2 PT-2 power transformers on 1 chassis--SR45 amp

[2wo]

Next would be to get the C4S for the driver working. The SS is set for 4.3ma, which is probably OK for now. Refer to the SR-45 schematic you can connect a 160k from bD to ground and remove the 300k RLd.

Now, from previous testing it look like the C4S was passing all the B+. This does not bode well for the active components. you can test the LEDs with your meter or a battery, if they light they're OK.

You can test the C4S. leave the 47K in series, Connected from pin 6 to OB and restore the B+ to IB.
If the C4S is working the voltage ACROSS the 47k will only be be a couple of volts. if not replace the transistors and LEDs and try again...John   
 
edit, check the voltage across the 47K before you make changes, so you know were you start

 

[Paul Birkeland]

If the C4S is working the voltage ACROSS the 47k will only be be a couple of volts. if not replace the transistors and LEDs and try again...John   
 

A working CCS feeing 3-4mA of current across a 47K resistor will make more than a few volts.

 

[howardnair]

john and paul--i will implement the changes and ck the voltages maybe tonite-monday evening i was force fed some nice bourbon from the local distillery--there was some fallout from this-ie; late evening, inebriation-the next day--howie

 

[Grainger49]

Oooooo... I need to be force fed some Bourbon. 

I had one last drink from my Woodford Reserve before working on the Crack I am trying to get well this evening.

 

[2wo]

Have fun, Paul is right about the voltage across that 47k. As usual I got the decimal wrong...John

 

[howardnair]

john ----i had to replace 1 led--prior to removing the softstarts and with b+ hooked -OB to 6 and the 47k in circuit also-i get 200v at pin 6--i then removed the bds replaced the one led that did not light- same one both bds-pulled the 2907's and cked them -they are fine so it seems are the 5371 transistors-using a fluke 115-i would replace  them just to be sure  but have been let down by the mail-you asked to me  remove the 300k Rld and install a 160k to ground at bD-i have no bD-i have bB-i have a Rdb which was the 33k across the 10,000uf cap-could you clarify this plz-
Grainger-the bourbon that was forced on me is from a local distillery called Triple 8
the bourbon goes by the name of Nor'Easter--it is a little too easy to drink-I suffer badly when i drink to much
thanks howie

 

[2wo]

Sorry I meant bB, the lower end of the 149K R2(b). Looking to break the connection to Kreg.

Adding the 160k from there to ground gives you ~309K, look at the SR Schematic  .

Once you think it is working you can replace the 47K with a 1K. If the C4S is working you should see something like 3-5 volts across it and about 200V at pin 6...John 

 

[howardnair]

john - I know this might be a stupid question-do i want to go to ground  or -reg on the board

 

[howardnair]

OK-i took the 160k to ground actually 150k for the moment--with 6.9v at pin 3 --i get 202v at pin6
no led's light up-the music plays-rt now it is just a ipod and some crappy speakers---just so we are on same page-the 47k is still installed-the 10000uf is not reinstalled and neither is the 33k -b+{IA]  is not connected nor is zener string

 

[2wo]

150k may not be enough, I have not calculated the diode current. Add 15-20k

Then measure the voltage across each led, be careful. Looking for 1-2v. Specify  1.5-1.7v...John

 

[howardnair]

upped to 168k -pin 3 6.9v and pin 6 204v----0v across the led's--cked them again with battery- still good--

 

[2wo]

If you have B+ at LED 1, then something is not connected right. Its only 2 LEDs and 2 resistors. You should be able to figure it out...John 

 

[howardnair]

where did i go?--i didn't --the slowstart bds did go--they do not like to be fooled with -i bought a ccs from k&k audio hooked it to the plate of v1 of the 6cm7 put a 2.k cathode resistor and 33uf cathode bypass cap in and i am using the  amp without the second half of the  6cm7 tube -it sounds very good and the voltages are in line-i am considering using a 76 tube -the modifications would be simple- except for  my wood top plate even though easily drilled would have to be completely refinished--i know the 76 has been used with a 2A3 but has it been done with a 45-any comments would be appreciated

i would like to thank john and paul for their help even tho it was to no avail--howie

 

[Paul Birkeland]

Yeah, essentially, you're rolling the amp back to being a Paramour-II, which is a good choice.

The 37/76 are nice old driver tubes, nothing wrong there!

 

[2wo]

OK, glad you got it going. Just check that you are not running the 45 too hard. we need the value of the cathode resistor, the voltage across it and the the voltage from the plate to ground...John