sci.electronics.repair - 25 new messages in 11 topics - digest

sci.electronics.repair
http://groups.google.com/group/sci.electronics.repair?hl=en

sci.electronics.repair@googlegroups.com

Today's topics:

==============================================================================
TOPIC: Rectifier wiring
http://groups.google.com/group/sci.electronics.repair/t/b087d99e9ce594b1?hl=en
==============================================================================

== 1 of 1 ==
Date: Tues, Jul 6 2010 10:50 pm
From: Winston

On 7/6/2010 10:26 AM, William Sommerwerck wrote:

(...)

> "Giving away" inventions is not necessarily a good thing. The patent system
> actually encourages invention by increasing the likelihood an inventor will
> profit from his ideas.

I'm sorry to inform you that you are in violation of
my rights to those thoughts.

My lawyer discovered that any practitioner in the
field *could* have easily originated those thoughts
before you did; they are insufficiently
novel.

Additionally, with further work, I believe
we will be able to uncover historical instances
of each of those thoughts occurring as 'prior art'.

You are to cease expression of those thoughts or any
thought that could be considered derivative of them.

Either of those thoughts are now available for license
from me for a single - use fee of US $5.00.

See how this really works? :)

--Winston

==============================================================================
TOPIC: Orange Rocker 30, combo, 2006
http://groups.google.com/group/sci.electronics.repair/t/fdf96ce609e107d9?hl=en
==============================================================================

== 1 of 2 ==
Date: Wed, Jul 7 2010 2:00 am
From: "Gareth Magennis"

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:89i3piFheoU1@mid.individual.net...
>
> "Gareth Magennis"
>> >
>>>>> The ones that were originally well made are now so old they have
>>>>> strange faults most techs have never seen before - while the ones
>>>>> made more recently have designed in faults never seen before by
>>>>> anyone.
>>>>>
>>>>> A few examples.
>>>>>
>>>>> 1. Recent Marshall combo amps with fibreglass PCBs that become LEAKY
>>>>> when hot - output valve bias goes crazy and even the phase splitter
>>>>> stage goes way out of DC balance in normal operation because of
>>>>> leakage
>>>>> from anode tracks to grid tracks. There is simply no fix for this
>>>>> problem.
>>>>
>>>>
>>>> Care to give me a model for that behaviour ?
>>>
>>>
>>> ** Yep - the JCM2000: TSL100 combo series.
>>>
>>> Easy to find many stories about the same problem on usenet and web
>>> forums.
>>>
>>>
>>
>> Yes, Marshal TSL 100. Sigh. I have had two of these with faulty
>> PCB's. They do indeed leak, and destroy the output tubes, as the bias
>> goes totally crazy.
>> I spent hours on the first one trying to establish what the fuck was
>> going
>> on, as it made no sense whatsoever.
>>
>>
>> Eventually I phoned Marshall. They know about this problem and are
>> unable
>> to fix it. You need to replace the PCB with an upgraded design.
>
>
> ** Hope the are willing to supply that for free ??
>
> Whole PCBs going leaky is hardly an example of "normal wear and tear".
>
>
>
> .... Phil
>
>
>

Er, no they ae not.

Gareth.

== 2 of 2 ==
Date: Wed, Jul 7 2010 8:19 am
From: Jeffrey D Angus

Gareth Magennis wrote:
> "Phil Allison" <phil_a@tpg.com.au> wrote in message
>> Whole PCBs going leaky is hardly an example of "normal wear and tear".
>
> Er, no they are not.
>

Tube sockets and PCBs have always been a problem.

The trick is to bite the bullet and mount the high power
tubes on the metal chassis and hand wire them to the
rest of the low power stuff on the PCB.

Jeff

--
"Egotism is the anesthetic that dulls the pain of stupidity."
Frank Leahy, Head coach, Notre Dame 1941-1954

http://www.stay-connect.com

==============================================================================
TOPIC: Just occasionally, it all works out ... :-)
http://groups.google.com/group/sci.electronics.repair/t/8acb2e5bc4fbe49f?hl=en
==============================================================================

== 1 of 7 ==
Date: Wed, Jul 7 2010 5:38 am
From: Meat Plow

On Wed, 07 Jul 2010 10:03:28 +1000, Franc Zabkar
<fzabkar@iinternode.on.net>wrote:

>On Tue, 6 Jul 2010 13:21:03 +0000 (UTC), Meat Plow <mhywatt@yahoo.com>
>put finger to keyboard and composed:
>
>>I once found a live rodent inside an old RCA radio/turntable console.
>
>He supplies the motive force for the turntable. Kinda like the
>Flintstones ...
>
>- Franc Zabkar

Damn, no wonder the TT styoped working after he escaped. I could never
figure that one out. Time to go to Pets-R-Us to look for a suitable
replacement. Might even check into a hamster as they live longer.

== 2 of 7 ==
Date: Wed, Jul 7 2010 5:43 am
From: klem kedidelhopper

On Jul 7, 8:38 am, Meat Plow <mhyw...@yahoo.com> wrote:
> On Wed, 07 Jul 2010 10:03:28 +1000, Franc Zabkar
> <fzab...@iinternode.on.net>wrote:
>
> >On Tue, 6 Jul 2010 13:21:03 +0000 (UTC), Meat Plow <mhyw...@yahoo.com>
> >put finger to keyboard and composed:
>
> >>I once found a live rodent inside an old RCA radio/turntable console.
>
> >He supplies the motive force for the turntable. Kinda like the
> >Flintstones ...
>
> >- Franc Zabkar
>
> Damn, no wonder the TT styoped working after he escaped. I could never
> figure that one out. Time to go to Pets-R-Us to look for a suitable
> replacement. Might even check into a hamster as they live longer.

Well at least you can still get spare parts for it.....

== 3 of 7 ==
Date: Wed, Jul 7 2010 5:42 am
From: "William Sommerwerck"

>> I once found a live rodent inside an old RCA
>> radio/turntable console.

> I've seen rodents elected to piblic office.

Ho-ars, too (as Gus would say).

== 4 of 7 ==
Date: Wed, Jul 7 2010 5:43 am
From: Meat Plow

On Tue, 06 Jul 2010 17:51:07 +0100, Ron
<ron@lunevalleyaudio.com>wrote:

>>>> I once found a live rodent inside an old RCA radio/turntable console.
>>>
>>> On more than on occasion I found dead and desicated mice inside
>>> microwave ovens with no apparent means of entry (or escape) I can only
>>> assume they were manufactured in.
>>>
>>> Ron(UK)- Hide quoted text -
>>>
>>> - Show quoted text -
>>
>> Inside the overall case, or actually inside the "oven"?
>
>In the cabinet, among the high voltages. It was quite common to find
>assorted dead insects in there, often ones not native to the UK.
>
>Ron

That's very odd. I've worked on a few Gold Star and Tatung micros when
I worked for a warranty center handling traffic from KMart and the
likes but don't recall seeing dead rodents/insects inside the back
especially on defective units right off the shelf. Units that had been
used and subesquently failed under warranty not that's a whole
different story. The main culprit in this case was the cockroach.

== 5 of 7 ==
Date: Wed, Jul 7 2010 6:03 am
From: bz

b <reverend_rogers@yahoo.com> wrote in
news:673c9f76-2105-4cb0-9c42-33d4e5be34cc@z10g2000yqb.googlegroups.com:

....
> I had this exact thing earlier this year! I was working on an AIWA
> system which would not read discs. was about to toss it aside when I
> noticed some dirt near the laser . After carefully removing the lens
> there was some kind of dead insect blocking the beam path - removed,
> cleaned up, reassembled and worked fine!
> why it chose precisely the most precision-made heart of the machine to
> live in is beyond me...

More precisely, 'why it chose that spot to die in ... ' :)

Perhaps it was exploring and the owner tried to play something, and it got
zapped by the 'death ray' from the laser.

> -B

== 6 of 7 ==
Date: Wed, Jul 7 2010 1:56 pm
From: "Dave"

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:EJDYn.71351$wi5.62269@hurricane...
> Been a right PITA day. One of those where everything you pick up is either
> not worth repairing, or seems to get worse if you as much as bring a
> screwdriver anywhere near it. And so it was with sinking heart that I put
> the Technics SL-PG480 CD player on the bench. "Not playing discs" said the
> ticket, and when I reached for a screwdriver, I needn't have bothered -
> the owner had already kindly removed all the case screws, to save me the
> trouble ... I probably should have just sighed at this point, and sent it
> back where it came from, but I've always liked these, so I thought I would
> just give it 5 minutes. Everything basically did what it should, except
> focus search didn't take place. That's an unusual problem on one of these,
> so I thought I would just whip the deck out first and have a look at the
> connectors, as someone had clearly been in there before me. There was
> nothing obviously wrong, so I thought I would just check the continuity to
> the laser focus coils whilst I could easily get at the connections. With
> an analogue meter on a low ohms range, I checked the coils. The tracking
> ones were fine, and the lens deflected left or right, but the focus ones
> read open, with no lens movement.
>
> The deck fitted to these is a Philips CDM12.1 and the lens carrier and
> coils are clearly visible and accessible on the top of the laser, so I had
> a close look with my powerful headband magnifier. You could clearly see
> that one of the superflexible tails that connect from the fixed pins that
> come up from the laser flexiprint to the focus and tracking coils on the
> lens carrier, was laying detached by the side of its pin. It didn't look
> broken - just never soldered or soldered properly in the first place.
> Pointy tweezers, a fine tipped iron, and some fine gauge solder, soon put
> that right, and the lens then deflected normally when the meter was
> applied again. All worked nicely, as these always do, when it was
> reassembled.
>
> Makes a change to get a decent result like that, and just goes to show
> that you shouldn't just get jaded with all the crap passing across your
> bench, and just not bother even attempting a repair on the basis that
> spares ain't gonna be available anyway ... d;~}
>
> Arfa

Isn't it *nice* when you get something like this to keep you going. Wife's
monitor went dark the other day, and since I'm the official fixer in the
house, she gave it to me. No power to the LCD screen. Found two
electrolytic caps shorted and the surface mount fuse on that board blown.
They were obviously filter caps, intended to cut down on ripple, and since I
couldn't get exact replacement parts I put in something physically and
electronically larger for the job. Replaced the fuse, and she is back up
and running. Funny thing is, they fit the physical space dedicated to the
job of filter caps better than the ones that were originally in there. Not
the slightest bit of difficulty pulling the others out and putting them in.
And if *they* overheat, there's something serious going on. I got an easy
fix, and wife is happy again. What else could you ask for?

Take it easy...

Dave

== 7 of 7 ==
Date: Wed, Jul 7 2010 5:22 pm
From: "Arfa Daily"

"Dave" <db5151@hotmail.com> wrote in message
news:xPGdnZRMavGSd6nRnZ2dnUVZ_gKdnZ2d@posted.internetamerica...
>
> "Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
> news:EJDYn.71351$wi5.62269@hurricane...
>> Been a right PITA day. One of those where everything you pick up is
>> either not worth repairing, or seems to get worse if you as much as bring
>> a screwdriver anywhere near it. And so it was with sinking heart that I
>> put the Technics SL-PG480 CD player on the bench. "Not playing discs"
>> said the ticket, and when I reached for a screwdriver, I needn't have
>> bothered - the owner had already kindly removed all the case screws, to
>> save me the trouble ... I probably should have just sighed at this
>> point, and sent it back where it came from, but I've always liked these,
>> so I thought I would just give it 5 minutes. Everything basically did
>> what it should, except focus search didn't take place. That's an unusual
>> problem on one of these, so I thought I would just whip the deck out
>> first and have a look at the connectors, as someone had clearly been in
>> there before me. There was nothing obviously wrong, so I thought I would
>> just check the continuity to the laser focus coils whilst I could easily
>> get at the connections. With an analogue meter on a low ohms range, I
>> checked the coils. The tracking ones were fine, and the lens deflected
>> left or right, but the focus ones read open, with no lens movement.
>>
>> The deck fitted to these is a Philips CDM12.1 and the lens carrier and
>> coils are clearly visible and accessible on the top of the laser, so I
>> had a close look with my powerful headband magnifier. You could clearly
>> see that one of the superflexible tails that connect from the fixed pins
>> that come up from the laser flexiprint to the focus and tracking coils on
>> the lens carrier, was laying detached by the side of its pin. It didn't
>> look broken - just never soldered or soldered properly in the first
>> place. Pointy tweezers, a fine tipped iron, and some fine gauge solder,
>> soon put that right, and the lens then deflected normally when the meter
>> was applied again. All worked nicely, as these always do, when it was
>> reassembled.
>>
>> Makes a change to get a decent result like that, and just goes to show
>> that you shouldn't just get jaded with all the crap passing across your
>> bench, and just not bother even attempting a repair on the basis that
>> spares ain't gonna be available anyway ... d;~}
>>
>> Arfa
>
> Isn't it *nice* when you get something like this to keep you going.
> Wife's monitor went dark the other day, and since I'm the official fixer
> in the house, she gave it to me. No power to the LCD screen. Found two
> electrolytic caps shorted and the surface mount fuse on that board blown.
> They were obviously filter caps, intended to cut down on ripple, and since
> I couldn't get exact replacement parts I put in something physically and
> electronically larger for the job. Replaced the fuse, and she is back up
> and running. Funny thing is, they fit the physical space dedicated to the
> job of filter caps better than the ones that were originally in there.
> Not the slightest bit of difficulty pulling the others out and putting
> them in. And if *they* overheat, there's something serious going on. I
> got an easy fix, and wife is happy again. What else could you ask for?
>
> Take it easy...
>
> Dave
>

Indeed Dave, and funnily enough, since that one "good 'un" at the start of
the week, I have had a really good run of repairs. Pretty much all stuff
with genuine problems, that were for the most part fixable with in-stock
parts, and parts actually available and reasonably priced, for the others.
Just one (and a half ! ) causing me problems at the moment ...

Arfa

==============================================================================
TOPIC: Polaroid TLX-04011C vertical stripe
http://groups.google.com/group/sci.electronics.repair/t/4c8b4302f2fee97b?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Jul 7 2010 5:38 am
From: klem kedidelhopper

On Jul 6, 2:28 pm, PlainBil...@yahoo.com wrote:
> On Tue, 6 Jul 2010 07:12:43 -0700 (PDT), klem kedidelhopper
>
> <captainvideo462...@gmail.com> wrote:
> >This set has a dim vertical bar about 4 inches wide just to the right
> >of center screen. There is a normal full color picture otherwise but
> >this "bar" is a bit dimmer than the rest of the screen, and so its
> >noticible. The strange thing is though depending upon the scene
> >sometimes you don't notice it at all and at other times it seems quite
> >prominent. At times you can notice smears of red going through this
> >area as well. The customer says he did a search on this thing and
> >seems to think it needs a "capacitor". But then sometimes they tell me
> >its the switch when it won't turn on too. I looked but found nothing
> >that really seems to pertain to this problem exectly.
> >Does anyone have any experience with this problem on this set? Thanks,
> >Lenny
>
> Is this a sharply deliniated bar, indicating a problem with columns of
> pixels, or do the edges gradually merge into the 'good' area.
> A sharp edged column would indicate a problem either with a column
> driver in the LCD panel itself (not repairable), or the t-con board
> (usually replaceable).
>
> A dimmer column with no sharp edges could indicate a backlight
> problem.
>
> As far as the customer's suggestion, while it is unlikely, this
> wouldn't be the first time some very strange symptoms resulted from a
> marginal capacitor.
>
> PlainBill

The edges are sharply defined however the "column" is slightly
somewhat dimmer than the rest of the picture. That's what makes it
noticeable I guess. How do you rule out /in a t con board? I did try
cleaning the cable but it made no difference.Thanks, Lenny

==============================================================================
TOPIC: Electric fence operation problem
http://groups.google.com/group/sci.electronics.repair/t/eef28366a8aa3bbf?hl=en
==============================================================================

== 1 of 8 ==
Date: Wed, Jul 7 2010 6:46 am
From: "N_Cook"

2 stage derivation of (should be) 1800V pulses.
Fence had failure in the first stage probably due to intermittant corroded
battery supply contact.
Anyway the 15A 60V 8N06 powerFET blew along with an associated double diode
BAV23.
Replaced both and works to some extent. This FET has plenty of drive 5V of
pulses of repeat 3uS for the gate and about 3V ringing swing on the output
to the first step up transformer. I assume that is as to be expected, never
having the chance to see hot-side SMPS drive scope traces.
But rectified output only climbs to about 1V of DC before the final stage
(unreadable marking) thyristor discharges that supply into the second step
up transformer, but of course not even enough to get a glow on a 110V neon.
Doubling the C setting the 3uS pulses, to give longer repeat rate and that
intermediary voltage rises to about 3V but still not enough for any proper
final output. Adding more C and DC is then much less than 3V.
What would people expect the intermediary DC to be? obviously higher than
12V battery supply
Next stage would be disconnect the thyristor if that should be working but
leaky and draining the intermediary DC but any other ideas? Would explain
why the printing is very indistinct I suppose.
DC ohms of the airgap type transformers are
intermediary 0.1R//10.6R
HV 0.3R//29R which seem reasonable, ie not major shorted turns if any

== 2 of 8 ==
Date: Wed, Jul 7 2010 7:50 am
From: Meat Plow

On Wed, 7 Jul 2010 14:46:36 +0100, "N_Cook" <diverse@tcp.co.uk>wrote:

>2 stage derivation of (should be) 1800V pulses.
>Fence had failure in the first stage probably due to intermittant corroded
>battery supply contact.
>Anyway the 15A 60V 8N06 powerFET blew along with an associated double diode
>BAV23.
>Replaced both and works to some extent. This FET has plenty of drive 5V of
>pulses of repeat 3uS for the gate and about 3V ringing swing on the output
>to the first step up transformer. I assume that is as to be expected, never
>having the chance to see hot-side SMPS drive scope traces.
>But rectified output only climbs to about 1V of DC before the final stage
>(unreadable marking) thyristor discharges that supply into the second step
>up transformer, but of course not even enough to get a glow on a 110V neon.
>Doubling the C setting the 3uS pulses, to give longer repeat rate and that
>intermediary voltage rises to about 3V but still not enough for any proper
>final output. Adding more C and DC is then much less than 3V.
>What would people expect the intermediary DC to be? obviously higher than
>12V battery supply
>Next stage would be disconnect the thyristor if that should be working but
>leaky and draining the intermediary DC but any other ideas? Would explain
>why the printing is very indistinct I suppose.
>DC ohms of the airgap type transformers are
>intermediary 0.1R//10.6R
>HV 0.3R//29R which seem reasonable, ie not major shorted turns if any
>

I would expect the output to be at fault when you take into
consideration all the short circuits electric fencing can encounter.

== 3 of 8 ==
Date: Wed, Jul 7 2010 8:58 am
From: "N_Cook"

Meat Plow <mhywatt@yahoo.com> wrote in message
news:3supog.95r.19.30@news.alt.net...
> On Wed, 7 Jul 2010 14:46:36 +0100, "N_Cook" <diverse@tcp.co.uk>wrote:
>
> >2 stage derivation of (should be) 1800V pulses.
> >Fence had failure in the first stage probably due to intermittant
corroded
> >battery supply contact.
> >Anyway the 15A 60V 8N06 powerFET blew along with an associated double
diode
> >BAV23.
> >Replaced both and works to some extent. This FET has plenty of drive 5V
of
> >pulses of repeat 3uS for the gate and about 3V ringing swing on the
output
> >to the first step up transformer. I assume that is as to be expected,
never
> >having the chance to see hot-side SMPS drive scope traces.
> >But rectified output only climbs to about 1V of DC before the final stage
> >(unreadable marking) thyristor discharges that supply into the second
step
> >up transformer, but of course not even enough to get a glow on a 110V
neon.
> >Doubling the C setting the 3uS pulses, to give longer repeat rate and
that
> >intermediary voltage rises to about 3V but still not enough for any
proper
> >final output. Adding more C and DC is then much less than 3V.
> >What would people expect the intermediary DC to be? obviously higher than
> >12V battery supply
> >Next stage would be disconnect the thyristor if that should be working
but
> >leaky and draining the intermediary DC but any other ideas? Would explain
> >why the printing is very indistinct I suppose.
> >DC ohms of the airgap type transformers are
> >intermediary 0.1R//10.6R
> >HV 0.3R//29R which seem reasonable, ie not major shorted turns if any
> >
>
> I would expect the output to be at fault when you take into
> consideration all the short circuits electric fencing can encounter.

I've disconnected the HV section and no difference. The o/p of the
intermediate is 4V pk-pk pulses with designed 3uS osc i/p. Barely enough to
exceed the bank of 6 seriesed rectifier diodes . Inductances of the
intermediate Tr are 0.1mH and 84mH . i'm wondering if there is shorted
turns, will try and find some SMPS to try in reverse.
The output Tr is E-I iron cored not HF on closer looking

== 4 of 8 ==
Date: Wed, Jul 7 2010 9:14 am
From: nesesu

On Jul 7, 6:46 am, "N_Cook" <dive...@tcp.co.uk> wrote:
> 2 stage derivation of (should be) 1800V pulses.
> Fence had failure in the first stage probably due to intermittant corroded
> battery supply contact.
> Anyway the 15A 60V 8N06 powerFET blew along with an associated double diode
> BAV23.
> Replaced both and works to some extent. This FET has plenty of drive 5V of
> pulses of repeat 3uS for the gate and about 3V ringing swing on the output
> to the first step up transformer. I assume that is as to be expected, never
> having the chance to see hot-side SMPS drive scope traces.
> But rectified output only climbs to about 1V of DC before the final stage
> (unreadable marking) thyristor discharges that supply into the second step
> up transformer, but of course not even enough to get a glow on a 110V neon.
> Doubling the C setting the 3uS pulses, to give longer repeat rate and that
> intermediary voltage rises to about 3V but still not enough for any proper
> final output. Adding more C and DC is then much less than 3V.
> What would people expect the intermediary DC to be? obviously higher than
> 12V battery supply
> Next stage would be disconnect the thyristor if that should be working but
> leaky and draining the intermediary DC but any other ideas? Would explain
> why the printing is very indistinct I suppose.
> DC ohms of the airgap type transformers are
> intermediary 0.1R//10.6R
> HV 0.3R//29R which seem reasonable, ie not major shorted turns if any

Sounds like the unit may have been hit by a lightning surge. I have
seen a few and usually all the electronic parts are blown as well at
the transformer winding insulation punctured.
To your question of intermediate voltage, I would suspect something in
the 50-100V range. I imagine that there is a storage cap since your
description sounds like a C-D circuit, so one would expect the
intermediate voltage to be around 60% of the cap voltage rating, if it
is an electrolytic.
Neil S.

== 5 of 8 ==
Date: Wed, Jul 7 2010 9:24 am
From: "N_Cook"

nesesu <neil_sutcliffe@telus.net> wrote in message
news:b45df15a-4774-4c5d-a9c6-f908d334bd69@x1g2000prc.googlegroups.com...
On Jul 7, 6:46 am, "N_Cook" <dive...@tcp.co.uk> wrote:
> 2 stage derivation of (should be) 1800V pulses.
> Fence had failure in the first stage probably due to intermittant corroded
> battery supply contact.
> Anyway the 15A 60V 8N06 powerFET blew along with an associated double
diode
> BAV23.
> Replaced both and works to some extent. This FET has plenty of drive 5V of
> pulses of repeat 3uS for the gate and about 3V ringing swing on the output
> to the first step up transformer. I assume that is as to be expected,
never
> having the chance to see hot-side SMPS drive scope traces.
> But rectified output only climbs to about 1V of DC before the final stage
> (unreadable marking) thyristor discharges that supply into the second step
> up transformer, but of course not even enough to get a glow on a 110V
neon.
> Doubling the C setting the 3uS pulses, to give longer repeat rate and that
> intermediary voltage rises to about 3V but still not enough for any proper
> final output. Adding more C and DC is then much less than 3V.
> What would people expect the intermediary DC to be? obviously higher than
> 12V battery supply
> Next stage would be disconnect the thyristor if that should be working but
> leaky and draining the intermediary DC but any other ideas? Would explain
> why the printing is very indistinct I suppose.
> DC ohms of the airgap type transformers are
> intermediary 0.1R//10.6R
> HV 0.3R//29R which seem reasonable, ie not major shorted turns if any

&&&&&&&

I'd not thought of that route, will desolder the C, script on the wrong
side. I'd expect the dual monostable IC to be knocked out with lightning

== 6 of 8 ==
Date: Wed, Jul 7 2010 10:24 am
From: Meat Plow

On Wed, 7 Jul 2010 16:58:36 +0100, "N_Cook" <diverse@tcp.co.uk>wrote:

>Meat Plow <mhywatt@yahoo.com> wrote in message
>news:3supog.95r.19.30@news.alt.net...
>> On Wed, 7 Jul 2010 14:46:36 +0100, "N_Cook" <diverse@tcp.co.uk>wrote:
>>
>> >2 stage derivation of (should be) 1800V pulses.
>> >Fence had failure in the first stage probably due to intermittant
>corroded
>> >battery supply contact.
>> >Anyway the 15A 60V 8N06 powerFET blew along with an associated double
>diode
>> >BAV23.
>> >Replaced both and works to some extent. This FET has plenty of drive 5V
>of
>> >pulses of repeat 3uS for the gate and about 3V ringing swing on the
>output
>> >to the first step up transformer. I assume that is as to be expected,
>never
>> >having the chance to see hot-side SMPS drive scope traces.
>> >But rectified output only climbs to about 1V of DC before the final stage
>> >(unreadable marking) thyristor discharges that supply into the second
>step
>> >up transformer, but of course not even enough to get a glow on a 110V
>neon.
>> >Doubling the C setting the 3uS pulses, to give longer repeat rate and
>that
>> >intermediary voltage rises to about 3V but still not enough for any
>proper
>> >final output. Adding more C and DC is then much less than 3V.
>> >What would people expect the intermediary DC to be? obviously higher than
>> >12V battery supply
>> >Next stage would be disconnect the thyristor if that should be working
>but
>> >leaky and draining the intermediary DC but any other ideas? Would explain
>> >why the printing is very indistinct I suppose.
>> >DC ohms of the airgap type transformers are
>> >intermediary 0.1R//10.6R
>> >HV 0.3R//29R which seem reasonable, ie not major shorted turns if any
>> >
>>
>> I would expect the output to be at fault when you take into
>> consideration all the short circuits electric fencing can encounter.
>
>I've disconnected the HV section and no difference. The o/p of the
>intermediate is 4V pk-pk pulses with designed 3uS osc i/p. Barely enough to
>exceed the bank of 6 seriesed rectifier diodes . Inductances of the
>intermediate Tr are 0.1mH and 84mH . i'm wondering if there is shorted
>turns, will try and find some SMPS to try in reverse.
>The output Tr is E-I iron cored not HF on closer looking
>

Would be nice to know the normal pulses of the driver circuit. It is
possible a shorted device in the output could damage the driven stage.

== 7 of 8 ==
Date: Wed, Jul 7 2010 12:52 pm
From: "hr(bob) hofmann@att.net"

On Jul 7, 8:46 am, "N_Cook" <dive...@tcp.co.uk> wrote:
> 2 stage derivation of (should be) 1800V pulses.
> Fence had failure in the first stage probably due to intermittant corroded
> battery supply contact.
> Anyway the 15A 60V 8N06 powerFET blew along with an associated double diode
> BAV23.
> Replaced both and works to some extent. This FET has plenty of drive 5V of
> pulses of repeat 3uS for the gate and about 3V ringing swing on the output
> to the first step up transformer. I assume that is as to be expected, never
> having the chance to see hot-side SMPS drive scope traces.
> But rectified output only climbs to about 1V of DC before the final stage
> (unreadable marking) thyristor discharges that supply into the second step
> up transformer, but of course not even enough to get a glow on a 110V neon.
> Doubling the C setting the 3uS pulses, to give longer repeat rate and that
> intermediary voltage rises to about 3V but still not enough for any proper
> final output. Adding more C and DC is then much less than 3V.
> What would people expect the intermediary DC to be? obviously higher than
> 12V battery supply
> Next stage would be disconnect the thyristor if that should be working but
> leaky and draining the intermediary DC but any other ideas? Would explain
> why the printing is very indistinct I suppose.
> DC ohms of the airgap type transformers are
> intermediary 0.1R//10.6R
> HV 0.3R//29R which seem reasonable, ie not major shorted turns if any

No manufacturer information aailable??

== 8 of 8 ==
Date: Wed, Jul 7 2010 3:10 pm
From: Franc Zabkar

On Wed, 7 Jul 2010 14:46:36 +0100, "N_Cook" <diverse@tcp.co.uk> put
finger to keyboard and composed:

>What would people expect the intermediary DC to be? obviously higher than
>12V battery supply

B20 Dry Battery Energiser:
http://www.forcefield-uk.co.uk/b20.htm

If the above is your electric fence device, then the Stored Joules
rating of 0.2J should enable you to calculate the voltage across the
HV capacitor.

E = 1/2 x C x V^2

so V = sqrt (2 x 0.2 / C)

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

==============================================================================
TOPIC: Tag Heuer Watch wholesale <free shipping paypal payment> (http://
http://groups.google.com/group/sci.electronics.repair/t/0336445b78c90071?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Jul 7 2010 6:51 am
From: jersey-2009

Ebel Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Bape Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
bell&ross Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Breit Ling Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Burberry Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Cartier Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Chopard Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
d&g Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Givenchy Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
jacob&co Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Kappa Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Prada Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Tissot Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Titoni Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
U-BOAT Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Zenith Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
a.lange&sohne Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Audemars Piguet Watch wholesale <free shipping paypal payment>
(http://www.brandtrade99.com/)
baume&mercier Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Blancpain Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Breguet Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
BRM Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Bvlgari Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Chanel Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Concord Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Corum Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Dewitt Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Ferrari Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Franck Muller Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Girard Perregaux Watch <free shipping paypal payment> (http://
www.brandtrade99.com/)
Glashutte Watch <free shipping paypal payment> (http://
www.brandtrade99.com/)
Graham Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
GUCCI Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
GUESS Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Hamilton Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Hermes Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Hublot Watch wholesale <free shipping paypal payment>

http://www.brandtrade99.com/)
IWC Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Jaeger Le Coultre Watch wholesale <free shipping paypal payment>
(http://www.brandtrade99.com/)
Longines Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
LV Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Montblanc Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Movado Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Omega Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Oris Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Paket Philippe Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Panerai Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Parmigiani Fleurier Watch wholesale <free shipping paypal payment>
(http://www.brandtrade99.com/)
Piaget Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Porsche Design Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Rolex Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Romain Jerome Titanic-Dna Watch wholesale <free shipping paypal
payment>(http://www.brandtrade99.com/)
Tag Heuer Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Tudor Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
Vach.Constantine Watch wholesale <free shipping paypal payment>
(http://www.brandtrade99.com/)
Armani Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)
RADO Watch wholesale <free shipping paypal payment> (http://
www.brandtrade99.com/)

==============================================================================
TOPIC: Movado Watch wholesale <free shipping paypal payment> (http://
http://groups.google.com/group/sci.electronics.repair/t/139e67fbac1d4568?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Jul 7 2010 7:12 am
From: fashion t shirts seller

==============================================================================
TOPIC: MCZ300DB original Sony vs generic
http://groups.google.com/group/sci.electronics.repair/t/66b70653725bbc37?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Jul 7 2010 8:29 am
From: klem kedidelhopper

My distributor finally has these in stock. Both the OEM as well as the
generics. The Sony parts are 16.95 while the generics are 9.60 Has
anyone had any bad experiences using the generics in the D board
application repair? I've used a lot of them without incident. However
I have a set in which we replaced the chips with generics about 6
months ago. We also did the cap as well. The set was fine for awhile
but lately at times it will just not start up. The problem is very
intermittent though. I thought that I would try a new pair of chips
and see what happens.
Lenny.

==============================================================================
TOPIC: Don't look for job let jobs look for you
http://groups.google.com/group/sci.electronics.repair/t/3ccbf69a0213c081?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Jul 7 2010 9:08 am
From: "m2004a2005s@yahoo.com"

Don't look for job let jobs look for you
http://insuracelaw.blogspot.com/

==============================================================================
TOPIC: Discount Wholesale LRG Jeans <free shipping paypal payment>
http://groups.google.com/group/sci.electronics.repair/t/2a8fefeb21828740?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Jul 7 2010 10:31 pm
From: POLO TSHIRT

Cheap Wholesale jeans:
cheap EVISU jeans wholesale (free shipping http://www.jialiuonline.com/
)
cheap ED hardy jeans wholesale
cheap COOGI jeans wholesale (paypal payment)( http://www.jialiuonline.com/
)
cheap GINO GREEN GLOBAL jeans wholesale
cheap LACOSTE jeans wholesale
cheap G-STAR jeans wholesale
cheap KED ROBOT jeans wholesale (free shipping http://www.jialiuonline.com/
)
cheap RED MONKEY jeans wholesale
cheap ADIDAS jeans wholesale -
cheap BBC jeans wholesale (paypal payment)( http://www.jialiuonline.com/
)
cheap BOSS jeans wholesale
cheap LRG jeans wholesale (paypal payment)( http://www.jialiuonline.com/
)
cheap HELEN jeans wholesale
cheap JUICY jeans wholesale
cheap THE CROUN HOLDER jeans wholesale
cheap SMET jeans wholesale
cheap SEVEN jeans wholesale (paypal payment)( http://www.jialiuonline.com/
)
cheap TRUN NORTH FACE jeans wholesale
cheap children jeans wholesale
cheap ARMANI jeans wholesale (paypal payment)( http://www.jialiuonline.com/
)

Discount Wholesale Affliction Jeans <free shipping paypal payment>
Discount Wholesale AK Jeans
Discount Wholesale Armani Jeans
Discount Wholesale Artful Dodger Jeans
Discount Wholesale BAPE Jeans
Discount Wholesale BBC Jeans
Discount Wholesale Black Label Jeans
Discount Wholesale Cavalli Jeans <free shipping paypal payment>
Discount Wholesale Christian Audigier Jeans
Discount Wholesale Coogi Jeans
Discount Wholesale Crown Holder Jeans
Discount Wholesale D&G Jeans
Discount Wholesale Diesel Jeans
Discount Wholesale ECKO Jeans
Discount Wholesale ED Hardy Jeans
Discount Wholesale Evisu Jeans
Discount Wholesale G-STAR Jeans <free shipping paypal payment>
Discount Wholesale GUCCI Jeans
Discount Wholesale Iceberg Jeans
Discount Wholesale Kanji Jeans
Discount Wholesale Laguna Beach Jeans
Discount Wholesale Levi s Jeans
Discount Wholesale LRG Jeans <free shipping paypal payment>
Discount Wholesale LV Jeans
Discount Wholesale Prada Jeans
Discount Wholesale RMC Jeans
Discount Wholesale Roca Wear Jeans <free shipping paypal payment>
Discount Wholesale Rock&Republic Jeans

==============================================================================
TOPIC: Cheap wholesale PRADA goggle (paypal payment
http://groups.google.com/group/sci.electronics.repair/t/36f42e385aac5bbb?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Jul 7 2010 10:31 pm
From: POLO TSHIRT

asunglasses:
Cheap wholesale ADIDAS Sunglass (paypal payment

http://www.jialiuonline.com/)
Cheap wholesale ARMANI Sunglass
Cheap wholesale Burberry Sunglass

(http://www.jialiuonline.com/ free
shipping)
Cheap wholesale BVLGARL Sunglass
Cheap wholesale Cartier Sunglass (paypal payment

http://www.jialiuonline.com/)
Cheap wholesale CHANEL Sunglass
Cheap wholesale COACH Sunglass
Cheap wholesale D&G Sunglass (paypal payment

http://www.jialiuonline.com/)
Cheap wholesale DIESEL Sunglass
Cheap wholesale DIOR Sunglass
Cheap wholesale ED Hardy Sunglass

(http://www.jialiuonline.com/ free
shipping)
Cheap wholesale FENDI Sunglass
Cheap wholesale Ferragamo Sunglass (paypal payment

http://www.jialiuonline.com/)
Cheap wholesale GIVENCHY Sunglass
Cheap wholesale GUCCI Sunglass

(http://www.jialiuonline.com/ free shipping)
Cheap wholesale LV Sunglass
Cheap wholesale NIKE Sunglass (paypal payment

http://www.jialiuonline.com/)
Cheap wholesale Oakley Sunglass
Cheap wholesale POLICE Sunglass (paypal payment

http://www.jialiuonline.com/)
Cheap wholesale PRADA Sunglass
Cheap wholesale Ray.Ban Sunglass
Cheap wholesale ROBERTO CAVALLI Sunglass (paypal payment

http://www.jialiuonline.com/)
Cheap wholesale Salvatore Sunglass
Cheap wholesale VERSACE Sunglass
Cheap wholesale YSL Sunglass
goggle:
(paypal payment http://www.jialiuonline.com/)

(http://www.jialiuonline.com/ free
shipping)
Cheap wholesale Armani goggle
Cheap wholesale Catier goggle
Cheap wholesale Chanel goggle

(http://www.jialiuonline.com/ free shipping)
Cheap wholesale D&G goggle (paypal payment

http://www.jialiuonline.com/)
Cheap wholesale DIOR goggle
Cheap wholesale FENDI goggle
Cheap wholesale FERRE goggle

(http://www.jialiuonline.com/ free shipping)
Cheap wholesale FRED goggle
Cheap wholesale GUCCI goggle (paypal payment

http://www.jialiuonline.com/)
Cheap wholesale LV goggle
Cheap wholesale MONT BLANC goggle
Cheap wholesale NIKE goggle
Cheap wholesale Oakley goggle

(http://www.jialiuonline.com/ free shipping)
Cheap wholesale POLICE goggle
Cheap wholesale PRADA goggle (paypal payment

http://www.jialiuonline.com/)
Cheap wholesale PUMA goggle
Cheap wholesale RAY.BAN goggle
Cheap wholesale VERSACE goggle (paypal payment

http://www.jialiuonline.com/)

==============================================================================

You received this message because you are subscribed to the Google Groups "sci.electronics.repair"
group.

To post to this group, visit http://groups.google.com/group/sci.electronics.repair?hl=en

To unsubscribe from this group, send email to sci.electronics.repair+unsubscribe@googlegroups.com

To change the way you get mail from this group, visit:
http://groups.google.com/group/sci.electronics.repair/subscribe?hl=en

To report abuse, send email explaining the problem to abuse@googlegroups.com

==============================================================================
Google Groups: http://groups.google.com/?hl=en

Electronics

sci.electronics.repair - 25 new messages in 11 topics - digest

No Response to "sci.electronics.repair - 25 new messages in 11 topics - digest"

Post a Comment

Blog Roll

Blog Archive