Isolated, regulated, toroidal step down transformer AC power supply design.

9 VAC in, 15 VDC out, after regulation.

How is that NOT a voltage DOUBLING design?

Or is it because you believe that such a design is impossible?

It must be >> Some of my assumptions may well have been incorrect, but they are ALL

With great difficulty.

However, it is a problem with the thread structure of most readers, not with the order of my statements.

Finally - a little bit of clarity in an ocean of half-truths, paranoid secrecy and babble about 'Philophiles'. :-( I suppose it would be hoping for a miracle to get an answer to the next question a technician would ask:

Did it have this problem from the very beginning?

Have you measured any voltages within the powers supply yet, as advised by many people here? This is something you should have done before starting to arbitrarily replacing capacitors.

Oh, and thanks for the term "recapping" I hadn't heard it used in such a manner before.

Whatever, Poxy. It's a term I use. You are welcome to make whatever of it you will.

No I haven't measured it yet. I haven't even had the lid off, YET!

I th>> I can see your questions Bob.

"Poxy"

** Must be what fools do in panic after the Genie escapes from the bottle.

....... Phil

Surely you had the lid off when you went all "recap" on it?

If the only power coming into the device is from the output of a 9V AC plugpack, it is quite safe to poke about inside while it's on, but you need to be careful not to short-circuit anything with your meter probes.

As I've mentioned before, you need to check the incoming AC voltage, the DC voltage at the input of each regulator relative to its ground pin, and the output of each regulator. You should check the pinouts of the regulators from their respective datasheets.

While I realise the problem only presents itself occasionally, getting steady-state measurements will give us some idea of how the power supply is likely to behave as the supply voltage varies.

No it wouldn't. You are a twit and I give up. I'll just watch from now on, or maybe killfile you and this absurd thread.

That's not what you have got. It's what you think you have got. You have 30VDC out (+/-15VDC).

You have a wall wart transformer with poor load regulation. I'm guessing it's about 15VAC you have coming out of your wall wart. I also suspect the original design is relying on this to work.

Try taking some measurements rather than quoting the info that's printed on it.

pffffft... The CLAIM to the possession of a SPECIFIC piece of knowledge (or the lack of it) does not equate to expertise (or the lack of it).

Shoddy post, Jasen.

I think I already answered it Bob. Twice, in fact.

What is your obsessi>> I grew tired of this thread a short time ago.

"swanny"

** Nope.

From the copious schizoid ramblings of this delusional bush maggot - I now surmise the PSU he has operates from a nominal 9 volt AC plug pack with a couple of amps capacity. One side of the secondary goes directly to circuit ground.

Then come four diodes and four electros ( values not described) that act together as " charge pump" voltage multipliers. This will generate maybe

+/- 23 volts DC ( plus ample ripple) at the input to the 7815 / 7915 regs.

Load regulation will be mediocre - at best.

What he ought to do is get a new AC supply tranny ( toroidal is OK) with a

18-0-18 volt secondary of circa 2.5 amps and use a bridge rectifier and filter electros of say 6,800 uF or a parallel combo to that same sort of value.

This will have good load regulation and low ripple.

But you will never tell HIM that !!

...... Phil

You haven't clearly answered anything. What I can't understand is why people (even Phil) are continuing to try to give you useful advice despite your arrogant smug delusional attitude and total absense of knowledge of what you're babbling about. What a waste of bandwidth.

**No, it is not irrlevant.

**Why do you specify a toroidal transformer? **No, you have not. You have STILL not answered the many important questions I've asked either.

Here's one:

What is the input Voltage on the regulators?

--
Trevor Wilson
www.rageaudio.com.au

"Trevor Wilson"

** Wake up - TW !!!

The schizo bush maggot has not even got a DMM.

....... Phil

Even if he did, he'd probably try to measure how many ohms were coming out of his plugpack.

.noitasrevnoc a fo wolf lacigol eht wollof ot drah ti sekam ylno gnitsop poT

When you read a book, you start at page one and normally read from the top left to the bottom right. An author will sell next person follows on from there, not the answer first then the question. scattered throughout the rest of the book. That is why top posting is totally illogical. eg. someone poses a question, the very few books if he wrote the beginning in chapter 15, then the ending in chapter 2 with the body of the story spread and