SC DSP Musicolour

[Bob Parker]

Don McKenzie wrote:

I have been paranoid about backups since my wife unplugged the power to
the TRS-80 in March 1978, after I had invested about 8 hours into a
program. She only wanted to plug in a double adapter, so she could get a
bit of ironing done I failed to write a copy to audio tape before
the damage was done.

I know the feeling. :-(
Wow - audio tapes takes me back to the DSE VZ200. Even if you did
save it to tape, it was often hit & miss getting it back into the
computer. All that fiddling with volume settings and tearing out of hair...

When USB V2 came along, it was fast enough to use for my dual backup
system, however I have lost many external drives in the process, so I
have to agree with you Bob, regarding external 3.5" drives.

Did they fail due to physical accidents, or just fail by
themselves? A lot of user reviews of big external 3.5" drives mention
the USB -> SATA interface board in the box dying, sometimes with
considerable amounts of smoke involved.

Seeing the 2.5" more robust, notebook drives dropping in price, and
increasing in capacity, made me think about them as a new potential
backup system.

These days, once a week I save a compressed full image of my main
drive to the new 500GB internal drive + the 80GB external which is
stored in a safe place. Crucial day-to-day stuff gets backed up on
DVD-RW. So far I haven't needed it ... fingers crossed.

But the first drive I tried was a Maxtor, and I found that it really
takes some grunt in the 5V department to fire up.

Am now trying an nice little LACIE which so far has been humming away
nicely, usually on one USB port.

Apparently LaCie just installs whatever drives they can get, into
their own packages. I read that they often use Samsungs.

 

[David L. Jones]

On May 30, 12:59 pm, "Mr.T" <MrT@home> wrote:

"David L. Jones" <altz...@gmail.com> wrote in messagenews:483e8f37$1@dnews.tpgi.com.au...

Anyone want to play spot the glaring error in the USB power injector
project?

You mean apart from the fact that it's cheaper and easier to just buy a
powered USB hub?

Another recent project that falls under that category is the dsPIC
programmer.
You can buy a genuine Microchip PICkit2 programmer for under $40, and
it supports all the PIC ranges, including the dsPIC. And if you need
the ZIF socket (who needs to with ICSP?) simply wire one up.
Add to that it's USB powered, can even power your (low power) project,
can double as a 3 channel 1MS/s logic analyser, and integrates into
MPLAB
Makes the SC project look very silly indeed. The space would have been
better served reviewing the PICkit2

Dave.

 

[Don McKenzie]

I know the feeling. :-(
Wow - audio tapes takes me back to the DSE VZ200. Even if you did
save it to tape, it was often hit & miss getting it back into the
computer. All that fiddling with volume settings and tearing out of hair...

I ripped the roms out of the VZ200 and decoded them. Almost an excact
copy of the TRS-80 with the obvious alterations to suit the hardware.
I then re-wrote them a little to suit a few mods I did.

When USB V2 came along, it was fast enough to use for my dual backup
system, however I have lost many external drives in the process, so I
have to agree with you Bob, regarding external 3.5" drives.

Did they fail due to physical accidents, or just fail by
themselves? A lot of user reviews of big external 3.5" drives mention
the USB -> SATA interface board in the box dying, sometimes with
considerable amounts of smoke involved.

failed by themselves. Sometimes drives, sometimes electronics. I think I
only found one that was nicely vented and with a fan. Was an ATA/SATA
i/f. That one is still going.

Apparently LaCie just installs whatever drives they can get, into
their own packages. I read that they often use Samsungs.

OK, thanks Bob.
After the mention of the LACIE, (Yes LaCie) I just tried the single
cable on powered and un-powered hubs to remind me. Un-powered, software
recognizes new hardware, but doesn't specify device, and it can't be found.
Powered, it flies right into it, and announces itself, no drama.

On my baby EEE PC's, it needs two ports to power it up.


Don...


--
Don McKenzie

Site Map: http://www.dontronics.com/sitemap
E-Mail Contact Page: http://www.dontronics.com/email

Intelligent 2.83" AMOLED with touch screen for micros:
http://www.dontronics-shop.com/product.php?productid=16699

 

[Don McKenzie]

David L. Jones wrote:

These days, once a week I save a compressed full image of my main
drive to the new 500GB internal drive + the 80GB external which is
stored in a safe place. Crucial day-to-day stuff gets backed up on
DVD-RW. So far I haven't needed it ... fingers crossed.

As well as multiple hard drives and CD archives etc, I automatically
back up important folders (photos, documents, project files etc) to my
FTP server in the US that has unlimited space. Nice'n'easy with the
incremental backup feature, only files that have changed are copied.
I use the free Cobian Backup 8 software
http://www.educ.umu.se/~cobian/cobianbackup.htm
Dave.

Both good ideas. Diverify, little like the old super fund. A few bob
each way. My two backup drives, one lives in a fireproof safe, the other
next to the PC, and they change over daily.

I always have a drive with files about 3 months old, off site, and as
most of my files these days are in web based shopping carts, they live
on line, and auto backed up every 4 hours to another server by my US host.

I use Acronis for local backup software, and always travel with a full
disk image of my main PC and notebook, in the notebook bag.

Don...


--
Don McKenzie

Site Map: http://www.dontronics.com/sitemap
E-Mail Contact Page: http://www.dontronics.com/email

Intelligent 2.83" AMOLED with touch screen for micros:
http://www.dontronics-shop.com/product.php?productid=16699

 

[David L. Jones]

On May 30, 3:09 pm, Bob Parker <bobp.deletet...@bluebottle.com> wrote:

Don McKenzie wrote:

I have been paranoid about backups since my wife unplugged the power to
the TRS-80 in March 1978, after I had invested about 8 hours into a
program. She only wanted to plug in a double adapter, so she could get a
bit of ironing done I failed to write a copy to audio tape before
the damage was done.

I know the feeling. :-(
Wow - audio tapes takes me back to the DSE VZ200. Even if you did
save it to tape, it was often hit & miss getting it back into the
computer. All that fiddling with volume settings and tearing out of hair...

When USB V2 came along, it was fast enough to use for my dual backup
system, however I have lost many external drives in the process, so I
have to agree with you Bob, regarding external 3.5" drives.

Did they fail due to physical accidents, or just fail by
themselves? A lot of user reviews of big external 3.5" drives mention
the USB -> SATA interface board in the box dying, sometimes with
considerable amounts of smoke involved.

Seeing the 2.5" more robust, notebook drives dropping in price, and
increasing in capacity, made me think about them as a new potential
backup system.

These days, once a week I save a compressed full image of my main
drive to the new 500GB internal drive + the 80GB external which is
stored in a safe place. Crucial day-to-day stuff gets backed up on
DVD-RW. So far I haven't needed it ... fingers crossed.

As well as multiple hard drives and CD archives etc, I automatically
back up important folders (photos, documents, project files etc) to my
FTP server in the US that has unlimited space. Nice'n'easy with the
incremental backup feature, only files that have changed are copied.
I use the free Cobian Backup 8 software
http://www.educ.umu.se/~cobian/cobianbackup.htm

Dave.

 

[Rheilly Phoull]

Phil Allison wrote:

"Andy Wood"
"David L. Jones"
That ain't it, but nice guess, thanks for playing.
You are welcome to try again.

Can anyone else beat Don to the punch?
To have any chance in this game I would have to rush out and buy the
latest SC.

Just how much is Leo paying you?


** LOL !!

I have put a scan of the schematic on ABSE for you.


.... Phil


The transistor to hold off the FET seems a about to me.

Rheilly P

 

[David L. Jones]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:6a9edqF370u75U1@mid.individual.net...

"Andy Wood"
"David L. Jones"

That ain't it, but nice guess, thanks for playing.
You are welcome to try again.

Can anyone else beat Don to the punch?

To have any chance in this game I would have to rush out and buy the
latest SC.

Just how much is Leo paying you?


** LOL !!

I have put a scan of the schematic on ABSE for you.

For those without easy usenet binary access:
http://www.alternatezone.com/stuff/USBsupply.jpg

Come on, step right up, spot the mistake in the circuit!

Dave.

 

[Don McKenzie]

David L. Jones wrote:

Come on, step right up, spot the mistake in the circuit!

Dave.

can I have another go Dave?
Please can I, can I? Pretty please

Strangely, it is obvious when you stop looking too hard.

Don...



--
Don McKenzie

Site Map: http://www.dontronics.com/sitemap
E-Mail Contact Page: http://www.dontronics.com/email

Intelligent 2.83" AMOLED with touch screen for micros:
http://www.dontronics-shop.com/product.php?productid=16699

 

[Don McKenzie]

Don McKenzie wrote:

David L. Jones wrote:

Come on, step right up, spot the mistake in the circuit!

Dave.

can I have another go Dave?
Please can I, can I? Pretty please

Strangely, it is obvious when you stop looking too hard.

Don...

In fact, there is a wee bit of a mess, and I think it all came about
because of what I said in my first guess.

You need to read the text of the article to knit it together.

Don...


--
Don McKenzie

Site Map: http://www.dontronics.com/sitemap
E-Mail Contact Page: http://www.dontronics.com/email

Intelligent 2.83" AMOLED with touch screen for micros:
http://www.dontronics-shop.com/product.php?productid=16699

 

[Don McKenzie]

Al Borowski wrote:

6V in - .7V across the diode = not enough headroom for the regulator?

Oops, it's a Schottky. So @ 1A, the LDO needs 5.5V, but the specified
diode will typically drop .6V - which means out of 6V, the regulator
gets 5.4V (slightly less, given the FET drop). Still not the greatest
design for 1A. How much current is this thing supposed to supply?

I get the feeling I'm missing something obvious.

Cheers,

Al

I would suggest there is nothing wrong with the mechanics Al, even
though it may appear marginal. I went down the same path initially.

I doubt that the drive would draw an amp.

But the original design problem was excessing heat, so changes were made.

A clue:
I'm putting my money on the result of those changes not being completed
correctly.

Don...


--
Don McKenzie

Site Map: http://www.dontronics.com/sitemap
E-Mail Contact Page: http://www.dontronics.com/email

Intelligent 2.83" AMOLED with touch screen for micros:
http://www.dontronics-shop.com/product.php?productid=16699

 

[Don McKenzie]

Al Borowski wrote:

But the original design problem was excessing heat, so changes were made.

A clue:
I'm putting my money on the result of those changes not being completed
correctly.

OK, please keep in mind I have only seen the scan, so I have no idea
what this thing is supposed to do. But here's my guess:

It used to use a higher voltage power supply and a 7805. The '05 got
too hot, so they changed to an LDO and a 5V supply. But they forgot to
read the datasheet correctly. It states

"The minimum output capacitance required to maintain stability is 22
ľF (this value may be increased without limit)"

And we have a .1uF cap on the output, so the whole thing may
oscillate.

Do I win a prize?

Cheers,

Al

Does Al win a prize Dave?

Don...




--
Don McKenzie

Site Map: http://www.dontronics.com/sitemap
E-Mail Contact Page: http://www.dontronics.com/email

Intelligent 2.83" AMOLED with touch screen for micros:
http://www.dontronics-shop.com/product.php?productid=16699

 

[Al Borowski]

For those without easy usenet binary access:http://www.alternatezone.com/stuff/USBsupply.jpg

Come on, step right up, spot the mistake in the circuit!

6V in - .7V across the diode = not enough headroom for the regulator?

Cheers,

Al

 

[Al Borowski]

6V in - .7V across the diode = not enough headroom for the regulator?

Oops, it's a Schottky. So @ 1A, the LDO needs 5.5V, but the specified
diode will typically drop .6V - which means out of 6V, the regulator
gets 5.4V (slightly less, given the FET drop). Still not the greatest
design for 1A. How much current is this thing supposed to supply?

I get the feeling I'm missing something obvious.

Cheers,

Al

 

[Al Borowski]

But the original design problem was excessing heat, so changes were made.

A clue:
I'm putting my money on the result of those changes not being completed
correctly.

OK, please keep in mind I have only seen the scan, so I have no idea
what this thing is supposed to do. But here's my guess:

It used to use a higher voltage power supply and a 7805. The '05 got
too hot, so they changed to an LDO and a 5V supply. But they forgot to
read the datasheet correctly. It states

"The minimum output capacitance required to maintain stability is 22
ľF (this value may be increased without limit)"

And we have a .1uF cap on the output, so the whole thing may
oscillate.

Do I win a prize?

Cheers,

Al

 

[Eeyore]

Al Borowski wrote:

For those without easy usenet binary access:http://www.alternatezone.com/stuff/USBsupply.jpg

Come on, step right up, spot the mistake in the circuit!

6V in - .7V across the diode = not enough headroom for the regulator?

It's a schottky. 1N5817 would be better though.

Graham

 

[Eeyore]

Al Borowski wrote:

It used to use a higher voltage power supply and a 7805. The '05 got
too hot, so they changed to an LDO and a 5V supply. But they forgot to
read the datasheet correctly. It states

"The minimum output capacitance required to maintain stability is 22
ľF (this value may be increased without limit)"

And we have a .1uF cap on the output, so the whole thing may
oscillate.

Do I win a prize?

I didn't get a prize on a.b.s.e for saying that ! :-(

Graham

 

[David L. Jones]

"Don McKenzie" <5V@2.5A> wrote in message
news:6acmj4F35gnipU1@mid.individual.net...

Al Borowski wrote:
But the original design problem was excessing heat, so changes were
made.

A clue:
I'm putting my money on the result of those changes not being completed
correctly.

OK, please keep in mind I have only seen the scan, so I have no idea
what this thing is supposed to do. But here's my guess:

It used to use a higher voltage power supply and a 7805. The '05 got
too hot, so they changed to an LDO and a 5V supply. But they forgot to
read the datasheet correctly. It states

"The minimum output capacitance required to maintain stability is 22
ľF (this value may be increased without limit)"

And we have a .1uF cap on the output, so the whole thing may
oscillate.

Do I win a prize?

Cheers,

Al

Does Al win a prize Dave?

Al does indeed win the prize!
But I suspect Don knew all along...

Classic mistake with LDO's, and this one in particular is notorious for it.
Yes, 22uF minium is required, so there is a very high likelihood this sucker
is going to oscillate.
So not only did the previous design have an error (overheating), the new one
has a nasty one too. All on the simplist of circuits, unbelievable. The text
even says the 0.1uF is there to ensure stability!

Dave.

 

[Eeyore]

"David L. Jones" wrote:

"Don McKenzie" <5V@2.5A> wrote in message
Al Borowski wrote:
But the original design problem was excessing heat, so changes were
made.

A clue:
I'm putting my money on the result of those changes not being completed
correctly.

OK, please keep in mind I have only seen the scan, so I have no idea
what this thing is supposed to do. But here's my guess:

It used to use a higher voltage power supply and a 7805. The '05 got
too hot, so they changed to an LDO and a 5V supply. But they forgot to
read the datasheet correctly. It states

"The minimum output capacitance required to maintain stability is 22
ľF (this value may be increased without limit)"

And we have a .1uF cap on the output, so the whole thing may
oscillate.

Do I win a prize?

Cheers,

Al

Does Al win a prize Dave?

Al does indeed win the prize!
But I suspect Don knew all along...

Classic mistake with LDO's, and this one in particular is notorious for it.
Yes, 22uF minium is required, so there is a very high likelihood this sucker
is going to oscillate.
So not only did the previous design have an error (overheating), the new one
has a nasty one too. All on the simplist of circuits, unbelievable. The text
even says the 0.1uF is there to ensure stability!

It's a classic error wihen people drop in LDO regulators because it's a slowish
pnp collector output instead of an npn emitter output. For similar reasons note
that 79xx's also require more local decoupling than 78xx's.

Graham

 

[Franc Zabkar]

On Sat, 31 May 2008 03:08:08 -0700 (PDT), Al Borowski
<al.borowski@gmail.com> put finger to keyboard and composed:

But the original design problem was excessing heat, so changes were made.

A clue:
I'm putting my money on the result of those changes not being completed
correctly.

OK, please keep in mind I have only seen the scan, so I have no idea
what this thing is supposed to do. But here's my guess:

It used to use a higher voltage power supply and a 7805.

Spot on! The original design required 9V AC/DC and used a 7805.

USB Power Injector (Issue 193, Published: 18 October, 2004):
http://www.siliconchip.com.au/cms/A_102685/article.html
http://us1.webpublications.com.au/static/images/articles/i1026/102685_5mg.jpg

The '05 got
too hot, so they changed to an LDO and a 5V supply.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[dmm]

On Sat, 31 May 2008 17:51:20 +1000, "David L. Jones" <altzone@gmail.com> wrote:

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:6a9edqF370u75U1@mid.individual.net...

"Andy Wood"
"David L. Jones"

That ain't it, but nice guess, thanks for playing.
You are welcome to try again.

Can anyone else beat Don to the punch?

To have any chance in this game I would have to rush out and buy the
latest SC.

Just how much is Leo paying you?


** LOL !!

I have put a scan of the schematic on ABSE for you.

For those without easy usenet binary access:
http://www.alternatezone.com/stuff/USBsupply.jpg

Come on, step right up, spot the mistake in the circuit!

Dave.

I don't know about you guys, but I haven't seen too many PC motherboards with USB type B outputs.

Type A, yes, but not Type B.

dmm