

 

[gene french]

Right around + and - 100 VDC on a 700. Get same voltages regardless if caps are connected or not.

mr. george...the latest 400 has a 14b driver board...both 1304s and 1305s are corroded and legs missing...pots are very rusty...rest is not so bad...i have your 14b board and 2 14a boards that i have collected ...would it be better to do a board swap or repair the board as i go??...should have parts...either was...1 14a board is burnt with melted traces...are the 14a pots and 14b pots the same??
tell me please what you would do...music man???
your 2 cents worth...anyone ???

 

[Gepetto]

if it is an 8 finner, replace everything with new. 8 fin units are keepers.

 

[gene french]

if it is an 8 finner, replace everything with new. 8 fin units are keepers.

thank you mr. joe...it is an 8 finner...

 

[George S.]

Listen to Joe. He has this all figured out.