Mutron transformer?

[BillyJ]

Ugh I bought a broken mutronIII thiking I could whip it into shape as I dd before with a friends (Thanks to help from here).
No such luck though as this particualr unit doesn't use batteries at all but rather has an internal transformer.
Well it looks like it has been messed with inside....
The transformer is held together with electrical tape......LOL!
Anyway it looks like perhaps someone tried to replace the transformer and who knows what they put in there....
In any event I would like to replace the transformer witha proper replacement but I have no clue what one would be.
I looked at all the mutronIII schematics but they all seem to want to use an external transformer....  :cry:
If anyone can help me out in finding the right one that would be great!!
Thanks a million!

[toneman]

just find out the pwr(voltage) requirements, then,
build a  1 ic regulator, using a xfmr that
will B sufficient 2 make the reg work.
Usually, regs require 3VDC above the regulated V.
Looking @ a schemo("orig") i C 6 opamps pwred by
9VDC.  Use LM317 adjustable reg.
U can experiment with resistors 2 get 9V, OR
visit GEOFX 4 an article on selecting Rs 4 the LM317.
stayfuzzed, err enveloped
tone

[Peter Snowberg]

The transformer is held together with electrical tape......LOL!

That can't bee too good of a sign.

Since that unit wants a dual supply, there are several ways you could go depending on the parts you can find sitting around.

The first way would be to use a transformer that puts out roughly 24 volts, run that into a bridge rectifier, add some good sized filter caps (as big as you want), use an LM317 to regulate that down to a clean 18 Volts, add a couple small caps to stablize the regulator, and then rig up an "artificial ground" using an 18V version of the LM386 or almost any opamp. That will effectively give you a bipolar 9 Volt supply.

Another way would be to build a regular 9 Volt supply and use a MAX1044 to generate a -9 supply from the +9. This may be simpler, but you can run into problems with noise from the MAX1044. See R.G.'s Neutron schematic at GEO for a picture of this method.

Depending on the transformer you find, you have a few more options. If the transformer has two isolated 12V secondaries, tie them together to make a single 12-0-12 secondary. Otherwise, just follow this schematic:

 

Take care,
-Peter