sci.electronics.repair@googlegroups.com

Today's topics:

* Mixing 4 audio channels to 3? - 12 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/a9c921002b2ed750?hl=en
* unassembling external drive enclosure - 7 messages, 6 authors
http://groups.google.com/group/sci.electronics.repair/t/d976fe30b90ef802?hl=en
* broke my own circuit - 4017 decade/Johnson counter - 3 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/33e2c80674da2af0?hl=en
* home-brew Freon TF substitutes? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/f66a71610e41b61d?hl=en
* Peavey Valve King 212 - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/ec305ab9075c184c?hl=en
* issue with electret condenser mic - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/0f83e591aedae6bd?hl=en

==============================================================================
TOPIC: Mixing 4 audio channels to 3?
http://groups.google.com/group/sci.electronics.repair/t/a9c921002b2ed750?hl=en
==============================================================================

== 1 of 12 ==
Date: Tues, Oct 25 2011 11:59 pm
From: DaveC

If I'm on the right track, what are the suggested values for resistors?

Thahks.

== 2 of 12 ==
Date: Wed, Oct 26 2011 8:50 am
From: NT

On Oct 26, 7:58 am, DaveC <inva...@invalid.net> wrote:
> I want to connect the audio out (headphone jack) of 2 computer sound cards to
> a desktop & woofer speaker-amp combination. (The original input was via USB
> only and I'm modifying this for analog audio input.)
>
> This is my guess at the necessary resistors to mix down these 4 outputs to
> the 3 inputs in the amplifier (L, R, sub):
>
> <http://i41.tinypic.com/97mpud.jpg>

Lose Rs 1-4, keep 5-8, lose R11, and lose C1,2,3, then itll be good.

NT

== 3 of 12 ==
Date: Wed, Oct 26 2011 9:09 am
From: spam@spam.com (Don Pearce)

On Wed, 26 Oct 2011 08:50:55 -0700 (PDT), NT <meow2222@care2.com>
wrote:

>On Oct 26, 7:58 am, DaveC <inva...@invalid.net> wrote:
>> I want to connect the audio out (headphone jack) of 2 computer sound cards to
>> a desktop & woofer speaker-amp combination. (The original input was via USB
>> only and I'm modifying this for analog audio input.)
>>
>> This is my guess at the necessary resistors to mix down these 4 outputs to
>> the 3 inputs in the amplifier (L, R, sub):
>>
>> <http://i41.tinypic.com/97mpud.jpg>
>
>Lose Rs 1-4, keep 5-8, lose R11, and lose C1,2,3, then itll be good.
>
>
>NT

Is there something wrong with my browser? I can't see any of these
component references. Actually I see what you mean. One problem here
is that R9 and R10 are going to cause crosstalk. Without some active
electronics there is no way around that apart from taking the sub from
one channel only. This is actually quite common.

d

== 4 of 12 ==
Date: Wed, Oct 26 2011 10:04 am
From: DaveC

> Is there something wrong with my browser? I can't see any of these
> component references.

Sorry. They didn't make onto the jpg file. Added here:

<http://i40.tinypic.com/5ets9w.jpg>

> Actually I see what you mean. One problem here
> is that R9 and R10 are going to cause crosstalk. Without some active
> electronics there is no way around that apart from taking the sub from
> one channel only. This is actually quite common.
> d

OK, can do that.

Suggested values for resistors?

Thanks.

== 5 of 12 ==
Date: Wed, Oct 26 2011 10:10 am
From: DaveC

> Lose Rs 1-4, keep 5-8, lose R11, and lose C1,2,3, then itll be good.
> NT

Callouts added:

<http://i40.tinypic.com/5ets9w.jpg>

R11 provides some adjustment for sub. Otherwise no way to have any difference
between L & R channel volume and sub volume.

The caps are suggested on the data sheet example:

<http://i40.tinypic.com/5ets9w.jpg>

Why would you do away with them?

What values for the resistors do you suggest?

Thanks.

== 6 of 12 ==
Date: Wed, Oct 26 2011 10:49 am
From: spam@spam.com (Don Pearce)

On Wed, 26 Oct 2011 10:10:12 -0700, DaveC <invalid@invalid.net> wrote:

>> Lose Rs 1-4, keep 5-8, lose R11, and lose C1,2,3, then itll be good.
>> NT
>
>Callouts added:
>
><http://i40.tinypic.com/5ets9w.jpg>
>
>R11 provides some adjustment for sub. Otherwise no way to have any difference
>between L & R channel volume and sub volume.
>
>The caps are suggested on the data sheet example:
>
><http://i40.tinypic.com/5ets9w.jpg>
>
>Why would you do away with them?
>
>What values for the resistors do you suggest?
>
>Thanks.

For that particular circuit with that chip, the caps are necessary
because those inputs are not at ground potential. If you are feeding
normal hi fi unit inputs the caps aren't needed. Resistor values
around 5 to 10 k would be what you need.

d

== 7 of 12 ==
Date: Wed, Oct 26 2011 11:18 am
From: DaveC

> For that particular circuit with that chip, the caps are necessary
> because those inputs are not at ground potential. If you are feeding
> normal hi fi unit inputs the caps aren't needed. Resistor values
> around 5 to 10 k would be what you need.

And the value for the potentiometer?

Thanks.

== 8 of 12 ==
Date: Wed, Oct 26 2011 11:26 am
From: spam@spam.com (Don Pearce)

On Wed, 26 Oct 2011 11:18:39 -0700, DaveC <invalid@invalid.net> wrote:

>> For that particular circuit with that chip, the caps are necessary
>> because those inputs are not at ground potential. If you are feeding
>> normal hi fi unit inputs the caps aren't needed. Resistor values
>> around 5 to 10 k would be what you need.
>
>And the value for the potentiometer?
>
That depends entirely on the input impedance of the subwoofer. You
could try a 100k pot and connect it as a normal volume control - one
end to the incoming signal, the other end to ground and the slider to
the subwoofer.

d

== 9 of 12 ==
Date: Wed, Oct 26 2011 11:52 am
From: DaveC

> That depends entirely on the input impedance of the subwoofer. You
> could try a 100k pot and connect it as a normal volume control - one
> end to the incoming signal, the other end to ground and the slider to
> the subwoofer.
>
> d

The data sheet says that the 2 single-ended inputs (R & L) are 50K impedance.
The bridge-tied load ("BTL") input -- used for the sub -- is 25K impedance.

Does this suggest any change to your recommendation of a 100K pot tied to
ground?

Thanks.

== 10 of 12 ==
Date: Wed, Oct 26 2011 12:20 pm
From: spam@spam.com (Don Pearce)

On Wed, 26 Oct 2011 11:52:49 -0700, DaveC <invalid@invalid.net> wrote:

>> That depends entirely on the input impedance of the subwoofer. You
>> could try a 100k pot and connect it as a normal volume control - one
>> end to the incoming signal, the other end to ground and the slider to
>> the subwoofer.
>>
>> d
>
>The data sheet says that the 2 single-ended inputs (R & L) are 50K impedance.
>The bridge-tied load ("BTL") input -- used for the sub -- is 25K impedance.
>
>Does this suggest any change to your recommendation of a 100K pot tied to
>ground?
>
>Thanks.

No, that would be about right.

d

== 11 of 12 ==
Date: Wed, Oct 26 2011 1:03 pm
From: moroney@world.std.spaamtrap.com (Michael Moroney)

spam@spam.com (Don Pearce) writes:

>On Wed, 26 Oct 2011 08:50:55 -0700 (PDT), NT <meow2222@care2.com>
>wrote:

>>On Oct 26, 7:58 am, DaveC <inva...@invalid.net> wrote:
>>> I want to connect the audio out (headphone jack) of 2 computer sound cards to
>>> a desktop & woofer speaker-amp combination. (The original input was via USB
>>> only and I'm modifying this for analog audio input.)
>>>
>>> This is my guess at the necessary resistors to mix down these 4 outputs to
>>> the 3 inputs in the amplifier (L, R, sub):
>>>
>>> <http://i41.tinypic.com/97mpud.jpg>
>>
>>Lose Rs 1-4, keep 5-8, lose R11, and lose C1,2,3, then itll be good.
>>
>>
>>NT

>Is there something wrong with my browser? I can't see any of these
>component references. Actually I see what you mean. One problem here
>is that R9 and R10 are going to cause crosstalk. Without some active
>electronics there is no way around that apart from taking the sub from
>one channel only. This is actually quite common.

I don't see component references, either. However, assuming R1-R4 are
the resistors from the inputs to ground, they may be necessary to provide
a proper impedance to the source driving them.

To reduce crosstalk, I'd replace the two resistors from the 220nF
cap junctions to the pot with four resistors from each of the four inputs
to the pot. Presumably, the output impedance of the amps is low compared
to the resistors reducing crosstalk.

For mixing signals there is a method using amps and feedback where the
connection between multiple sources is at a virtual ground, eliminating
crosstalk.

== 12 of 12 ==
Date: Wed, Oct 26 2011 1:25 pm
From: NT

On Oct 26, 5:09 pm, s...@spam.com (Don Pearce) wrote:
> On Wed, 26 Oct 2011 08:50:55 -0700 (PDT), NT <meow2...@care2.com>
> wrote:
>
> >On Oct 26, 7:58 am, DaveC <inva...@invalid.net> wrote:
> >> I want to connect the audio out (headphone jack) of 2 computer sound cards to
> >> a desktop & woofer speaker-amp combination. (The original input was via USB
> >> only and I'm modifying this for analog audio input.)
>
> >> This is my guess at the necessary resistors to mix down these 4 outputs to
> >> the 3 inputs in the amplifier (L, R, sub):
>
> >> <http://i41.tinypic.com/97mpud.jpg>
>
> >Lose Rs 1-4, keep 5-8, lose R11, and lose C1,2,3, then itll be good.
>
> >NT
>
> Is there something wrong with my browser? I can't see any of these
> component references. Actually I see what you mean. One problem here
> is that R9 and R10 are going to cause crosstalk. Without some active
> electronics there is no way around that apart from taking the sub from
> one channel only. This is actually quite common.
>
> d

I was hinting that the OP might decide to add numbers to the
components, otherwise its sufficiently tedious to talk about them that
people often just wont bother.

Yes the caps are necessary, but for the amp IC, not for the mixer.
House them together and its the same difference, house them apart and
the distiction matters.

NT

==============================================================================
TOPIC: unassembling external drive enclosure
http://groups.google.com/group/sci.electronics.repair/t/d976fe30b90ef802?hl=en
==============================================================================

== 1 of 7 ==
Date: Wed, Oct 26 2011 3:42 am
From: "Mark Zacharias"

"Ninho" <don't.use!@this.is.invalid> wrote in message
news:XnF9F8987F397CBBG6R6C1N@193.252.117.183...
> Hi! Got a problem, which I've been advised to submit to this Group's
> experienced users. Please pardon me if I made an error posting, also,
> bear with less than adequate English !
>
> So, a 6/7 years old 80-gigabyte disk in an external USB 2.0
> enclosure has failed me. I suspect the drive itself could be OK but
> the USB interface or other electronics/connectics of the case might
> have fail (it had been acting weird sometimes)
>
> Now I would like to separate the drive from this enclosure and
> connect it straight to the MoBoard for testing.
>
> Brand stamped on the pretty, sturdy case is "QPS multimedia" ("made
> in China"). Disk inside is Maxtor 80 Gb, probably pATA.
>
> Disk + enclosure came as a unit, and the problem is, I can't seem to
> be able to disassemble it even after removing screws :=(
> I don't think I've missed any hidden screws.
>
> The disk itself is a 80Gb Maxtor, I assume pATA.
>
> Googling hasn't served very much, nor did Youtube help. The "QPS"
> brand is no longer manufacturing those articles it seems.
>
> I hope someone can point me to a site with instructions or hints for
> disassembly.
>
> --
> Ninho

Does it utilize an external power supply adaptor? My Western Digital MyBook
developed bad caps in the power supply.

Mark Z.

== 2 of 7 ==
Date: Wed, Oct 26 2011 6:14 am
From: Steph

"Mark Zacharias" wrote:
> "Ninho" <don't.use!@this.is.invalid> wrote in message
>> So, a 6/7 years old 80-gigabyte disk in an external USB 2.0
>> enclosure has failed me. I suspect the drive itself could be OK
>> but the USB interface or other electronics/connectics of the case
>> might have fail (it had been acting weird sometimes)

> Does it utilize an external power supply adaptor? My Western
> Digital MyBook developed bad caps in the power supply.

It does indeed - the possibility of a bad power supply hadn't even
traversed my mind ! The PS connects to the main unit using a DIN plug,
which to this layman seems a non standard arrangement and I don't know
where to find a spare.

--
Ninho

== 3 of 7 ==
Date: Wed, Oct 26 2011 6:14 am
From: chrisj.doran%proemail.co.uk@gtempaccount.com

On Oct 26, 11:42 am, "Mark Zacharias" <mark_zachar...@labolgcbs.net>
wrote:
> "Ninho" <don't.u...@this.is.invalid> wrote in message
>
> news:XnF9F8987F397CBBG6R6C1N@193.252.117.183...
>
>
>
>
>
> > Hi! Got a problem, which I've been advised to submit to this Group's
> > experienced users. Please pardon me if I made an error posting, also,
> > bear with less than adequate English !
>
> > So, a 6/7 years old 80-gigabyte disk in an external USB 2.0
> > enclosure has failed me. I suspect the drive itself could be OK but
> > the USB interface or other electronics/connectics of the case might
> > have fail (it had been acting weird sometimes)
>
> > Now I would like to separate the drive from this enclosure and
> > connect it straight to the MoBoard for testing.
>
> > Brand stamped on the pretty, sturdy case is "QPS multimedia" ("made
> > in China"). Disk inside is Maxtor 80 Gb, probably pATA.
>
> > Disk + enclosure came as a unit, and the problem is, I can't seem to
> > be able to disassemble it even after removing screws :=(
> > I don't think I've missed any hidden screws.
>
> > The disk itself is a 80Gb Maxtor, I assume pATA.
>
> > Googling hasn't served very much, nor did Youtube help. The "QPS"
> > brand is no longer manufacturing those articles it seems.
>
> > I hope someone can point me to a site with instructions or hints for
> > disassembly.
>
> > --
> > Ninho
>
> Does it utilize an external power supply adaptor? My Western Digital MyBook
> developed bad caps in the power supply.
>
> Mark Z.- Hide quoted text -
>
> - Show quoted text -

Same here with my ATMT HD363n -- I've got through two of the supplied
power supplies and now using something beefier. "Acting weird
sometimes" (partial file copies and file renaming failing) followed by
total failure is a good description of the symptoms. I think I'm
having a similar problem with my modem/router wallwart.

Chris

== 4 of 7 ==
Date: Wed, Oct 26 2011 7:40 am
From: Dave M

On 26 Oct 2011 13:14:34 GMT, Steph <pas.de.mail@serveur.invalid> wrote:

>"Mark Zacharias" wrote:
>> "Ninho" <don't.use!@this.is.invalid> wrote in message
>>> So, a 6/7 years old 80-gigabyte disk in an external USB 2.0
>>> enclosure has failed me. I suspect the drive itself could be OK
>>> but the USB interface or other electronics/connectics of the case
>>> might have fail (it had been acting weird sometimes)
>
>> Does it utilize an external power supply adaptor? My Western
>> Digital MyBook developed bad caps in the power supply.
>
>
>It does indeed - the possibility of a bad power supply hadn't even
>traversed my mind ! The PS connects to the main unit using a DIN plug,
>which to this layman seems a non standard arrangement and I don't know
>where to find a spare.

What is the make and model of the drive (not the drive itself, but the
whole assembly)?
I've had to replace the power supplies for two of my external drives,
one Iomega and one Western Digital. It's not too difficult to find
replacement power supplies. I found very reasonable power supplies on
Amazon. I bought Hootoo Laptop Battery Chargers, which seem to work
well and have been reliable for over a year. Hootoo makes power
supplies for many makes and models.

Cheers,
Dave M

== 5 of 7 ==
Date: Wed, Oct 26 2011 8:21 am
From: Ninho

Dave M <masondg4499@comcast.net> écrivait

> On 26 Oct 2011 13:14:34 GMT, Steph <pas.de.mail@serveur.invalid>

That Steph above would be me

> asked:

> What is the make and model of the drive (not the drive itself, but
> the whole assembly)?

"QPS Multimedia" "USB 2.0" "Made in China" and a barcode and serial
number is all identification I can find on the case. External
dimensions (centimetres) are about 22x13x4.

It appears QPS doesn't manufacture or distribute hard disk assemblies
any more.

> I've had to replace the power supplies for two of my external
> drives, one Iomega and one Western Digital. It's not too
> difficult to find replacement power supplies. I found very
> reasonable power supplies on Amazon. I bought Hootoo Laptop
> Battery Chargers, which seem to work well and have been reliable
> for over a year. Hootoo makes power supplies for many makes and
> models.

Good to know, still I'd like to be able to get the drive out of the
stupid case first !
As for the power adapter again, its DIN-format connector is a dual
5V/12V output - 4 pins. Does this seem like a standard arrangement ?

--
Ninho

> Cheers,
> Dave M

== 6 of 7 ==
Date: Wed, Oct 26 2011 9:08 am
From: "Dave M"

Ninho wrote:
> Dave M <masondg4499@comcast.net> écrivait
>
>> On 26 Oct 2011 13:14:34 GMT, Steph <pas.de.mail@serveur.invalid>
>
> That Steph above would be me
>
>> asked:
>
>> What is the make and model of the drive (not the drive itself, but
>> the whole assembly)?
>
> "QPS Multimedia" "USB 2.0" "Made in China" and a barcode and serial
> number is all identification I can find on the case. External
> dimensions (centimetres) are about 22x13x4.
>
> It appears QPS doesn't manufacture or distribute hard disk assemblies
> any more.
>
>> I've had to replace the power supplies for two of my external
>> drives, one Iomega and one Western Digital. It's not too
>> difficult to find replacement power supplies. I found very
>> reasonable power supplies on Amazon. I bought Hootoo Laptop
>> Battery Chargers, which seem to work well and have been reliable
>> for over a year. Hootoo makes power supplies for many makes and
>> models.
>
> Good to know, still I'd like to be able to get the drive out of the
> stupid case first !
> As for the power adapter again, its DIN-format connector is a dual
> 5V/12V output - 4 pins. Does this seem like a standard arrangement ?
>
>
>> Cheers,
>> Dave M

Yeah, that's not an uncommon arrangement. My Iomega USB drive has such a
connector. If you can't find a suitable power supply, there is another good
alternative.
First thing you have to do is to determine the type of interface the disk
drive has (Parallel or Serial, ATA/IDE, etc.). Then buy an external USB
enclosure kit for the drive. The external drive enclosures come with the
power supply, the correct interface for the drive and the USB interface to
your PC. You just remove your drive from the existing enclosure, mount it
into the new enclosure and plug it in.
Ebay lists lots of them. Assuming that your hard drive is a 3.5" unit, try
this search:
http://www.ebay.com/dsc/i.html?_nkw=3.5%22+USB+External+%28IDE%2CSATA%29+Hard+Drive+Enclosure&_sacat=58058&_sop=1&_dmd=1&_odkw=3.5%22+USB+External+IDE+Hard+Drive+Enclosure&_osacat=58058&_trksid=p3286.c0.m270.l1313&LH_TitleDesc=1

Opening the case can be tedious. First, make sure that all the screws are
removed. Be sure to look under any labels on the case; there might be a
screw under it. The caase halves might slide apart rather than pop up.
Push the halves apart in opposite directions and pry them apart. If the
case halves are ultrasonically welded, you'll have to destroy the case to
get them apart. No big deal, since it will be discarded anyway, just be
careful not to damage the drive inside. Once inside, remove the mounting
screws and disconnect the cables. Remove the drive and place it into the
new enclosure. Fasten it with the correct hardware. Connect the cables,
put the enclosure together, plug it in, and you should be off & running.

Seagate now owns Maxtor, so you'll need to go to
http://www.seagate.com/www/en-us/support/ and find the datasheet for your
disk drive. That should give you the interface info you need to get the
right external enclosure kit. You should be able to find a good enclosure
kit on Ebay or Amazon. Prices vary; $15 - $50. Your chioce.

--
David
dgminala at mediacombb dot net

== 7 of 7 ==
Date: Wed, Oct 26 2011 9:16 am
From: Dave M

On Wed, 26 Oct 2011 11:08:20 -0500, "Dave M"
<dgminala4444@mediacombb.net> wrote:

>Ninho wrote:
>> Dave M <masondg4499@comcast.net> écrivait
>>
>>> On 26 Oct 2011 13:14:34 GMT, Steph <pas.de.mail@serveur.invalid>
>>
>> That Steph above would be me
>>
>>> asked:
>>
>>> What is the make and model of the drive (not the drive itself, but
>>> the whole assembly)?
>>
>> "QPS Multimedia" "USB 2.0" "Made in China" and a barcode and serial
>> number is all identification I can find on the case. External
>> dimensions (centimetres) are about 22x13x4.
>>
>> It appears QPS doesn't manufacture or distribute hard disk assemblies
>> any more.
>>
>>> I've had to replace the power supplies for two of my external
>>> drives, one Iomega and one Western Digital. It's not too
>>> difficult to find replacement power supplies. I found very
>>> reasonable power supplies on Amazon. I bought Hootoo Laptop
>>> Battery Chargers, which seem to work well and have been reliable
>>> for over a year. Hootoo makes power supplies for many makes and
>>> models.
>>
>> Good to know, still I'd like to be able to get the drive out of the
>> stupid case first !
>> As for the power adapter again, its DIN-format connector is a dual
>> 5V/12V output - 4 pins. Does this seem like a standard arrangement ?
>>
>>
>>> Cheers,
>>> Dave M
>
>Yeah, that's not an uncommon arrangement. My Iomega USB drive has such a
>connector. If you can't find a suitable power supply, there is another good
>alternative.
>First thing you have to do is to determine the type of interface the disk
>drive has (Parallel or Serial, ATA/IDE, etc.). Then buy an external USB
>enclosure kit for the drive. The external drive enclosures come with the
>power supply, the correct interface for the drive and the USB interface to
>your PC. You just remove your drive from the existing enclosure, mount it
>into the new enclosure and plug it in.
>Ebay lists lots of them. Assuming that your hard drive is a 3.5" unit, try
>this search:
>http://www.ebay.com/dsc/i.html?_nkw=3.5%22+USB+External+%28IDE%2CSATA%29+Hard+Drive+Enclosure&_sacat=58058&_sop=1&_dmd=1&_odkw=3.5%22+USB+External+IDE+Hard+Drive+Enclosure&_osacat=58058&_trksid=p3286.c0.m270.l1313&LH_TitleDesc=1
>
>Opening the case can be tedious. First, make sure that all the screws are
>removed. Be sure to look under any labels on the case; there might be a
>screw under it. The caase halves might slide apart rather than pop up.
>Push the halves apart in opposite directions and pry them apart. If the
>case halves are ultrasonically welded, you'll have to destroy the case to
>get them apart. No big deal, since it will be discarded anyway, just be
>careful not to damage the drive inside. Once inside, remove the mounting
>screws and disconnect the cables. Remove the drive and place it into the
>new enclosure. Fasten it with the correct hardware. Connect the cables,
>put the enclosure together, plug it in, and you should be off & running.
>
>Seagate now owns Maxtor, so you'll need to go to
>http://www.seagate.com/www/en-us/support/ and find the datasheet for your
>disk drive. That should give you the interface info you need to get the
>right external enclosure kit. You should be able to find a good enclosure
>kit on Ebay or Amazon. Prices vary; $15 - $50. Your chioce.

I should add that you should make sure that the kit you buy does indeed
contain all the necessary parts; case, interface, cables and power
supply. Also, make sure that it will fit your hard drive - 2.5" or
3.5". One such kit to look at:
http://www.ebay.com/itm/3-5-External-HDD-Hard-Disk-Drive-Enclosure-IDE-USB-2-0-Black-nice-/180745093613?pt=PCC_Drives_Storage_Internal&hash=item2a153f41ed

Cheers,
Dave M

==============================================================================
TOPIC: broke my own circuit - 4017 decade/Johnson counter
http://groups.google.com/group/sci.electronics.repair/t/33e2c80674da2af0?hl=en
==============================================================================

== 1 of 3 ==
Date: Wed, Oct 26 2011 7:46 am
From: DewDude

so im building a simple light chaser circuit out of a 4017 counter and
555 timer. the 555 timer circuit works. my problem is with thr 4017.

according to several schematics ive seen...and behavior in electronics
workbench/multisim, connecting the reset to output q4 causes the chip
to reset when q4 fires.

real-life behavior i different. if reset is connected to anything
except just ground, all it'll do is blink the first led.

any suggestions?

== 2 of 3 ==
Date: Wed, Oct 26 2011 12:39 pm
From: "Ian Field"

"DewDude" <dewdude@gmail.com> wrote in message
news:da4cb5a9-8d74-4143-b3ee-68d91454a243@q35g2000prh.googlegroups.com...
> so im building a simple light chaser circuit out of a 4017 counter and
> 555 timer. the 555 timer circuit works. my problem is with thr 4017.
>
> according to several schematics ive seen...and behavior in electronics
> workbench/multisim, connecting the reset to output q4 causes the chip
> to reset when q4 fires.
>
> real-life behavior i different. if reset is connected to anything
> except just ground, all it'll do is blink the first led.
>
> any suggestions?
>

You're resetting from the wrong end of the counter.

== 3 of 3 ==
Date: Wed, Oct 26 2011 1:12 pm
From: DewDude

On Oct 26, 3:39 pm, "Ian Field" <gangprobing.al...@ntlworld.com>
wrote:
> "DewDude" <dewd...@gmail.com> wrote in message
>
> news:da4cb5a9-8d74-4143-b3ee-68d91454a243@q35g2000prh.googlegroups.com...
>
> > so im building a simple light chaser circuit out of a 4017 counter and
> > 555 timer. the 555 timer circuit works. my problem is with thr 4017.
>
> > according to several schematics ive seen...and behavior in electronics
> > workbench/multisim, connecting the reset to output q4 causes the chip
> > to reset when q4 fires.
>
> > real-life behavior i different. if reset is connected to anything
> > except just ground, all it'll do is blink the first led.
>
> > any suggestions?
>
> You're resetting from the wrong end of the counter.

i dont see how. the counter will start with output q0....it
automatically cycles back to q0 after firing q9, the reset is supposed
to allow me to recycle back to q0 after firing a specific number of
leds.

explain your reasoning or stfu.

==============================================================================
TOPIC: home-brew Freon TF substitutes?
http://groups.google.com/group/sci.electronics.repair/t/f66a71610e41b61d?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Oct 26 2011 8:59 am
From: Jim Yanik

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in
news:H4Jpq.2929$M61.1622@newsfe09.ams2:

>
>
> "Jeff Layman" <JMLayman@invalid.invalid> wrote in message
> news:j83vnf$cjh$2@news.albasani.net...
>> On 24/10/2011 13:33, Nomen Nescio wrote:
>>> I last saw this in the mid 1990s. I knew a warehouse that still
>>> had some drums hidden away...
>>> Bloody best cleaner ever. Although some liked Genklene,
>>> now also banned.
>>> There are some commercial spray cleaners that claim to be
>>> almost as good. I would like something in bulk for dipping
>>> computer boards. Isopropyl alchohol is suggested by some,
>>> but has 9% water usually.
>>
>> Not sure where you are, but isopropyl alcohol is usually available
>> 99.9% pure, with a negligible water content.
>>
>> --
>>
>> Jeff
>
> I'd go along with that. The stuff specified as 'electronics grade' is
> typically at least 99.7% to get that rating
>
> Arfa
>
>

the IPA commonly available at drug stores is usually 90-91%,I believe,at
least in the US.

--
Jim Yanik
jyanik
at
localnet
dot com

==============================================================================
TOPIC: Peavey Valve King 212
http://groups.google.com/group/sci.electronics.repair/t/ec305ab9075c184c?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Oct 26 2011 9:25 am
From: Cydrome Leader

Cydrome Leader <presence@mungepanix.com> wrote:
> N_Cook <diverse@tcp.co.uk> wrote:
>> You would think that a 10W resistor marked on the schematic as a safety
>> device would mean that any wiring would be loomed away from it, not laying
>> along its length. Another safety issue with these amps, I was trying to see
>> where the chunky HT wire to the output amp was, but nothing obvious. It is
>> in the grey ribbon umbilical , >500V rating on that stuff? I doubt it. 6
>> months old , no warning signs of crap solder used, no PbF / RoHS /N or even
>> the CE mark for this , for export, 240V structured amp, just a wheelie bin
>> with an X over it.
>
> speaking of stupid symbols, what's the circle with an arrow possibly
> indicating some sort of rotation and a number "10" inside mean?

It's not a plastic type designator, I've seen it stamped on metal stuff
too.

==============================================================================
TOPIC: issue with electret condenser mic
http://groups.google.com/group/sci.electronics.repair/t/0f83e591aedae6bd?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Oct 26 2011 11:19 am
From: madscijr

Anyone?

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