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Dynakit ST70 - Unopened and Untouched?

Was hoping it was a part number I could find a spec sheet for to take the guesswork out of this.

anyway, still looks like 6 and 9 are being used as output, so we need to know the AC voltage across those points to see if the stock bias system makes any sense. There are ways to work around it if the voltage is too low, but no point in getting ahead of ourselves here.

thats the annoying thing about undocumented modifications, it takes a bunch of poking around to work out what was done and what we have to work with. At this point we really don't know if it ever worked in it's current form.
 
trainbuftony said:
Blueglow has a great video on deciphering unknown transformers. I suggest watching it, because 90% of what I'm about to want to share with you, he already describes better than I can.
Basically you need to figure out which terminals are connected with coils of wire and see what voltage is present on them to see if you can get sufficient voltage to build a bias supply. Anything from about 25 to 100v will work.
If it's only giving you 5 or 8 volts, it may be prudent to bite the bullet and buy a (<$20) bias transformer which gives voltage that's more useful.
(Think 120v to 50v)
Be thankful you don't need any real current because that would definitely drive up the price.
(A quick Google search verified that $12 will get you a suitable transformer, $20 and it's at your door.)
Click to expand...
That is fantastic, thank you very much for your continued help Tony! I have watched some of his videos in the past for entertainment, I will watch the suggested video with a pen and paper/ ST-70 and figure it out!

I am also going to compile a list of parts to order, I figure I may as well order all of the required parts for the eventual dual-rectifier upgrade. I am open to any suggestions on what parts to order as well.
 
gadget73 said:
Was hoping it was a part number I could find a spec sheet for to take the guesswork out of this.

anyway, still looks like 6 and 9 are being used as output, so we need to know the AC voltage across those points to see if the stock bias system makes any sense. There are ways to work around it if the voltage is too low, but no point in getting ahead of ourselves here.

thats the annoying thing about undocumented modifications, it takes a bunch of poking around to work out what was done and what we have to work with. At this point we really don't know if it ever worked in it's current form.
Click to expand...
I am getting a reading of 17.5V between tap 6 and 9, looks like I will be ordering some new parts today! I am going to watch the video and hopefully figure out what that transformer is doing!
 
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ok, so thats not near enough to make the stock setup work. That would give around 25 volts DC which jives with what you were measuring.
 
won't help enough I don't expect, 17.5vac has a peak of 24.5 volts, factor in forward drop in the rectifier and it will be less than that. If there was any kind of load on it you'd get considerably less. Basically you need either a lot more AC volts into the rectifier, or a voltage doubler to try and make enough DC volts to get the job done.
 
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