It seems to have a tda7377 chip amp and a fairly good looking toroidal transformer.
The transformer states 120vac input and 10.7VAC out at 4.05A AS WELL AS 12.6VAC at 1.2A.
I see two rectifiers and caps and cant follow the board traces to figure out how theyre used.

Any ideas or insight on how to get a project like this off the ground?
Not sure where to begin but am eager to re-solder some components.

Im guessing transformer has two non matching outputs; one for the amp side and then one for the computer and LCD circuit of this radio???

 

Good luck with reverse-engineering that device, the best thing is to ID as many semi devices and get some idea what is the function of the different stages.
This May help dividing the circuit up into various areas to investigate.
Starting with all the power supplies, for e.g.

 

Oh! Yes thats kinda where I Was going. I get ahead of myself.
The main question is how to utilize the transformer correctly.

I think I want to just make a standalone power supply.

Just the higher amp leg (10.7VAC/4.05A) would give me like 12v to power like a car stereo but what do i do with the other leg on the transformer? I have all the components... is getting a couple breadboard kits the way to go here?

I suppose I should power it up and measure the power I get from the rectifiers...?

 

You can see the VA size of the transformer by looking at the ratings of the secondary's.
Toroidal transformers are very easy to add or modify a secondary winding.

 

OK, the goal IS NOT to repair the radio, but to build something using some parts from the radio.
At least that is what I think the goal is.
Clarify what you want to make and suggestions will arrive.

 

Yes. Sorry.
I want to build the power supply out of the transformer, (with 2 outputs) the rectifiers and the capacitors.

Right now Im trying to figure out how to use those "circuit simulators" so I know what else Ill need to add after these three components & how to arrange them on a board I guess. Everyone elses "linear power supplies" have a bunch of other components after the rectifier and capacitor and thats where I lose track on this board and their diagrams.

Does this make sense? I fee like im still not thinking straight. pudding brains.

 

Generally that is all you need for a linear supply is bridge rectifier Unless secondary is centre tapped, then you just need two rectifiers, and suitable electrolytic capacitors.
This is where a linear supply beats a SMPS, in that it is rugged and simple.

 

What is after those components is usually the regulation section.

If you just use the transformer, rectifier and filter caps you end up with an un-regulated power supply, sometimes referred to as a "brute force" supply.

Brute force supplies have a use for motors and lighting and anything else that is a fixed load but little else.

In other words, they don't make a very good bench supply without the regulation.

 

What is your intended use for this power supply? What voltages and currents does it need to produce?

 

Brute force supplies have a use for motors and lighting and anything else that is a fixed load but little else.

In other words, they don't make a very good bench supply without the regulation.

? all the valve radios or audio amps I owned or built never used DC regulation.?

 

Search for the service manual, by make and model number.

 

You can have both. A repaired radio, and tapping from its supply circuitry, DC outputs to outside the cabinet for something else to work with specific tailoring or variable power circuitry. Start with response #11 above.

 

Ive tried to look this up a few times with no luck.
Its Boston Acoustics but the model of the unit itself I cant remember.
MD2201RA doesnt give me much from google.

Mand I gotta dust that thing. Its been on a bookshelf for months.

I couldnt "repair" the radio at this point as most of the case and other boards involved are long gone.
I might be able to get the amp powered just by plugging it in as is and figuring out where to tap in to input and speaker pins.