sci.electronics.repair - 25 new messages in 5 topics - digest

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

sci.electronics.repair@googlegroups.com

Today's topics:

* t.v. volume remains static. - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/8fbadf0c35306061?hl=en
* Contactor coil: 50 Hz vs. 60 Hz - 16 messages, 10 authors
http://groups.google.com/group/sci.electronics.repair/t/0d1a06068779ce43?hl=en
* OT: Tek 465 - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/b9f473fde6856891?hl=en
* Tektronix 7603 - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/efb86f5dc14fc24b?hl=en
* How to resolder a cold solder connection? - 4 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/46868719284715b1?hl=en

==============================================================================
TOPIC: t.v. volume remains static.
http://groups.google.com/group/sci.electronics.repair/t/8fbadf0c35306061?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Aug 29 2011 1:18 am
From: "William Sommerwerck"

<delroy_dobbs1@yahoo.com> wrote in message
news:e5b4f6ac-86a4-47bc-9b31-6d7cadfa5568@a27g2000yqc.googlegroups.com...

> NB: There is no bridges across the IC pins.

1. The new chip is defective. --or--
2. This problem existed before you replaced the chip. --or--
3. You damaged something when you removed the old chip or soldered in the
new one. --or--
4. There really is a solder bridge across two of the IC pins (or elsewhere).

Always keep in mind what Sherlock Holmes said.

== 2 of 2 ==
Date: Mon, Aug 29 2011 6:26 am
From: Winston

William Sommerwerck wrote:
> <delroy_dobbs1@yahoo.com> wrote in message
> news:e5b4f6ac-86a4-47bc-9b31-6d7cadfa5568@a27g2000yqc.googlegroups.com...
>
>> NB: There is no bridges across the IC pins.
>
> 1. The new chip is defective. --or--
> 2. This problem existed before you replaced the chip. --or--
> 3. You damaged something when you removed the old chip or soldered in the
> new one. --or--
> 4. There really is a solder bridge across two of the IC pins (or elsewhere).
>
> Always keep in mind what Sherlock Holmes said.

Quite so.

"Madam, I need you to remain calm. Trust me, I'm a professional
and beneath this pillow lies the key to my release."

--Winston

==============================================================================
TOPIC: Contactor coil: 50 Hz vs. 60 Hz
http://groups.google.com/group/sci.electronics.repair/t/0d1a06068779ce43?hl=en
==============================================================================

== 1 of 16 ==
Date: Mon, Aug 29 2011 1:41 am
From: Rich Grise

DaveC wrote:

> I may be able to obtain a very small 2-pole 240 vac contactor I need rated
> for 50 Hz only.
>
> If I install it in N. America, what's the implication? Is the hold-in
> magnetism less than if it were 60 Hz? Just noisy?
>
> Please don't ask or suggest other sources. This is a very specific device
> and I've not been able to locate other than this.
>
Plug one into 60 Hz and find out what happens. It will probably work just
fine. The Mfr only rated it for 50 because they weren't expecting
international sales.

Are you allowed to tell us why it has to be such a narrow menu of choices?

Thanks,
Rich

== 2 of 16 ==
Date: Mon, Aug 29 2011 1:58 am
From: andrew@cucumber.demon.co.uk (Andrew Gabriel)

In article <0001HW.CA807E1401D86A41B01029BF@news.eternal-september.org>,
DaveC <invalid@invalid.net> writes:
> I may be able to obtain a very small 2-pole 240 vac contactor I need rated
> for 50 Hz only.
>
> If I install it in N. America, what's the implication? Is the hold-in
> magnetism less than if it were 60 Hz? Just noisy?

Yes, the hold-in force will be proportionally less. If the
coil impedance was due entirely to the inductance, it would
be 50/60ths of the force. However, part of the current limiting
is done by the coil resistance, and that won't change so the
reduction in hold-in force will actually be less than this.

The pull-in force before the magnetic core is closed also
depend on the impedance and resistance, but the impedance
will be lower, and thus the pull-in force will be reduced by
even less.

The pull-in force usually has to overcome a faily weak return
spring. The hold-in force has to overcome a stronger contact
pressure spring. Providing both these conditions are still met,
you should be OK. Ideally, you should check that you have a
reasonable working margin by testing the coil at lower
voltage. If you don't, then the contactor might fail to
close properly on minimum supply conditions which could cause
it to burn out.

I would not expect it to be more noisy if it closes properly.
Noise would be an indication that is isn't closing properly.

Of course, you void all waranties and certifications by
operating it outside of it's specified ratings. The
manufacturers advice should be sought, but unless you are
buying lots of them, they probably won't commit other than
to say it's at your own risk.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

== 3 of 16 ==
Date: Mon, Aug 29 2011 4:29 am
From: "petrus bitbyter"

"DaveC" <invalid@invalid.net> schreef in bericht
news:0001HW.CA807E1401D86A41B01029BF@news.eternal-september.org...
>I may be able to obtain a very small 2-pole 240 vac contactor I need rated
> for 50 Hz only.
>
> If I install it in N. America, what's the implication? Is the hold-in
> magnetism less than if it were 60 Hz? Just noisy?
>
> Please don't ask or suggest other sources. This is a very specific device
> and
> I've not been able to locate other than this.
>
> Thanks,
> Dave
>

As we have very limited information about this device and its usage, I can
only suggest two possible solutions:
- The easy one: Just try it out.
- Build a piece of electronics that converts your 60Hz to 50Hz.
Dimensions of that electronics depend on the required current.

petrsu bitbyter

== 4 of 16 ==
Date: Mon, Aug 29 2011 5:38 am
From: Spehro Pefhany

On Mon, 29 Aug 2011 08:58:55 +0000 (UTC), the renowned
andrew@cucumber.demon.co.uk (Andrew Gabriel) wrote:

>In article <0001HW.CA807E1401D86A41B01029BF@news.eternal-september.org>,
> DaveC <invalid@invalid.net> writes:
>> I may be able to obtain a very small 2-pole 240 vac contactor I need rated
>> for 50 Hz only.
>>
>> If I install it in N. America, what's the implication? Is the hold-in
>> magnetism less than if it were 60 Hz? Just noisy?
>
>Yes, the hold-in force will be proportionally less. If the
>coil impedance was due entirely to the inductance, it would
>be 50/60ths of the force. However, part of the current limiting
>is done by the coil resistance, and that won't change so the
>reduction in hold-in force will actually be less than this.
>
>The pull-in force before the magnetic core is closed also
>depend on the impedance and resistance, but the impedance
>will be lower, and thus the pull-in force will be reduced by
>even less.
>
>The pull-in force usually has to overcome a faily weak return
>spring. The hold-in force has to overcome a stronger contact
>pressure spring. Providing both these conditions are still met,
>you should be OK. Ideally, you should check that you have a
>reasonable working margin by testing the coil at lower
>voltage. If you don't, then the contactor might fail to
>close properly on minimum supply conditions which could cause
>it to burn out.

<snip>

A side effect of reduced holding force can be that it is more
sensitive to opening due to external vibration in the wrong axis (and
especially so when the input voltage is on the low side). That could
cause malfunction of whatever it's connected to and premature failure
of the contactor. This might not be so easy to test without a shaker
table etc., but it should be considered if the operating conditions
involve vibration (including vibration from another nearby contactor).

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

== 5 of 16 ==
Date: Mon, Aug 29 2011 7:03 am
From: John Fields

On Sun, 28 Aug 2011 23:21:56 -0700, DaveC <invalid@invalid.net> wrote:

---
Not knowing the specifics about the coil makes predicting what will
happen at 60Hz difficult.

However, assuming that the inductive reactance and resistance of the
coil will remain constant at 50 and 60Hz means that the impedance of
the coil at 60Hz will be 1.2 times (60Hz/50Hz) what it is at 50Hz.

Consequently, the current in the coil at 60Hz will be about 83% of
what it is at 50Hz.

If that turns out to be a problem, a higher drive voltage could be
used in order to increase the current, namely 1.2 times 240V; 288V.

That could easily be accomplished using a transformer to boost the
240V mains to 288V, like this: (View with a fixed pitch font.)

240AC>-----+--+
| |
oP||S
R||E
I||Co
| |
| +-----> \
| > 288AC TO COIL
240AC>-----+--------> /

The transformer would need a 240V primary, a 48V secondary, and a VA
rating greater than or equal to the contactor coil's rating.

If you go here:

http://www.signaltransformer.com/content/split-bobbin-with-isolation

and select the input as 115/230 and the output as 48, you'll wind up
with 5 transformers rated at from 6 to 400 VA, one of which would
surely work.

Also, many manufacturers make similar transformers, and Digi-Key and
Mouser stock quite a few.

--
JF

== 6 of 16 ==
Date: Mon, Aug 29 2011 7:28 am
From: NT

On Aug 29, 3:03 pm, John Fields <jfie...@austininstruments.com> wrote:
> On Sun, 28 Aug 2011 23:21:56 -0700, DaveC <inva...@invalid.net> wrote:
> >I may be able to obtain a very small 2-pole 240 vac contactor I need rated
> >for 50 Hz only.
>
> >If I install it in N. America, what's the implication? Is the hold-in
> >magnetism less than if it were 60 Hz? Just noisy?
>
> >Please don't ask or suggest other sources. This is a very specific device and
> >I've not been able to locate other than this.
>

> Not knowing the specifics about the coil makes predicting what will
> happen at 60Hz difficult.
>
> However, assuming that the inductive reactance and resistance of the
> coil will remain constant at 50 and 60Hz means that the impedance of
> the coil at 60Hz will be 1.2 times (60Hz/50Hz) what it is at 50Hz.

no, only the L component of the impedance will be 1.2 times as high.

> Consequently, the current in the coil at 60Hz will be about 83% of
> what it is at 50Hz.
>
> If that turns out to be a problem, a higher drive voltage could be
> used in order to increase the current, namely 1.2 times 240V; 288V.
>
> That could easily be accomplished using a transformer to boost the
> 240V mains to 288V, like this: (View with a fixed pitch font.)
>
> 240AC>-----+--+
> | |
> oP||S
> R||E
> I||Co
> | |
> | +-----> \
> | > 288AC TO COIL
> 240AC>-----+--------> /
>
> The transformer would need a 240V primary, a 48V secondary, and a VA
> rating greater than or equal to the contactor coil's rating.

these are the kind of 'solutions' that happen when people dont put the
relevant numbers to things.

== 7 of 16 ==
Date: Mon, Aug 29 2011 7:25 am
From: NT

On Aug 29, 7:21 am, DaveC <inva...@invalid.net> wrote:
> I may be able to obtain a very small 2-pole 240 vac contactor I need rated
> for 50 Hz only.
>
> If I install it in N. America, what's the implication? Is the hold-in
> magnetism less than if it were 60 Hz? Just noisy?
>
> Please don't ask or suggest other sources. This is a very specific device and
> I've not been able to locate other than this.
>
> Thanks,
> Dave

IME relays pull in at in the region of half rated voltage, and dc
ratings are typically about half the voltage of the ac rating, which
gives an idea of how much current is determined by L and how much by
R. Running your relay on 220v 60Hz it will work fine. Contact closing
speed will be slightly slower. Margin will be reduced, but its only
being reduced from enormous to slightly less enormous, so its a non-
issue except in very unusual situations. The vibration tolerance of
the contacts will be little affected in practice; if your environment
is harsh enough to shake the relay contact open, then you've got
bigger worries than contacts crackling.

If instead you meant you would use it on 110v 60Hz, then dont. But you
could use diodes to get a higher dc voltage and use that.

== 8 of 16 ==
Date: Mon, Aug 29 2011 9:22 am
From: "cbarn24050@aol.com"

On Aug 29, 3:25 pm, NT <meow2...@care2.com> wrote:
> On Aug 29, 7:21 am, DaveC <inva...@invalid.net> wrote:
>
> > I may be able to obtain a very small 2-pole 240 vac contactor I need rated
> > for 50 Hz only.
>
> > If I install it in N. America, what's the implication? Is the hold-in
> > magnetism less than if it were 60 Hz? Just noisy?
>
> > Please don't ask or suggest other sources. This is a very specific device and
> > I've not been able to locate other than this.
>
> > Thanks,
> > Dave
>
> IME relays pull in at in the region of half rated voltage, and dc
> ratings are typically about half the voltage of the ac rating, which
> gives an idea of how much current is determined by L and how much by
> R. Running your relay on 220v 60Hz it will work fine. Contact closing
> speed will be slightly slower. Margin will be reduced, but its only
> being reduced from enormous to slightly less enormous, so its a non-
> issue except in very unusual situations. The vibration tolerance of
> the contacts will be little affected in practice; if your environment
> is harsh enough to shake the relay contact open, then you've got
> bigger worries than contacts crackling.
>
> If instead you meant you would use it on 110v 60Hz, then dont. But you
> could use diodes to get a higher dc voltage and use that.
>
> NT

Finally someone comes up with the correct answer.

== 9 of 16 ==
Date: Mon, Aug 29 2011 11:03 am
From: John Fields

On Mon, 29 Aug 2011 07:28:53 -0700 (PDT), NT <meow2222@care2.com>
wrote:

>On Aug 29, 3:03 pm, John Fields <jfie...@austininstruments.com> wrote:
>> On Sun, 28 Aug 2011 23:21:56 -0700, DaveC <inva...@invalid.net> wrote:
>> >I may be able to obtain a very small 2-pole 240 vac contactor I need rated
>> >for 50 Hz only.
>>
>> >If I install it in N. America, what's the implication? Is the hold-in
>> >magnetism less than if it were 60 Hz? Just noisy?
>>
>> >Please don't ask or suggest other sources. This is a very specific device and
>> >I've not been able to locate other than this.
>>
>
>> Not knowing the specifics about the coil makes predicting what will
>> happen at 60Hz difficult.
>>
>> However, assuming that the inductive reactance and resistance of the
>> coil will remain constant at 50 and 60Hz means that the impedance of
>> the coil at 60Hz will be 1.2 times (60Hz/50Hz) what it is at 50Hz.
>
>no, only the L component of the impedance will be 1.2 times as high.

---
Well, that's true, so let's just see how far off I was, by using a
real-world example.

I have an old P&B MR5A here with a 240V 50/60Hz coil.

The coil has a resistance of 4800 ohms, and an open inductance of 14.5
henrys, so it has an impedance of 6616 ohms at 50 Hz, and 7270 ohms at
60 Hz.

7270 - 6616 = 1.1, so my error was 1 part in 11, or a little less than
10%

I can live with that.
---

>> Consequently, the current in the coil at 60Hz will be about 83% of
>> what it is at 50Hz.
>>
>> If that turns out to be a problem, a higher drive voltage could be
>> used in order to increase the current, namely 1.2 times 240V; 288V.
>>
>> That could easily be accomplished using a transformer to boost the
>> 240V mains to 288V, like this: (View with a fixed pitch font.)
>>
>> 240AC>-----+--+
>> | |
>> oP||S
>> R||E
>> I||Co
>> | |
>> | +-----> \
>> | > 288AC TO COIL
>> 240AC>-----+--------> /
>>
>> The transformer would need a 240V primary, a 48V secondary, and a VA
>> rating greater than or equal to the contactor coil's rating.
>
>these are the kind of 'solutions' that happen when people dont put the
>relevant numbers to things.

---
Well, your tone is certainly insulting, while the solution remains
valid, but since the voltage into the coil will only be 11% low, the
transformer secondary will only have to supply 26V instead of 48.

In reality, 24V will be fine.

--
JF

== 10 of 16 ==
Date: Mon, Aug 29 2011 11:55 am
From: "Ian Field"

"NT" <meow2222@care2.com> wrote in message
news:c89fedd0-49ca-49fe-96d2-7d6bb328d22a@n12g2000yqh.googlegroups.com...
On Aug 29, 3:03 pm, John Fields <jfie...@austininstruments.com> wrote:
> On Sun, 28 Aug 2011 23:21:56 -0700, DaveC <inva...@invalid.net> wrote:
> >I may be able to obtain a very small 2-pole 240 vac contactor I need
> >rated
> >for 50 Hz only.
>
> >If I install it in N. America, what's the implication? Is the hold-in
> >magnetism less than if it were 60 Hz? Just noisy?
>
> >Please don't ask or suggest other sources. This is a very specific device
> >and
> >I've not been able to locate other than this.
>

no, only the L component of the impedance will be 1.2 times as high.

these are the kind of 'solutions' that happen when people dont put the
relevant numbers to things.

-----------------------------------------

I'd have accepted the figures as near enough and the transformer with
stacked 48V secondary (wired as an autotransformer) as a convenient way to
do the job.

Even if the figures aren't correct to the nth decimal place, they're
probably within tolerance.

== 11 of 16 ==
Date: Mon, Aug 29 2011 4:44 pm
From: John G

cbarn24050@aol.com wrote on 30/08/2011 :
> On Aug 29, 3:25 pm, NT <meow2...@care2.com> wrote:
>> On Aug 29, 7:21 am, DaveC <inva...@invalid.net> wrote:
>>
>>> I may be able to obtain a very small 2-pole 240 vac contactor I need rated
>>> for 50 Hz only.
>>
>>> If I install it in N. America, what's the implication? Is the hold-in
>>> magnetism less than if it were 60 Hz? Just noisy?
>>> Please don't ask or suggest other sources. This is a very specific device
>>> and I've not been able to locate other than this.
>>> Thanks,
>>> Dave
>>
>> IME relays pull in at in the region of half rated voltage, and dc
>> ratings are typically about half the voltage of the ac rating, which
>> gives an idea of how much current is determined by L and how much by
>> R. Running your relay on 220v 60Hz it will work fine. Contact closing
>> speed will be slightly slower. Margin will be reduced, but its only
>> being reduced from enormous to slightly less enormous, so its a non-
>> issue except in very unusual situations. The vibration tolerance of
>> the contacts will be little affected in practice; if your environment
>> is harsh enough to shake the relay contact open, then you've got
>> bigger worries than contacts crackling.
>>
>> If instead you meant you would use it on 110v 60Hz, then dont. But you
>> could use diodes to get a higher dc voltage and use that.
>>
>> NT
>
> Finally someone comes up with the correct answer.

And actually practical!
Not the wild theoretical solutions that are often way way over the head
of the original inquirer or so impractical as to be useless.

--
John G.

== 12 of 16 ==
Date: Mon, Aug 29 2011 5:28 pm
From: NT

On Aug 29, 7:03 pm, John Fields <jfie...@austininstruments.com> wrote:
> On Mon, 29 Aug 2011 07:28:53 -0700 (PDT), NT <meow2...@care2.com>
> wrote:
>
>
>
> >On Aug 29, 3:03 pm, John Fields <jfie...@austininstruments.com> wrote:
> >> On Sun, 28 Aug 2011 23:21:56 -0700, DaveC <inva...@invalid.net> wrote:
> >> >I may be able to obtain a very small 2-pole 240 vac contactor I need rated
> >> >for 50 Hz only.
>
> >> >If I install it in N. America, what's the implication? Is the hold-in
> >> >magnetism less than if it were 60 Hz? Just noisy?
>
> >> >Please don't ask or suggest other sources. This is a very specific device and
> >> >I've not been able to locate other than this.
>
> >> Not knowing the specifics about the coil makes predicting what will
> >> happen at 60Hz difficult.
>
> >> However, assuming that the inductive reactance and resistance of the
> >> coil will remain constant at 50 and 60Hz means that the impedance of
> >> the coil at 60Hz will be 1.2 times (60Hz/50Hz) what it is at 50Hz.
>
> >no, only the L component of the impedance will be 1.2 times as high.
>
> ---
> Well, that's true, so let's just see how far off I was, by using a
> real-world example.
>
> I have an old P&B MR5A here with a 240V 50/60Hz coil.
>
> The coil has a resistance of 4800 ohms, and an open inductance of 14.5
> henrys, so it has an impedance of 6616 ohms at 50 Hz, and 7270 ohms at
> 60 Hz.
>
> 7270 - 6616 = 1.1, so my error was 1 part in 11, or a little less than
> 10%
>
> I can live with that.
> ---
>
>
>
> >> Consequently, the current in the coil at 60Hz will be about 83% of
> >> what it is at 50Hz.
>
> >> If that turns out to be a problem, a higher drive voltage could be
> >> used in order to increase the current, namely 1.2 times 240V; 288V.
>
> >> That could easily be accomplished using a transformer to boost the
> >> 240V mains to 288V, like this: (View with a fixed pitch font.)
>
> >> 240AC>-----+--+
> >> | |
> >> oP||S
> >> R||E
> >> I||Co
> >> | |
> >> | +-----> \
> >> | > 288AC TO COIL
> >> 240AC>-----+--------> /
>
> >> The transformer would need a 240V primary, a 48V secondary, and a VA
> >> rating greater than or equal to the contactor coil's rating.
>
> >these are the kind of 'solutions' that happen when people dont put the
> >relevant numbers to things.
>

> Well, your tone is certainly insulting, while the solution remains
> valid, but since the voltage into the coil will only be 11% low, the
> transformer secondary will only have to supply 26V instead of 48.
>
> In reality, 24V will be fine.

The relay has a voltage margin of around 50%, the mains supply wont
vary more than 10%, so the transformer is of no use.

== 13 of 16 ==
Date: Mon, Aug 29 2011 5:30 pm
From: NT

> Well, your tone is certainly insulting,

yes, my apologies.

== 14 of 16 ==
Date: Mon, Aug 29 2011 5:59 pm
From: "cbarn24050@aol.com"

On Aug 30, 12:44 am, John G <greent...@ozemail.com.au> wrote:
> cbarn24...@aol.com wrote on 30/08/2011 :
> > Finally someone comes up with the correct answer.
>
> And actually practical!
> Not the wild theoretical solutions that are often way way over the head
> of the original inquirer or so impractical as to be useless.
>
> --
> John G.- Hide quoted text -
>

Oh they don't do practical here! It's rare for them to get it right
either, this thread is no exception. Some of them even advertise their
place of work! I wonder how much business that has cost them.

== 15 of 16 ==
Date: Mon, Aug 29 2011 6:07 pm
From: Spehro Pefhany

On Mon, 29 Aug 2011 07:25:23 -0700 (PDT), the renowned NT
<meow2222@care2.com> wrote:

>On Aug 29, 7:21 am, DaveC <inva...@invalid.net> wrote:
>> I may be able to obtain a very small 2-pole 240 vac contactor I need rated
>> for 50 Hz only.
>>
>> If I install it in N. America, what's the implication? Is the hold-in
>> magnetism less than if it were 60 Hz? Just noisy?
>>
>> Please don't ask or suggest other sources. This is a very specific device and
>> I've not been able to locate other than this.
>>
>> Thanks,
>> Dave
>
>IME relays pull in at in the region of half rated voltage, and dc
>ratings are typically about half the voltage of the ac rating, which
>gives an idea of how much current is determined by L and how much by
>R. Running your relay on 220v 60Hz it will work fine. Contact closing
>speed will be slightly slower. Margin will be reduced, but its only
>being reduced from enormous to slightly less enormous, so its a non-
>issue except in very unusual situations.

Well, high ambient temperature and low input voltage. May not be that
unusual. I've seen it happen more than once, particularly in
industrial situations where ambient temperatures can be relatively
high.

I even had to wire an autotransformer into a domestic elevator control
panel because the designer ignored the necessity of allowing for
voltage drop when the drive motor started, which caused chattering of
the AC contactor even in a climate-controlled 22°C environment.

> The vibration tolerance of
>the contacts will be little affected in practice; if your environment
>is harsh enough to shake the relay contact open, then you've got
>bigger worries than contacts crackling.

Since the OP didn't describe the environment.. it may or may not be.
For aircraft work (yes, some is 60Hz) it would be a really good idea
to check. If it's sitting on a subpanel with the control cabinet
bolted to the floor rather than to an OBI punch press, not a big deal.

>If instead you meant you would use it on 110v 60Hz, then dont. But you
>could use diodes to get a higher dc voltage and use that.
>
>
>NT

== 16 of 16 ==
Date: Mon, Aug 29 2011 7:55 pm
From: David Lesher

DaveC <invalid@invalid.net> writes:

>I may be able to obtain a very small 2-pole 240 vac contactor I need rated
>for 50 Hz only.

>If I install it in N. America, what's the implication? Is the hold-in
>magnetism less than if it were 60 Hz? Just noisy?

It will be happy. If it were a 60Hz on 50, it would not be as happy.

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

==============================================================================
TOPIC: OT: Tek 465
http://groups.google.com/group/sci.electronics.repair/t/b9f473fde6856891?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Aug 29 2011 9:23 am
From: Jim Yanik

Jeff Liebermann <jeffl@cruzio.com> wrote in
news:4pnl57568hr7j9pumqdvcn5k35gcos1mvc@4ax.com:

> On Sun, 28 Aug 2011 18:34:22 -0500, Jim Yanik <jyanik@abuse.gov>
> wrote:
>
>>My carbonized hole was the HV osc xstr,a TIP31C.
>
> The TIP31c is good for 100VDC. That's right on the border where I
> would worry about any remaining carbonized epoxy causing a conduction
> path. Good to know it worked.

the TIP-31C supply rail was 40v unreg;the reason why it burned up is the
+5v rail main filter cap ESR shot up,and the switcher drove it back up to
5v and all the other supplies went way higher;the +40 went to over 60vDC.
then the HV-osc xstr over dissipated,and burned up the PCB.
>
>>I never had any problem with epoxy shrinkage. I used a clear epoxy
>>from Hysol.
>>Now I would use my RAKA boat-building epoxy with fumed silica
>>filler.great stuff.
>
> Silica filler, as in sand?

no,it's a white superfine powder used in epoxy mixes,for "filling the
weave" after fiberglassing your boat.It makes the epoxy thicker,and hard as
a rock. Nothing like sand (and a lot cleaner!).
Go to Systemthree.com,and read(free download!) their Epoxy Book,it's VERY
informative about using epoxies and fillers. I use wood flour,fumed
silica,phenolic microballoons,and chopped plastic fibers for
fillers,depending on the application. chopped glass fiber is also
available,but I've never used it.

I began using this stuff when I briefly returned to large model
rocketry;you need strong body tubes and fin attachments with the higher
power rocket motors now available.Fun,but an expensive hobby.

> Well, that will give it considerable
> hardness and strength. However, I don't think that will be necessary
> to repair a PCB. I was dealing with a rather large hole, about 3/4"
> in diameter. I wanted to make sure than any applied pressure would
> not crack the epoxy. So, I added fiberglass matt reinforcing.

the holes I filled were about 0.5" in diameter or less.
>
>>> Did you notice the TAS 465 scope in the pile to be fixed?
>>><http://802.11junk.com/jeffl/crud/scopes-to-be-fixed.jpg>
>>
>>Missed that. Never worked on one.
>
> They look fairly nice inside and seem easy to work. Unfortunately,
> there are plenty of proprietary parts.
>
>>> It lights up, runs, but the beam and alpha are stuck on the left
>>> side of the screen. Vertical seems to be working but it's difficult
>>> to tell with the beam off the screen. Obviously, a horizontal amp
>>> problem.
>>
>>could also be a sweep problem;sweep triggered,but sweep gen not
>>ramping. might just be a CRT deflection pin lead fell off. I've seen
>>them get loose,and get shaken off in moving the scope.
>
> I checked all the loose connection possibilities. All the scope
> deflections leads have voltage. I don't think it's a trigger problem
> because the various text labels that should show up on the screen, are
> also stuck on the left side. I can see them sorta move when I
> randomly push buttons, so I know they're functional, just not
> displaying. I'll figure it out eventually. Project for tonite is yet
> another blown power supply in an IFR-1500 service monitor. Great
> monitor, disgusting power supply design.
>
>>> One of the T922 scopes on top of the pile works. Which one, I
>>> forgot. The other has a blown flyback xformer. I haven't found a
>>> substitute yet.
>>
>>I always liked the T922/32/35/442. Not the T912.
>
> Yep. Not a bad scope, but the 922 is only good for 15Mhz. In these
> daze of 100MHz scopes, it's kinda limiting.

Nice thing is that they don't use -any- TEK-made ICs.
but they still have those low-pressure cam switch contacts,I'm surprised
any are still working. the plastic degrades and the little gold finger
contact falls off the spring part.No replacements available,either,AFAIK.
>
>>> The two on the bottom of the pile are both HP 1740A 100MHz scopes.
>>> Both have power supply problems, which are probably bad
>>> electrolytics. I'm too lazy to fix them.
>>>
>>> There are also at least 4 more assorted scopes around the house, and
>>> 3 more in the office, some of which work.
>
>>WOW,most people only have one or two scopes..... :-)
>
> I forgot to mention 6ea Tek 5110 scopes with 5A18 vertical plug-ins.
> They're rack mounted into various ham radio repeaters, hi-fi racks,
> and at radio sites. I got tired of dragging a scope with me every
> time I needed to do some repairs. So, I just added one into every
> rack where I thought it might be useful. Works great, except that all
> the other techs steal my scope probes.
>
>>are you fixing them for friends,or the occasional sale?
>
> I have friends and I have customers. The difference is that the
> customers pay me. Otherwise, they're the same.
>
> Some of the better scopes were intended for me to use. Literally,
> every scope required some form of repair or rework. I tend to buy
> broken things, and fix them. (Don't ask me why I have 6 chain saws).
> I plan to sell them eventually, but have not had the time or incentive
> to fix any of them[1]. Diving into the shop, I see a Tek 2205, HP
> 182C, and Tek 213 scope/DVM, all of which are in need of something. I
> didn't know I had that many scopes. Time to find some friends, err...
> customers, and get rid of them. Otherwise, I'll just repupose my shop
> as a museum.

213 and all 200 series scopes are prone to having the plastic locator pins
in the case halves break or pull out under shock,and then the PCBs shift
around,and the pins spread open the female connectors,the little leaf
springs fall out and short things out.It's still a nice little scope,only
1 MHZ BW,but has the nifty on-screen DMM. TEK field service people used to
use(and abuse) them.
>
> [1] That may happen soon, as the computah repair biz is really slow.
> What I usually do is take a few days off, and diagnose everything and
> order parts. About 2 weeks later, when the parts arrive late, I do
> assembly line repair on everything possible. I've done this several
> times in the past and it works quite well for me. The problem is
> finding the uninterrupted time.
>
> Incidentally, I just found a box of Tek repair parts, dating back to
> the 1970's era. Nuvistors, tubes, semiconductors, etc. There's an
> inventory list, but the boxes have probably been pillaged. Any
> interest?

No,but thanks anyways.

><http://802.11junk.com/jeffl/crud/Tek-Parts.jpg>
> There are 4 similar, but smaller plastic boxes stuffed with parts.

--
Jim Yanik
jyanik
at
localnet
dot com

== 2 of 2 ==
Date: Mon, Aug 29 2011 10:32 am
From: "bg"

>
> Incidentally, I just found a box of Tek repair parts, dating back to
> the 1970's era. Nuvistors, tubes, semiconductors, etc. There's an
> inventory list, but the boxes have probably been pillaged. Any
> interest?
> <http://802.11junk.com/jeffl/crud/Tek-Parts.jpg>
> There are 4 similar, but smaller plastic boxes stuffed with parts.
> --
> Jeff Liebermann jeffl@cruzio.com
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 http://802.11junk.com
> Skype: JeffLiebermann AE6KS 831-336-2558

I've got a 465 that needs both of the dual FET buffer chips that are in the
verticle front end (right after the attenuators). I've heard that the 2n5911
is similiar but I'd have to buy hundreds of them which is way beyond what a
used parts scope would cost. Do you have any for sale?
bg

==============================================================================
TOPIC: Tektronix 7603
http://groups.google.com/group/sci.electronics.repair/t/efb86f5dc14fc24b?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Aug 29 2011 10:57 am
From: Reinhard Zwirner

Jeff Urban schrieb:
> The old 7613 died. [...]

Hi Jeff,

Ask for help in the VERY helpful "TekScopes" Yahoo group.

HTH

Reinhard

==============================================================================
TOPIC: How to resolder a cold solder connection?
http://groups.google.com/group/sci.electronics.repair/t/46868719284715b1?hl=en
==============================================================================

== 1 of 4 ==
Date: Mon, Aug 29 2011 12:20 pm
From: micky

On Sun, 28 Aug 2011 22:15:11 -0700, Winston <Winston@BigBrother.net>
wrote:

>
>> Does that also have to be R, RMA, or RA?
>
>Yup.
>Most specifically NOT 'acid' or 'plumbing' flux.
>Sorry for shouting but we don't want your relay
>to turn green and fall apart.

Gotcha! You and Smitty Two.

>--Winston

== 2 of 4 ==
Date: Mon, Aug 29 2011 12:42 pm
From: Phil Hobbs

On 08/29/2011 03:20 PM, micky wrote:
> On Sun, 28 Aug 2011 22:15:11 -0700, Winston<Winston@BigBrother.net>
> wrote:
>
>>
>>> Does that also have to be R, RMA, or RA?
>>
>> Yup.
>> Most specifically NOT 'acid' or 'plumbing' flux.
>> Sorry for shouting but we don't want your relay
>> to turn green and fall apart.
>
> Gotcha! You and Smitty Two.
>
>> --Winston
>

I'd put in a plug for RA flux. I have a lot of old parts that I still
use a lot (e.g. over 10,000 RN55C resistors), and RA flux makes them
solder like new.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

== 3 of 4 ==
Date: Mon, Aug 29 2011 1:15 pm
From: micky

On Mon, 29 Aug 2011 15:42:00 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 08/29/2011 03:20 PM, micky wrote:
>> On Sun, 28 Aug 2011 22:15:11 -0700, Winston<Winston@BigBrother.net>
>> wrote:
>>
>>>
>>>> Does that also have to be R, RMA, or RA?
>>>
>>> Yup.
>>> Most specifically NOT 'acid' or 'plumbing' flux.
>>> Sorry for shouting but we don't want your relay
>>> to turn green and fall apart.
>>
>> Gotcha! You and Smitty Two.
>>
>>> --Winston
>>
>
>I'd put in a plug for RA flux. I have a lot of old parts that I still
>use a lot (e.g. over 10,000 RN55C resistors), and RA flux makes them
>solder like new.

Okay, I'll see what they sell.

>Cheers
>
>Phil Hobbs

== 4 of 4 ==
Date: Mon, Aug 29 2011 4:12 pm
From: Winston

Phil Hobbs wrote:
> On 08/29/2011 03:20 PM, micky wrote:
>> On Sun, 28 Aug 2011 22:15:11 -0700, Winston<Winston@BigBrother.net>
>> wrote:
>>
>>>
>>>> Does that also have to be R, RMA, or RA?
>>>
>>> Yup.
>>> Most specifically NOT 'acid' or 'plumbing' flux.
>>> Sorry for shouting but we don't want your relay
>>> to turn green and fall apart.
>>
>> Gotcha! You and Smitty Two.
>>
>>> --Winston
>>
>
> I'd put in a plug for RA flux. I have a lot of old parts that I still
> use a lot (e.g. over 10,000 RN55C resistors), and RA flux makes them
> solder like new.

That'll work!
My fave Kester 186 is RMA and it does a stellar
job as well.

--Winston

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