.
Sir Chad . . . . . .
I'm tuning in late on a quite progressed thread . . .BUT . . . .
By using creative thinking to "get your money for nothing and your chicks for free", you could save yourself some of your
"hard earned munneys" and use your already " paid for" . . . . . .and quite heavily, I might say. . . . .Power Transformer,
with but a slight modification to it
I am no stranger to changing transformers to my needs or even winding them myself from scratch.
Now, that extends back to the "olde tymes" when they were almost exclusively constructed as shown below:
In that manner of construction the primary winding was the very bottom winding and then there was an insulative barrier and the secondary winding was wound above, and on top of the primary winding.
That transformer secondary is our point of interest.
If I needed less voltage on a secondary winding, all that I needed to do was carefully remove the protective fish-paper outer insulation over-wrap and then a bit of waxed paper wrapping and I would then see the exposed enameled wire of the secondary winding.
Now, on YOURS, its using split bobbins and upon that secondary windings exposure, it should looka- like-a- 'dis.
The working room and access on this type of transformer construction below, is a dream.
So with a methodical procedure of progressively taking off turns will let you get ANY lowered voltage that you want.
Be it that mentioned 10 VAC or the lowest mentioned 8 VAC.
Now . . . HERE . . is where I need my assumption, being confirmed by you, that the transformers center tap wire is sitting there taped up and unused / unconnected.
Since I am seeing a Full Wave Bridge rectification manner, being utilized.
If you have not progressed too far, would you want me to fill you in on that simple transformer procedure . . . .if so, let me know.
Reading about your " resistor located and connected to the '350's".
It looks to be one of the two voltage divider resistors that you are needing if wanting to make a LM350 output adjustable, it, along with the companion frontal adjustable pot that you are presently using.
For your " touchy" adjustment of that pot, look into finding a surplus one of these, of that pots value, and use it . . . . .it takes TEN turns, count em', TEN !, to go thru its complete ohmmic adjustment range . . .
now . . . . . talking about VERNIER adjustment !
http://www.mouser.co.uk/ProductDetail/Bourns/3590S-1-502L/?qs=ka0oSW1bB1L/KiVO5%2b8CPQ==&gclid=CObE0qe6vsoCFQ8taQod8DQCFA
(Since your "Earth" location is quite broad geographically, look it up again on the proper site and note that this is data on a a 5k but 1 k's are also available.)
73's de Edd
.
