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From: N_Cook on 7 Jul 2010 09:46
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


From: N_Cook on 7 Jul 2010 11:58
Meat Plow <mhywatt(a)yahoo.com> wrote in message
news:3supog.95r.19.30(a)news.alt.net...
> On Wed, 7 Jul 2010 14:46:36 +0100, "N_Cook" <diverse(a)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


From: nesesu on 7 Jul 2010 12:14
On Jul 7, 6:46 am, "N_Cook" <dive...(a)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.
From: N_Cook on 7 Jul 2010 12:24
nesesu <neil_sutcliffe(a)telus.net> wrote in message
news:b45df15a-4774-4c5d-a9c6-f908d334bd69(a)x1g2000prc.googlegroups.com...
On Jul 7, 6:46 am, "N_Cook" <dive...(a)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.

&&&&&&&

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


From: hr(bob) hofmann on 7 Jul 2010 15:52
On Jul 7, 8:46 am, "N_Cook" <dive...(a)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??
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