Glen's 700 series II build

grapplesaw said:
I am looking for the thread which I read with all the steps to bring this puppy to life, so if anyone can help me please to find it I would be thankful. Want to put some juice to it before putting in the power transistors
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The powerup procedure was on "nelsress begins his WOPL 400 project":

http://forums.phxaudiotape.com/showthread.php/5611-nelsress-begins-his-WOPL-400-project/page23

Go to post #125.

I remembered this specifically because I copied it into a MSWord docx- I'm surely gonna need it later.
 
Well after reading the link Mark posted earlier I set out to get this thing to launch.

The new B backplate boards are a lot easier as you will see in my next thread, the upside down unit.

This one is type A backplates so all the transistors have to be soldered. Joe had pointed out not to put on two much solder on the joints. So I put in the first bottom row and flipped it up so I could easily solder them . After that I fired it up and got wild voltage readings, oops to much solder and it flowed to the base and shorted on of the transistors. Having used the bim bulb and varic set up not damaged done. Re and re'ed the bottom row and all went well. Did each row and now done
set bias at .350 volts and for 17 mv across the output. And 132 volts across the two supply caps

top left is rail voltage
lower left two bias
lower right two output voltage

will run some load test tomorrow
 

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Your bias will change when you are straight through....it looks like you are running 66volts+/- dc on the rails when you should have right at 100.....when off the DBT.
 
laatsch55 said:
Your bias will change when you are straight through....it looks like you are running 66volts+/- dc on the rails when you should have right at 100.....when off the DBT.
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So the bulb is a bigg resistor and I forgot about it
thanks Lee
 
Yes and it does exactly what we hope it will do....absorb abnormal amounts of CURRENT!! A variac will limit VOLTAGE but not CURRENT...that's why we use both...
 
laatsch55 said:
Yes and it does exactly what we hope it will do....absorb abnormal amounts of CURRENT!! A variac will limit VOLTAGE but not CURRENT...that's why we use both...
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Ok I got caught with my pants down . So I went and reset it. Got 209 - 210 volts across the caps or 105 rail voltage. That should work. Nothing to out of spec. Reset see shot
 

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laatsch55 said:
Keithly??
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You got it. I wanted to get a 5 1/2 or 6 1/2 digit multimeter. I had been looking at a hp 34401 and 3489 on eBay for some time. The keithley are more used for militatary and lab use and not to well know. Fluke has bought them now but these are from the 90's I got two 5 1/2 units and liked them a lot. I was looking for a 4 1/2 digit for doing my cap conditioning and bid on two different ones on eBay. My luck I got both. One came with a spare unit which had a non working display. I repaired it with some isopropanol cleaning of the contacts on the display. So I guess I will have to put a couple on sale in the future.

by the way Lee did you get my check? I have not seen it clear yet.
 
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grapplesaw said:
You got it. I wanted to get a 5 1/2 or 6 1/2 digit multimeter. I had been looking at a hp 34401 and 3489 on eBay for some time. The keithley are more used for militatary and lab use and not to well know. Fluke has bought them now but these are from the 90's I got two 5 1/2 units and liked them a lot. I was looking foe a 4 1/2 digit for doing my cap conditioning and bid on two different ones on eBay. My luck I got both. One cam with a non working display which I repaired with some isopropanol cleaning of the contacts on the display. So I guess I will have to put a couple on sale in the future.

by the way Lee did you get my check? I have not seen it clear yet.
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Here is some info http://en.m.wikipedia.org/wiki/http://en.m.wikipedia.org/wiki/Keithley_Instruments
they are gone to the dogs today, merged and all rapped up with Tecktronics and Fluke - made in China today
 
Yes I did Glen, it's been riding around in my wallet till I get to the bank...that's some lovely test equipment Glen....love it...
 
it is alive


Thanks for getting that link correct

so after a little swap of one defective meter board the results are in

100 hz in at 1.6 volts in
57.5 volts out into 6.9 ohms ( if I am right) should give 479 watts one Chanel only driven
both have same spec.
 
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