12 May
2014
12 May
'14
10:49 a.m.
I picked up a little old Tandy 1650 chess game this morning. Batteries are
still in it, of course, corroded to heck and back again - but thankfully
the PCB seems unharmed.
The lower half of the case shell is just the battery compartment and one of
those disc-type piezo buzzers, with lugs on the case melted to hold the
buzzer in place. After treating the battery terminals, can I dunk the case
half - buzzer and all - in water? I'm not sure if those buzzers are sealed
units or if water will end up where it shouldn't be and cause damage.
cheers
Jules
12 May
12 May
12:45 p.m.
Far as I know, those piezo transducers are essentially solid-state devices.
I wouldn't boil one for an extended period, but I can't see a clean,
hot-water rinse harming anything.
Like most electronics, once you're done, just stick it in an oven with a
pilot lamp, or some similar environment.. and let it desiccate for a day
after.
On Mon, May 12, 2014 at 12:49 PM, Jules Richardson <
jules.richardson99 at gmail.com> wrote:
I picked up a little old Tandy 1650 chess game this morning. Batteries are
still in it, of course, corroded to heck and back again - but thankfully
the PCB seems unharmed.
The lower half of the case shell is just the battery compartment and one
of those disc-type piezo buzzers, with lugs on the case melted to hold the
buzzer in place. After treating the battery terminals, can I dunk the case
half - buzzer and all - in water? I'm not sure if those buzzers are sealed
units or if water will end up where it shouldn't be and cause damage.
cheers
Jules
2:59 p.m.
I picked up a little old Tandy 1650 chess game this morning. Batteries are
still in it, of course, corroded to heck and back again - but thankfully
the PCB seems unharmed.
The lower half of the case shell is just the battery compartment and one of
those disc-type piezo buzzers, with lugs on the case melted to hold the
buzzer in place. After treating the battery terminals, can I dunk the case
half - buzzer and all - in water? I'm not sure if those buzzers are sealed
units or if water will end up where it shouldn't be and cause damage.
The actuall buzzer element (note, I've seen it called a 'bender' in at
least one manual...) is a metal disk with the piezo crytal (circular) on
one side wit h a metal film ptaed onto it. I don't think the crystals
used in modern piezo buzzers are damaged by water (the crystals used in
some older record player cartridges _were_ affected by high humidity).
In some cases this disk is fitted into a plstic hosuing, which has an
obvious hole to let the sound out. Those housigns ae clearly nt
waterprrof anf watre is likely to stay inside them. Not a good idea.
In the case of the bare disk, I would be worried about water getting
trapped between the disk and the unit's case and causing problems later.
-tony
3:40 p.m.
On 05/12/2014 04:59 PM, Tony Duell wrote:
In the case of the bare disk, I would be worried about
water getting
trapped between the disk and the unit's case and causing problems later.
Yes, good point. I did do some googling in the end (should have done that
first!) and some manufacturers seem to state that theirs are not waterproof
(perhaps the problem is with whatever is used to bond the plate to the
disc) - with that in mind, I ended up being careful not to get this one
wet, just in case. Thankfully the buzzer was at the other end of the case
(more or less) to the battery compartment.
All *seems* to be well now, other than the -ve wire from the battery
compartment needing replacing; the system powers up and seems to "work" - I
just need to remind myself how to play chess :-)
cheers
Jules
9:31 p.m.
On 5/12/2014 3:40 PM, Jules Richardson wrote:
On 05/12/2014 04:59 PM, Tony Duell wrote:
Most of the devices I have seen have seals on them that are designed to
keep out cleaning fluids. The micro units almost are even shown in sale
literature with seals on them. I recall the larger ones were sealed on
top, not sure about the bottom, but I believe they must have been water
or solvent proof from the bottom.
Jim
In the case of the bare disk, I would be worried
about water getting
trapped between the disk and the unit's case and causing problems later.
Yes, good point. I did do some googling in the end (should have done
that first!) and some manufacturers seem to state that theirs are not
waterproof (perhaps the problem is with whatever is used to bond the
plate to the disc) - with that in mind, I ended up being careful not
to get this one wet, just in case. Thankfully the buzzer was at the
other end of the case (more or less) to the battery compartment.
All *seems* to be well now, other than the -ve wire from the battery
compartment needing replacing; the system powers up and seems to
"work" - I just need to remind myself how to play chess :-)
cheers
Jules
13 May
13 May
10:54 a.m.
Most of the devices I have seen have seals on them
that are designed to
keep out cleaning fluids. The micro units almost are even shown in sale
A number of electromechanicla devices (swithces, piezo buzzers, relays,
etc) have tape seeals fitted at the factory. They can then be soldered ot
a pCB, the PCB washed in the normal flux-removign solvents, and then the
teals ripped off. But after the sals have been remvoed, the devices
should probavbly not be immersed in solvent.
-tony
2:36 p.m.
On 5/13/2014 11:54 AM, Tony Duell wrote:
Use a BEE. They will buzz even when wet.
What do you do if you require a weather resistant buzzer?
Ben.
Most of the
devices I have seen have seals on them that are designed to
keep out cleaning fluids. The micro units almost are even shown in sale
A number of electromechanicla devices (swithces, piezo buzzers, relays,
etc) have tape seeals fitted at the factory. They can then be soldered ot
a pCB, the PCB washed in the normal flux-removign solvents, and then the
teals ripped off. But after the sals have been remvoed, the devices
should probavbly not be immersed in solvent.
-tony
13 May
13 May
10:34 a.m.
All *seems* to be well now, other than the -ve wire
from the battery
compartment needing replacing; the system powers up and seems to "work" - I
It is not uncommon for the electorlyte fro ma leaking battery to creep
along inside the insulatio nfo one of the wires and corrode the wire
strands themselves. This can obviously cause an open-circuit, it can also
cause nasty intermittant faults.
It happens on cars too, the battery wires then gain resistnace so things
go wrong when the starter motor is used (t draws around 600A after all).
That can be 'intersting' to trace if you are not expecting it.
-tony
3:45 p.m.
"It is not uncommon for the electrolyte fro ma leaking battery to creep
along inside the insulation of one of the wires and corrode the wire
strands themselves. This can obviously cause an open-circuit, it can also
cause nasty intermittent faults."
This is what's known as "Black Wire Syndrome".. you may encounter it in a
variety of devices, but in my experience it's most commonly associated with
leaking Ni-Cad batteries.
The battery wiring looks OK from the outside, but the black wire is
completely corroded out inside the insulation jacket. There may still be
some electrical conductivity, but you'll never be able to reliably solder
or crimp onto the wire again.
Comes up when you're replacing internal rechargeable batteries in various
old gear. Had a case of it here, a couple months ago - in this instance, it
was the battery pack in an Epson PX-8 CP/M portable machine.
As an aside - for what it's worth, man oh man do those recent-generation
Ni-Cad batteries have some capacity! Every vintage unit I rebuild with new
cells will run for at least twice as long as the original spec. I think
this PX-8 goes for like 18-20 hrs at this time. Guess that's what you
expect, when a 3300 mA/h part drops-in for a 1200 or 1600 mA/h original!
On Tue, May 13, 2014 at 12:34 PM, Tony Duell <ard at p850ug1.demon.co.uk>wrote:
All *seems* to
be well now, other than the -ve wire from the battery
compartment needing replacing; the system powers up and seems to "work"
- I
It is not uncommon for the electorlyte fro ma leaking battery to creep
along inside the insulatio nfo one of the wires and corrode the wire
strands themselves. This can obviously cause an open-circuit, it can also
cause nasty intermittant faults.
It happens on cars too, the battery wires then gain resistnace so things
go wrong when the starter motor is used (t draws around 600A after all).
That can be 'intersting' to trace if you are not expecting it.
-tony
14 May
14 May
1:11 p.m.
This is what's known as "Black Wire
Syndrome".. you may encounter it in a
variety of devices, but in my experience it's most commonly associated with
leaking Ni-Cad batteries.
It's quite common in older cameras using mercury cells for the exposure
meter too. And a right pain it is... You often have to stirp half the
cmaera down to replace the wire.
The battery wiring looks OK from the outside, but the black wire is
completely corroded out inside the insulation jacket. There may still be
some electrical conductivity, but you'll never be able to reliably solder
or crimp onto the wire again.
I nearly always replce all wires associated with leaky battery packs for
this reason. Even if they look OK and test OK...
Comes up when you're replacing internal rechargeable batteries in various
old gear. Had a case of it here, a couple months ago - in this instance, it
was the battery pack in an Epson PX-8 CP/M portable machine.
When I did my PX8 a few eyars ago I found the connectors used to connect
the battery to the main PCB were stilleasily available. So I replaed the
lot. I also made u pa cable to link the PCB to my bench supply (in place
of the battery) so I could run the machien 'for ever' without having to
worry about havign a flat battery pack.
-tony
13 May
13 May
12:55 p.m.
They might not be but their big brothers the SONAR T/R units use?piezoelectric crystals in
contact with water.
Rod
________________________________
From: Jules Richardson <jules.richardson99 at gmail.com>
To: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
Sent: Monday, 12 May 2014, 23:40
Subject: Re: Are piezoelectric disc-type buzzers waterproof?
On 05/12/2014 04:59 PM, Tony Duell wrote:
In the case of the bare disk, I would be worried about
water getting
trapped between the disk and the unit's case and causing problems later.
Yes, good point. I did do some googling in the end (should have done that first!) and some
manufacturers seem to state that theirs are not waterproof (perhaps the problem is with
whatever is used to bond the plate to the disc) - with that in mind, I ended up being
careful not to get this one wet, just in case. Thankfully the buzzer was at the other end
of the case (more or less) to the battery compartment.
All *seems* to be well now, other than the -ve wire from the battery compartment needing
replacing; the system powers up and seems to "work" - I just need to remind
myself how to play chess :-)
cheers
Jules
14 May
14 May
1:04 p.m.
They might not be but their big brothers the SONAR T/R
units use=A0piezoele=
ctric crystals in contact with water.=0A=
I guess this can be repeated here...
An old trick for waterproofing nroaml transducers (audio and ultrasonic,
including microphoes) is to put a thin rubber membrane over the business
end. Such membranes are sold (for a rather different purpose) in most
pharmacies....
The story goes that the new guy in a research group was sent down to the
local pharmacy to buy a large number of boxes of condoms. Said guy then
asked for a receipt 'so I can claim on expenzss'. 'You can claim _those_
on expenses ?!? Where ever do you work?'
-tony
3880
days inactive
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