reed switch replacement for PULSAR

[CompuChron2]

Hi,
will that fit on a pulsar?
http://cgi.ebay.fr/50-pcs-new-reed-switch-magnetic-sensors_W0QQitemZ7581836197QQcategoryZ58169QQrdZ1QQcmdZViewItem
or this?
http://cgi.ebay.fr/Latching-Reed-Switch_W0QQitemZ6029375666QQcategoryZ11644QQrdZ1QQcmdZViewItem
where can i get a new reed switch??

thanks

[Diginut]

I am sure some of the Pulsar People on DWF can advise where to get the most suitable reeds.

I know from other exprience, that RS components/UK sell a range of minature reeds. The smallest being about 6mm long, and 1.5mm diameter. Having never replaced one in a Pulsar I dont know for sure whats needed, but this certainly sounds pretty small !

[bruce wegmann]

Neither of these is a workable replacement for the original Pulsar reed switch. One is too large, the other has an unnecessary latching function [it does not automatically return to the "off" position when the magnetic field is removed; it requires a second field application to do so...in other words, you would have to press the button a second time to switch it off]. The only real suitable replacements are switches removed from TC modules [it is a sad fact that there is no shortage of non-working ones out there]; in addition to being dimensionally and functionally correct, they are also designed to respond to the specific magnetic field strength of the pusher magnets [this factor alone makes it a virtual certainty that none of the ones you suggest would work]. Unfortunately, there are no short-cuts to doing good Pulsar repairs. The company that made the original switches is still in business, but the specifications for the Pulsar switches are different from the standard model. They were willing to custom-make some on special-order, but the minimum order is not small [per switch type; and there are four of them in total...demand and setting switches are not interchangeable, and P3 and P4 switches are very different sizes]. If some of you serious collectors want to PM me with your needs, maybe cumulatively we could meet the minimum requirements, and start putting new switches in our watches, instead of salvaged ones [I would consider that this in no way would compromise the originality of the watch, as they are from the original source, and considering the improvements is manufacturing technology over the last thirty years, these are probably much more reliable than the vintage ones].

[Diginut]

I totally agree with your desire to keep modules original, and use the correct parts.

But 30 yrs on and this becomes a restoration business using the best compatible parts available, especially if there?s no longer any original stocks or suppliers.

I would rather get a module working than have a dead module, but would also like to preserve a donor module unless it was a hopeless case at which point I might salvage what I could !

As for the reeds I referred too, I?ve just had a look at a pulsar module I have to hand. The most accessible reed on it measures approx 5mm long and 1.5mm wide. With a simple make or break action using a tiny amount of force from the pulsar button magnet in the pusher. How much force is impossible to quantify here.

The one I was referring too above are also 5.3mm long, and 1.4 mm in diameter, looks the same in constructional terms, and operates identically as far as I can see. The only issue to my mind is whether the tiny amount of magnetic force required is way out or similar. I suspect similar. The company that makes them has been around since the 60?s and may even be the same one as Pulsar used, but I don?t know who the original supplier was as that really is getting a bit anal.

So, if it?s the same size, same spec, works the same, looks the same, does the same job, and its totally hidden from view, was repaired with great care, and got my cherished watch functioning again, what?s wrong with this idea ?!

(I admit I haven?t swallowed one, so I don?t know if they taste the same. But I suspect they do :)

[CompuChron2]

Are you talking about these ones:
http://www.maplin.co.uk/Module.aspx?ModuleNo=44110&&source=14&doy=17m1

Will they fit?

[Diginut]

The reed I was referring to is made by Crydom, offices in USA and UK. Parts available from RS, Farnell, and maybe Crydom themselves if you ring up and ask for experimental samples.

www.Crydom.com or (.co.uk) are the supplier I was referring too.

The only likely candidate is Crydom VDA200GH, approx ?2 each, as shown rightmost in this table :-

http://www.crydom.co.uk/Webpages/sub_and_tiny.htm

http://www.crydom.co.uk/Webpages/reed_s ... _notes.htm

http://www.crydom.co.uk/Webpages/reed_o ... agnets.htm


The magnetic sensitivity / strength / distance is the all important point about this switch, as I believe everything else about makes it the best and only likely replacement part. But it?s also the one point that needs experimenting with. This could be done outside a module, using a pulsar button with the magnetic still within it, and moving it back and forth from 2mm to 8mm from the reed and work out where it closes, and releases again.

As with all things there are ways of expressing the reeds operational performance, and looking at tables of data (as shown in the above links). EG, a reeds sensitivity for closing/opening is rated in ampere-turns (nice and obscure standard), and the distances in MM depends on the magnetic flux rating and shape/orientation of the activating magnet as measured in Micro Webers (even more unfamiliar, but a standard none the less). And using these two ratings and some look up tables it is possible to work out if a reed / magnet is a likely combination. But the one thing I don?t know is the magnetic rating of the magnets used in pulsar buttons. However, anything 3mm long is likely to be similar to currently available 3mm long sub miniature magnets available today. Etc.

But this is all getting a bit OTT for DWF, and in the time I?ve spent writing this I could have ordered one on-line and let you know how the experiment goes within 48 hrs !

The particular reed I mention is the tiniest one they do, needing the smallest amount of magnetic force to activate and release. My gut feeling is that this will do, but to prove the point I need to actually try it out. If it isn?t the one, and you don?t have a dead module with good original reeds, then give up as there are no other modern alternatives !


Off course, I could be wasting my breath, because I bet I know one person who occasionally lurks on the forum who?s been quietly replacing reeds in modules for years, doing an neat excellent and perfect job each time, and making a good income from doing it, and who probably just gets on with it rather than arguing about if it?s the precise absolute 1973 original reed, and couldn?t give a stuff what anyone on here says, because hes been successfully doing it for years !


Heres a pic of pulsar module with 5mm reed :-



And heres a screen grab of the crydom one I would try (but out of stock today !) :-

[bruce wegmann]

This all does seem to be getting overly complicated; I am still inclined to the opinion that the most straightforeward approach is to use a switch salvaged from a non-working module [as much as it pains me to say it...there is no shortage of those out there]. On the other hand, if one simply must have a new replacement, I can tell you that the original manufacturer [who supplied every reed switch Time Computer ever used] is still in business, and willing to do a custom short-run of any type [there were four, if you count both setting and demand switches for P3 and P4 models]. If there is enough interest, I might bite the bullet and order some up [I did talk them out of a few "engineering samples", and I can say with authority, they are beautifully made, function flawlessly, and maintain the original look of the module, as well]. PM me if you're interested...

[azimuth_pl]

I've had no problems with using modern switches which give the same result. If the magnetism is too strong then you only have to move the reed slightly away from the button or closer if the magnet is weak.
I don't see the point in paying more for reeds just because it's the same manufacturer who produced them for Pulsars. It's the functionality that counts - not the label. Would you consider a Pulsar to be original ONLY if it would be using for instance Rayovac batteries - just because these were added to the watches sold in the 70's.

[CompuChron2]

So Azimuth,
where do you get your reeds?
Olivier

[azimuth_pl]

at a local well-supplied electronics store or every weekend at the electronics market. many types are available but the small ones that I find most appropriate are becoming low in supply.
however internet must be the best source but I didn't bother so far as shipping would exceed the value of a few reeds by 1000%.

[bruce wegmann]

Gentlemen, let's hold up a moment here, please! Consider; do we, as collectors and aficianados of the Pulsar watch, respect the design and integrity of these timepieces, or not? If we are trending to the notion that ANY part that "works", is acceptable, than I have to register, in the strongest possible terms, my objection to that idea. I do so on four fronts, namely; perfectly servicible switches are easily salvaged from non-working modules [of which, unfortunately, there is no shortage], acceptable OEM replacements are available from current manufacture, and in either case, we are not talking about an overly expensive part, or any additional complication in the repair [to do it RIGHT!], so I am not readily willing to accept any excuse for not doing so. Finally, and I say this in all seriousness, future collectors will decry such incompetance and debasement. It requires no stretch of the imagination to see future Pulsars offered as "excellent overall condition, but has been repaired, and contains non-original parts"; therefore such improvisation is ultimately undesirable and counterproductive. To those who would label me as a hard-line purist, I reply: "GUILTY AS CHARGED"!. I personally do not want to open up a thousand [or more] -dollar watch and find some bodged-up repair has been done [and it has already happened; I hated it!]. There is more to collecting than mere ownership or possession; I think we have, as a group, a duty to the future, to preserve and protect the objects of our collecting passion. We will not be here forever; at best, we have only tempory guardianship over the things we "possess", and others will ultimately "own" them [like it or not, you really can't take it with you]. I intend to pass my collection on in as nearly pristine condition as possible...how about you guys...?
Final note; I hereby undertake, if sufficient interest is expressed to me, to personally shoulder the financial burden and custom-order the modern setting switches. Further, I will make them available at cost [plus postage, of course]. I can do no more...
Oh. and as to the battery analogy; fatally flawed and invalid. A battery is not a "part" of a watch in the same sense that a chip, or display, or a case [or a switch!] is. Batteries come and go, and those from different manufacturers work equally well [partly because they are held to strict tolerances of voltage and size], but all the Time Computer switches came from a single source, and there is thus only one acceptable replacement.

[azimuth_pl]

Your right but that just came to mind. But when restoration is the subject you have to use the parts available or produce them on your own just like in vintage cars where parts are not available. If the reed looks the same and gives the same effect then why not? I get your point but costs count as well in restoration. I get these for a few cents each and my watches work. Shipping them from the other part of the Globe would not be cost-effective.

[CompuChron2]

Hi guys,
I understand you point of view Bruce , it's important to get the original part when restoring to "mint condition" or restoring a massive gold watch, but in my case , I have an old P2 which is in medium cosmetic condition , it has a big scratch on the case ,the glass is rather poor too,but it only needs a reed switch to work properly.
It will be a very nice watch to wear daily , I have no dead module to take the switch from so I thought the easiest way to make it work was finding a good replacement part.
But as there is just few $$ difference between a new reed which may work or not and a used one which will work, I think I'll go for the second solution....

Olivier

[CompuChron2]

Hi,
I finally ordered a dead module from Barbie9 (mike barbero) with some other parts (magnet , link,screws) which I received this morning.
I trained on one of the 2 reed switch of the dead module trying to take it a part first attempt : broke! this stuff is fragile!
The second reed switch was removed more carefully with my soldering iron(I have to say that I have no experience at all in soldering),and this time the switch was save.End of part One.
Now I have to take out my faulty reed switch from my working module, no second chance this time , it has to be good at first try....and it is,oufff!
end of part 2
Now I have to put my working reed switch in my working module, takes me 1 mn as the switch fits easily in place just to tiny points of soldering and there it is!I don't want to loose time to try to testthis , I put the watch back in place and bang it works at first time!It sets correctly , runs ok , it looks to me that I have a working P2 now!!!
:D :P

I just wanted to say that the operation is rather easy and can be made by anyone!

Good night and thanks to all of you for your advices

[Seer Taak]

A working P2, with all original parts. The Pulsar purists would be proud of you. Hope you have many happy hours with your watch :)