Can I get peoples opinions on and suggestions of lay / informal remedies to
intermittent faults.
My /one suggestion is "bouncing", such as with a soft surface - e.g. a bed.
"Grasp device at one end, 'bounce' onto and off soft surface. Plug in and
try again".
News Reader wrote:
> Hi,
>
> Can I get peoples opinions on and suggestions of lay / informal
> remedies to intermittent faults.
>
> My /one suggestion is "bouncing", such as with a soft surface - e.g.
> a bed. "Grasp device at one end, 'bounce' onto and off soft surface.
> Plug in and try again".
How very refined.... Much less drastic than the common person's "Give it a
bloody good kicking."
If urgency isn't an issue, I've found that that repeated nagging with escalating
threats sometimes serves.
"cybuerke" <cybuerke@PLMgooglemail.com> wrote in message
news:f1p361$sic$1@news.freedom2surf.net...
> News Reader wrote:
>> Hi,
>>
>> Can I get peoples opinions on and suggestions of lay / informal
>> remedies to intermittent faults.
>>
>> My /one suggestion is "bouncing", such as with a soft surface - e.g.
>> a bed. "Grasp device at one end, 'bounce' onto and off soft surface.
>> Plug in and try again".
>
> How very refined.... Much less drastic than the common person's "Give it
> a bloody good kicking."
>
> If urgency isn't an issue, I've found that that repeated nagging with
> escalating threats sometimes serves.
>
The problem lies in the frustration circuit which is present in all
electronic equipment. It reduces performance in direct proportion to the
perceived frustration of the user. You should try sitting back with a cup
of tea and pretending that you don't really want to go on line anyway.
;o)
--
Keith Willcocks
(If you can't laugh at life, it ain't worth living!)
On Tue, 8 May 2007 08:45:40 +0100, Keith Willcocks wrote:
> "cybuerke" <cybuerke@PLMgooglemail.com> wrote in message
> news:f1p361$sic$1@news.freedom2surf.net...
>> News Reader wrote:
>>> Hi,
>>>
>>> Can I get peoples opinions on and suggestions of lay / informal
>>> remedies to intermittent faults.
>>>
>>> My /one suggestion is "bouncing", such as with a soft surface - e.g.
>>> a bed. "Grasp device at one end, 'bounce' onto and off soft surface.
>>> Plug in and try again".
>>
>> How very refined.... Much less drastic than the common person's "Give it
>> a bloody good kicking."
>>
>> If urgency isn't an issue, I've found that that repeated nagging with
>> escalating threats sometimes serves.
>>
>
> The problem lies in the frustration circuit which is present in all
> electronic equipment. It reduces performance in direct proportion to the
> perceived frustration of the user. You should try sitting back with a cup
> of tea and pretending that you don't really want to go on line anyway.
> ;o)
This circuit also senses the proximity of any qualified person and
immediately suspends the fault until the threat of repair has passed.
--
Peter.
If you can do it today, you didn't put off enough yesterday.
News Reader wrote:
> Hi,
>
> Can I get peoples opinions on and suggestions of lay / informal remedies to
> intermittent faults.
>
> My /one suggestion is "bouncing", such as with a soft surface - e.g. a bed.
> "Grasp device at one end, 'bounce' onto and off soft surface. Plug in and
> try again".
>
> Thanks.
>
>
> Best wishes,
>
>
>
> News Reader
>
>
Hit it with a "virtual" stick, much better than threast.
On Tue, 08 May 2007 08:35:28 GMT, DH <nowhere@anywhere.com> wrote:
>News Reader wrote:
>> Hi,
>>
>> Can I get peoples opinions on and suggestions of lay / informal remedies to
>> intermittent faults.
>>
>> My /one suggestion is "bouncing", such as with a soft surface - e.g. a bed.
>> "Grasp device at one end, 'bounce' onto and off soft surface. Plug in and
>> try again".
>>
>> Thanks.
>>
>>
>> Best wishes,
>>
>>
>>
>> News Reader
>>
>>
>
>Hit it with a "virtual" stick, much better than threast.
>
>DH
Intermiitent faults can often be due to soldered joint or component
problems.
These often depend on temperature. The particular method(s) I have
used have depended on the fault type, these are:-
1. Tap printed circuit boards, in various places, with the non-metalic
part of a screwdriver. This method can be used, gently, on thermionic
devices, such as on the neck of a CRT, if that is suspected.
2. If intermittent noise, try squirting 'freezer' aerosol on
individual components, that you have homed in on, by studying the
circuit/making measurements - i.e. standard fault finding techniques.
3. Use a hairdryer on suspect areas, to raise the temperature, if you
suspect a temperature driven fault.
4.Put it on 'soak' - i.e. give it time, get on with something else but
kep an eye on the performance of the device under test.
If the fault fails to materialise then, at least, clean up the
circuit boards and make sure any switches etc.are cleaned, where
appropriate. Hope this helps!
In message <CNydnZ37cN84t93bnZ2dnUVZ8saonZ2d@bt.com>, Keith Willcocks
<buccaneer@invalidaddress.inv> writes
>
>"cybuerke" <cybuerke@PLMgooglemail.com> wrote in message
>news:f1p361$sic$1@news.freedom2surf.net...
>> News Reader wrote:
>>> Hi,
>>>
>>> Can I get peoples opinions on and suggestions of lay / informal
>>> remedies to intermittent faults.
>>>
>>> My /one suggestion is "bouncing", such as with a soft surface - e.g.
>>> a bed. "Grasp device at one end, 'bounce' onto and off soft surface.
>>> Plug in and try again".
>>
>> How very refined.... Much less drastic than the common person's "Give it
>> a bloody good kicking."
>>
>> If urgency isn't an issue, I've found that that repeated nagging with
>> escalating threats sometimes serves.
>>
>
>
>The problem lies in the frustration circuit which is present in all
>electronic equipment. It reduces performance in direct proportion to the
>perceived frustration of the user. You should try sitting back with a cup
>of tea and pretending that you don't really want to go on line anyway.
As a former maintenance engineer I was completely convinced that a fault
occupied a point in space. If you replaced faulty equipment then the new
equipment showed the same fault and the old gear was perfectly
serviceable.
DH wrote:
> News Reader wrote:
>> Hi,
>>
>> Can I get peoples opinions on and suggestions of lay / informal
>> remedies to intermittent faults.
>>
>> My /one suggestion is "bouncing", such as with a soft surface - e.g. a
>> bed. "Grasp device at one end, 'bounce' onto and off soft surface.
>> Plug in and try again".
> Hit it with a "virtual" stick, much better than threast.
>
> DH
May I counter-suggest the Baton of Health and Safety. This
government-approved replacement of the commonplace "stick" is a safe and
environmentally-friendly length of foam with no corners, flammable
materials or sexist/ageist/racist comments inscribed on it (in case of
offence). It is unlikely to damage anything that comes in contact with it,
nor subject the user to any repetitive strain injury, noise damage or risk
of poking one's eye out. It cannot be smoked, so is in compliance with
recent anti-smoking legislation.
"News Reader" <no@email.invalid> wrote in message
news:f1onnt$q80$1@inews.gazeta.pl...
>
> Hi,
>
> Can I get peoples opinions on and suggestions of lay / informal remedies
> to intermittent faults.
>
> My /one suggestion is "bouncing", such as with a soft surface - e.g. a
> bed. "Grasp device at one end, 'bounce' onto and off soft surface. Plug in
> and try again".
>
In the early '90s we were supplying BBC model B's to Pharmacies.
The PSU suffered from dry-joints and the official trouble-shooting
guide said something like this.
"If the computer fails to start up, lift up the entire machine to a height
of four inches above the bench, and let go"
On Tue, 8 May 2007 15:56:51 +0100, "Graham" <me@privacy.com> wrote:
|!
|!"News Reader" <no@email.invalid> wrote in message
|!news:f1onnt$q80$1@inews.gazeta.pl...
|!>
|!> Hi,
|!>
|!> Can I get peoples opinions on and suggestions of lay / informal remedies
|!> to intermittent faults.
|!>
|!> My /one suggestion is "bouncing", such as with a soft surface - e.g. a
|!> bed. "Grasp device at one end, 'bounce' onto and off soft surface. Plug in
|!> and try again".
|!>
|!
|!In the early '90s we were supplying BBC model B's to Pharmacies.
|!The PSU suffered from dry-joints and the official trouble-shooting
|!guide said something like this.
|!
|!"If the computer fails to start up, lift up the entire machine to a height
|!of four inches above the bench, and let go"
I saw this when I was in the RAF. There was a very *large* Senior Tech
Electrical who was a whizz on the Comet aircraft. When he had a snag he
told his little SAC to go and jump by the ??th window on the right/left as
the case may be. The SAC did that and came back. If the snag was still
there the above was repeated. If the snag was still there he heaved
himself out of the Engineers chair trundled down the Comet and jumped by
the ??window on the left/right. The Comet shuddered. The snag
disappeared. It was a sticking relay. He knew where every relay was and
cleared them as above.
--
Dave Fawthrop <sf hyphenologist.co.uk> 165 *Free* SF ebooks.
165 Sci Fi books on CDROM, from Project Gutenberg http://www.gutenberg.org/wiki/Main_Page Completely Free to any
address in the UK. Contact me on the *above* email address.
DH wrote:
> News Reader wrote:
>> Hi,
>>
>> Can I get peoples opinions on and suggestions of lay / informal
>> remedies to intermittent faults.
>>
>> My /one suggestion is "bouncing", such as with a soft surface - e.g. a
>> bed. "Grasp device at one end, 'bounce' onto and off soft surface.
>> Plug in and try again".
>>
>> Thanks.
>>
>>
>> Best wishes,
>>
>>
>>
>> News Reader
>>
>
> Hit it with a "virtual" stick, much better than threast.
>
> DH
Actually I used to work for Decca in the early 70s at Bridgnorth making colour
TVs. As part of the chassis line test procedure, we were instructed to hit the
metalwork of the chassis with large rubber mallets, specifically to show up
any faults.
> "News Reader" <no@email.invalid> wrote in message
> news:f1onnt$q80$1@inews.gazeta.pl...
>>
>> Hi,
>>
>> Can I get peoples opinions on and suggestions of lay / informal remedies
>> to intermittent faults.
>>
>> My /one suggestion is "bouncing", such as with a soft surface - e.g. a
>> bed. "Grasp device at one end, 'bounce' onto and off soft surface. Plug in
>> and try again".
>>
>
> In the early '90s we were supplying BBC model B's to Pharmacies.
> The PSU suffered from dry-joints and the official trouble-shooting
> guide said something like this.
>
> "If the computer fails to start up, lift up the entire machine to a height
> of four inches above the bench, and let go"
So you hadn't gone metric?
--
Peter.
If you can do it today, you didn't put off enough yesterday.
On Tue, 8 May 2007 12:49:37 +0100, M. J. Powell wrote:
> In message <CNydnZ37cN84t93bnZ2dnUVZ8saonZ2d@bt.com>, Keith Willcocks
> <buccaneer@invalidaddress.inv> writes
>>
>>"cybuerke" <cybuerke@PLMgooglemail.com> wrote in message
>>news:f1p361$sic$1@news.freedom2surf.net...
>>> News Reader wrote:
>>>> Hi,
>>>>
>>>> Can I get peoples opinions on and suggestions of lay / informal
>>>> remedies to intermittent faults.
>>>>
>>>> My /one suggestion is "bouncing", such as with a soft surface - e.g.
>>>> a bed. "Grasp device at one end, 'bounce' onto and off soft surface.
>>>> Plug in and try again".
>>>
>>> How very refined.... Much less drastic than the common person's "Give it
>>> a bloody good kicking."
>>>
>>> If urgency isn't an issue, I've found that that repeated nagging with
>>> escalating threats sometimes serves.
>>>
>>
>>
>>The problem lies in the frustration circuit which is present in all
>>electronic equipment. It reduces performance in direct proportion to the
>>perceived frustration of the user. You should try sitting back with a cup
>>of tea and pretending that you don't really want to go on line anyway.
>
> As a former maintenance engineer I was completely convinced that a fault
> occupied a point in space. If you replaced faulty equipment then the new
> equipment showed the same fault and the old gear was perfectly
> serviceable.
>
> Mike
It's quite a large space and if also occupied by said me the fault is often
displaced slightly to just outside the equipment.
Could also be time-based.
--
Peter.
If you can do it today, you didn't put off enough yesterday.
"Brian A" <no_spam_bca1000@hotmail.com> wrote in message
news:4mh043th6qo6035g5lkobpjhboi6n29ql9@4ax.com...
> On Tue, 08 May 2007 08:35:28 GMT, DH <nowhere@anywhere.com> wrote:
>
>>News Reader wrote:
>>> Hi,
>>>
>>> Can I get peoples opinions on and suggestions of lay / informal remedies
>>> to
>>> intermittent faults.
>>>
>>> My /one suggestion is "bouncing", such as with a soft surface - e.g. a
>>> bed.
>>> "Grasp device at one end, 'bounce' onto and off soft surface. Plug in
>>> and
>>> try again".
>>>
>>> Thanks.
>>>
>>>
>>> Best wishes,
>>>
>>>
>>>
>>> News Reader
>>>
>>>
>>
>>Hit it with a "virtual" stick, much better than threast.
>>
>>DH
> Intermiitent faults can often be due to soldered joint or component
> problems.
> These often depend on temperature. The particular method(s) I have
> used have depended on the fault type, these are:-
> 1. Tap printed circuit boards, in various places, with the non-metalic
> part of a screwdriver. This method can be used, gently, on thermionic
> devices, such as on the neck of a CRT, if that is suspected.
> 2. If intermittent noise, try squirting 'freezer' aerosol on
> individual components, that you have homed in on, by studying the
> circuit/making measurements - i.e. standard fault finding techniques.
> 3. Use a hairdryer on suspect areas, to raise the temperature, if you
> suspect a temperature driven fault.
> 4.Put it on 'soak' - i.e. give it time, get on with something else but
> kep an eye on the performance of the device under test.
>
> If the fault fails to materialise then, at least, clean up the
> circuit boards and make sure any switches etc.are cleaned, where
> appropriate. Hope this helps!
>
All those are good.
I worked in a mainframe design lab in the 1960s using TTL and wrapped
backplane joints. Other techniques we used were:
- look for dry joints - any not shiny and with a dusty appearance - and
resolder them.
- wiggle all the wrapped wiring with a stiff brush,
- alter the supply voltage (but within limits). TTL had a tolerance of
4.75 to 5.25 volts but I liked to weed out anything which failed if I took
it down to 4.3 volts.
- flex or twist the printed circuit boards slightly - a real killer for
intermittents but take care of high voltages and static sensitive stuff.
- rattle all the boards. After visiting and fixing one troublesome
system my boss asked me whether I'd rattled the boards. I had, with a
plastic connector cover, but I was reprimanded for not using a hammer. On
a subsequent occasion I was again reprimanded for not physically breaking
any boards with the said hammer!!
Not sure that's particularly good if you want to rely on a warranty though.
In message <f1q2vt$sv6$1@news.datemas.de>, Graham <me@privacy.com>
writes
>
>"News Reader" <no@email.invalid> wrote in message
>news:f1onnt$q80$1@inews.gazeta.pl...
>>
>> Hi,
>>
>> Can I get peoples opinions on and suggestions of lay / informal remedies
>> to intermittent faults.
>>
>> My /one suggestion is "bouncing", such as with a soft surface - e.g. a
>> bed. "Grasp device at one end, 'bounce' onto and off soft surface. Plug in
>> and try again".
>>
>
>In the early '90s we were supplying BBC model B's to Pharmacies.
>The PSU suffered from dry-joints and the official trouble-shooting
>guide said something like this.
>
>"If the computer fails to start up, lift up the entire machine to a height
>of four inches above the bench, and let go"
The GPO Pulse & Bar generator had, in the manual, a sentence which said
"It is quite possible that every component will test within spec but the
equipment fail to work."
"Phil B" <phil.remove.brady@hotmail.co.uk> wrote in message
news:49idnXl3c44gJd3bnZ2dnUVZ8qqlnZ2d@bt.com...
>
> "Brian A" <no_spam_bca1000@hotmail.com> wrote in message
> news:4mh043th6qo6035g5lkobpjhboi6n29ql9@4ax.com...
>> On Tue, 08 May 2007 08:35:28 GMT, DH <nowhere@anywhere.com> wrote:
>>
>>>News Reader wrote:
>>>> Hi,
>>>>
>>>> Can I get peoples opinions on and suggestions of lay / informal
>>>> remedies to
>>>> intermittent faults.
>>>>
>>>> My /one suggestion is "bouncing", such as with a soft surface - e.g. a
>>>> bed.
>>>> "Grasp device at one end, 'bounce' onto and off soft surface. Plug in
>>>> and
>>>> try again".
>>>>
>>>> Thanks.
>>>>
>>>>
>>>> Best wishes,
>>>>
>>>>
>>>>
>>>> News Reader
>>>>
>>>>
>>>
>>>Hit it with a "virtual" stick, much better than threast.
>>>
>>>DH
>> Intermiitent faults can often be due to soldered joint or component
>> problems.
>> These often depend on temperature. The particular method(s) I have
>> used have depended on the fault type, these are:-
>> 1. Tap printed circuit boards, in various places, with the non-metalic
>> part of a screwdriver. This method can be used, gently, on thermionic
>> devices, such as on the neck of a CRT, if that is suspected.
>> 2. If intermittent noise, try squirting 'freezer' aerosol on
>> individual components, that you have homed in on, by studying the
>> circuit/making measurements - i.e. standard fault finding techniques.
>> 3. Use a hairdryer on suspect areas, to raise the temperature, if you
>> suspect a temperature driven fault.
>> 4.Put it on 'soak' - i.e. give it time, get on with something else but
>> kep an eye on the performance of the device under test.
>>
>> If the fault fails to materialise then, at least, clean up the
>> circuit boards and make sure any switches etc.are cleaned, where
>> appropriate. Hope this helps!
>>
>
> All those are good.
> I worked in a mainframe design lab in the 1960s using TTL and wrapped
> backplane joints. Other techniques we used were:
> - look for dry joints - any not shiny and with a dusty appearance - and
> resolder them.
> - wiggle all the wrapped wiring with a stiff brush,
> - alter the supply voltage (but within limits). TTL had a tolerance of
> 4.75 to 5.25 volts but I liked to weed out anything which failed if I took
> it down to 4.3 volts.
> - flex or twist the printed circuit boards slightly - a real killer for
> intermittents but take care of high voltages and static sensitive stuff.
> - rattle all the boards. After visiting and fixing one troublesome
> system my boss asked me whether I'd rattled the boards. I had, with a
> plastic connector cover, but I was reprimanded for not using a hammer.
> On a subsequent occasion I was again reprimanded for not physically
> breaking any boards with the said hammer!!
> Not sure that's particularly good if you want to rely on a warranty
> though.
>
> Hope that helps.
>
> Phil
>
>> Remove 'no_spam_' from email address.
>
>
>
>
Hi,
On a slightly more serious note... most of that certainly sounds very good.
Not so sure about the employers fervent hammer fixation... but otherwise all
sounds good :) .
I think with more shock sensitive equipment, or anything you wish to shock
but without such direct impact or abrasive contact, the bouncing method is
quite a good intermediary step. Obviously, if that fails, you can always
escalate to the higher impact effect of knocking into or "bouncing" or
dropping onto a hard surface.
Of course, the reality is that the proper approach, is to use test equipment
and proper fault testing methods.
However, that is not always possible, and equally, you may be aware of the
faulty component and just be trying to prolong its operation. Hard drives
interestingly whilst hating high g shock, often enough seem to appreciate or
rejuvenate on a middling motion effect (bouncing, etc.).
"Dr Teeth" <no.email.here.please@tardis.com> wrote in message
news:1ln143d7ja4tjsrgc2v3ihn1dbbot4fr06@4ax.com...
>I was just thinking how wonderful life was, when "News Reader"
> <no@email.invalid> opened his gob and said:
>
>>Can I get peoples opinions on and suggestions of lay / informal remedies
>>to
>>intermittent faults.
>
> Bang your head against the wall and stick your tongue in a mains
> socket until the problem does not recur, or becomes permanent (i.e.
> non-intermittent).
>
> --
> Cheers,
>
> Guy
>
> ** Stress - the condition brought about by having to
> ** resist the temptation to beat the living daylights
> ** out of someone who richly deserves it.
Hi,
Hmmm.... not sure if I have totally got this one understood correctly... but
it sounds good :)
I was just thinking how wonderful life was, when "News Reader"
<no@email.invalid> opened his gob and said:
>Can I get peoples opinions on and suggestions of lay / informal remedies to
>intermittent faults.
Bang your head against the wall and stick your tongue in a mains
socket until the problem does not recur, or becomes permanent (i.e.
non-intermittent).
--
Cheers,
Guy
** Stress - the condition brought about by having to
** resist the temptation to beat the living daylights
** out of someone who richly deserves it.
>
> "Dr Teeth" <no.email.here.please@tardis.com> wrote in message
> news:1ln143d7ja4tjsrgc2v3ihn1dbbot4fr06@4ax.com...
>>I was just thinking how wonderful life was, when "News Reader"
>> <no@email.invalid> opened his gob and said:
>>
>>>Can I get peoples opinions on and suggestions of lay / informal
>>>remedies to intermittent faults.
>>
>> Bang your head against the wall and stick your tongue in a mains
>> socket until the problem does not recur, or becomes permanent (i.e.
>> non-intermittent).
>>
>
> Hmmm.... not sure if I have totally got this one understood
> correctly... but it sounds good :)
>
>
It may sound good, but it will taste out of this world
In message <HKChsCDRPGQGFwir@pickmere.demon.co.uk>, M. J. Powell
<mike@pickmere.demon.co.uk> writes
>If you replaced faulty equipment then the new equipment showed the same
>fault and the old gear was perfectly serviceable.
>
I had an old electric drill once. It started to become intermittent. I
took it to pieces, checked the mains lead, but couldn't find anything
wrong. But still the fault persisted, so I bought a new drill.
The new drill exhibited exactly the same intermittent operation. I then
decided to look at the mains extension cable ....:-))
"M. J. Powell" <mike@pickmere.demon.co.uk> wrote in message
news:BQkAKrHIDNQGFwS6@pickmere.demon.co.uk...
> In message <f1q2vt$sv6$1@news.datemas.de>, Graham <me@privacy.com> writes
>>
>>"News Reader" <no@email.invalid> wrote in message
>>news:f1onnt$q80$1@inews.gazeta.pl...
>>>
>>> Hi,
>>>
>>> Can I get peoples opinions on and suggestions of lay / informal remedies
>>> to intermittent faults.
>>>
>>> My /one suggestion is "bouncing", such as with a soft surface - e.g. a
>>> bed. "Grasp device at one end, 'bounce' onto and off soft surface. Plug
>>> in
>>> and try again".
>>>
>>
>>In the early '90s we were supplying BBC model B's to Pharmacies.
>>The PSU suffered from dry-joints and the official trouble-shooting
>>guide said something like this.
>>
>>"If the computer fails to start up, lift up the entire machine to a height
>>of four inches above the bench, and let go"
>
> The GPO Pulse & Bar generator had, in the manual, a sentence which said
> "It is quite possible that every component will test within spec but the
> equipment fail to work."
>
> And no further advice.
>
> Mike
> --
> M.J.Powell
Are they saying that there might just be some tolerancing problems in the
design? The sort of problem you get is if this circuit is at the fast end
of its spec, that one is at the slow end and this resistance is a bit high
then X fails to happen. Very difficult to anticipate all the most unlikely
situations and avoid them with complex systems.
"Robert Marshall" <spam@chezmarshall.freeserve.co.uk> wrote in message
news:m1abwfnjil.fsf@chezmarshall.freeserve.co.uk.. .
> On Tue, 8 May 2007, News Reader wrote:
>
>>
>> "Dr Teeth" <no.email.here.please@tardis.com> wrote in message
>> news:1ln143d7ja4tjsrgc2v3ihn1dbbot4fr06@4ax.com...
>>>I was just thinking how wonderful life was, when "News Reader"
>>> <no@email.invalid> opened his gob and said:
>>>
>>>>Can I get peoples opinions on and suggestions of lay / informal
>>>>remedies to intermittent faults.
>>>
>>> Bang your head against the wall and stick your tongue in a mains
>>> socket until the problem does not recur, or becomes permanent (i.e.
>>> non-intermittent).
>>>
>>
>> Hmmm.... not sure if I have totally got this one understood
>> correctly... but it sounds good :)
>>
>>
>
> It may sound good, but it will taste out of this world
>
> Robert
> --
> La grenouille songe..dans son château d'eau
> Links and things http://rmstar.blogspot.com/
In message <MrBs4sJIzXQGFwxU@nospam.net>, ian <ian@nospam.net> writes
>In message <HKChsCDRPGQGFwir@pickmere.demon.co.uk>, M. J. Powell
><mike@pickmere.demon.co.uk> writes
>
>>If you replaced faulty equipment then the new equipment showed the
>>same fault and the old gear was perfectly serviceable.
>>
>
>I had an old electric drill once. It started to become intermittent. I
>took it to pieces, checked the mains lead, but couldn't find anything
>wrong. But still the fault persisted, so I bought a new drill.
>
>The new drill exhibited exactly the same intermittent operation. I then
>decided to look at the mains extension cable ....:-))
In message <XLGdnajKupVhFtzbnZ2dnUVZ8vqdnZ2d@bt.com>, Phil B
<phil.remove.brady@hotmail.co.uk> writes
>
>"M. J. Powell" <mike@pickmere.demon.co.uk> wrote in message
>news:BQkAKrHIDNQGFwS6@pickmere.demon.co.uk...
>> In message <f1q2vt$sv6$1@news.datemas.de>, Graham <me@privacy.com> writes
>>>
>>>"News Reader" <no@email.invalid> wrote in message
>>>news:f1onnt$q80$1@inews.gazeta.pl...
>>>>
>>>> Hi,
>>>>
>>>> Can I get peoples opinions on and suggestions of lay / informal remedies
>>>> to intermittent faults.
>>>>
>>>> My /one suggestion is "bouncing", such as with a soft surface - e.g. a
>>>> bed. "Grasp device at one end, 'bounce' onto and off soft surface. Plug
>>>> in
>>>> and try again".
>>>>
>>>
>>>In the early '90s we were supplying BBC model B's to Pharmacies.
>>>The PSU suffered from dry-joints and the official trouble-shooting
>>>guide said something like this.
>>>
>>>"If the computer fails to start up, lift up the entire machine to a height
>>>of four inches above the bench, and let go"
>>
>> The GPO Pulse & Bar generator had, in the manual, a sentence which said
>> "It is quite possible that every component will test within spec but the
>> equipment fail to work."
>>
>> And no further advice.
>>
>> Mike
>> --
>> M.J.Powell
>
>Are they saying that there might just be some tolerancing problems in the
>design? The sort of problem you get is if this circuit is at the fast end
>of its spec, that one is at the slow end and this resistance is a bit high
>then X fails to happen. Very difficult to anticipate all the most unlikely
>situations and avoid them with complex systems.
Well, it was a 405-line P & B Generator, hardly cutting edge technology
in those days, 1958.
On Thu, 10 May 2007 23:05:34 +0100, M. J. Powell wrote:
> In message <MrBs4sJIzXQGFwxU@nospam.net>, ian <ian@nospam.net> writes
>>In message <HKChsCDRPGQGFwir@pickmere.demon.co.uk>, M. J. Powell
>><mike@pickmere.demon.co.uk> writes
>>
>>>If you replaced faulty equipment then the new equipment showed the
>>>same fault and the old gear was perfectly serviceable.
>>>
>>
>>I had an old electric drill once. It started to become intermittent. I
>>took it to pieces, checked the mains lead, but couldn't find anything
>>wrong. But still the fault persisted, so I bought a new drill.
>>
>>The new drill exhibited exactly the same intermittent operation. I then
>>decided to look at the mains extension cable ....:-))
>
> HeHe!
>
Basic rule: check the fuel before stripping the engine!
--
Peter.
If you can do it today, you didn't put off enough yesterday.
>
> All those are good.
> I worked in a mainframe design lab in the 1960s using TTL and wrapped
> backplane joints. Other techniques we used were:
> - look for dry joints - any not shiny and with a dusty appearance - and
> resolder them.
> - wiggle all the wrapped wiring with a stiff brush,
> - alter the supply voltage (but within limits). TTL had a tolerance of
> 4.75 to 5.25 volts but I liked to weed out anything which failed if I took
> it down to 4.3 volts.
> - flex or twist the printed circuit boards slightly - a real killer for
> intermittents but take care of high voltages and static sensitive stuff.
> - rattle all the boards. After visiting and fixing one troublesome
> system my boss asked me whether I'd rattled the boards. I had, with a
> plastic connector cover, but I was reprimanded for not using a hammer.
> On a subsequent occasion I was again reprimanded for not physically
> breaking any boards with the said hammer!!
> Not sure that's particularly good if you want to rely on a warranty
> though.
>
> Hope that helps.
>
> Phil
>
I found once or twice that replacing the board that was glowing worked
wonders. Another time, removing a dozen or so paper clips, which had been
fired around the room from lazzy bands, by the bored operators, also seemed
to help. Or, reducing the height of the flood water.
Intermittent Faults - Preferred Lay Remedies 
Linear Mode
