SCR datasheet or equivalant

Discussion in 'General Electronics Chat' started by enduro250z, Aug 22, 2010.

  1. enduro250z

    Thread Starter Member

    Jul 6, 2010
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    I have been trying to find a data sheet for the following components and cant find one anywhere afer many many hours of searching!. Has anyone got one of those 'Phillips ECG cross reference book' and find any data on these?

    they are a TO-92 case component (3 legs) I believe they are a SCR thyristor.

    the brand is Toshiba and they originate from devices from the late 70's to early 80's


    FOR2B 9.L
    FOR2B 9.A
    FOR2B 4.H

    Thanks for your help
     
    Last edited: Aug 22, 2010
  2. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Do you have the parts available to make a picture of them?
    If so can you post the pictures here?

    Bertus
     
  3. enduro250z

    Thread Starter Member

    Jul 6, 2010
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    Yes i can do that. Im sure its some sort of SCR. Dont ask what that other TO-202 case item is because i cant id that either. All i can read is 'SC' and maybe 998 at a guess. Im hopping to get another one of these to de-pot another way, perhaps boiling in water because this has been a nightmare. The epoxy is extremely hard to remove. Many components i cant ID but one of the lucky ones was the FOR2B that i can actually read the code.

    [​IMG]
     
    Last edited: Aug 22, 2010
  4. SgtWookie

    Expert

    Jul 17, 2007
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    Searching for FOR2B on NTEINC.com's site gives these as a possible match:
    http://www.nteinc.com/specs/5400to5499/pdf/nte5400_06.pdf

    A wild guess tells me that yours might be rated for 200V or more.

    From the information in NTE's datasheet, select any sensitive SCR capable of 0.8A or more, and a voltage rating of 200v or more.

    NTE's site is handy for getting cross reference data, but the parts themselves are horrifically expensive compared to the originals, usually in the range of 3x to 10x as much.
     
  5. enduro250z

    Thread Starter Member

    Jul 6, 2010
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    Its in a CDI unit, so maybe 200V. I would really like to find the original specs first though to know the rating. I listed 3 above and they all had a different 2 digit code after them. What would this mean? is it just a batch number or something?.

    I have emailed Toshiba and hopefully they may have an answer. I did heaps of google searches but couldnt find the NTE site.

    If its a 0.8amp one, then i wonder if this would also be suitable? C103B

    Im surprised that i couldnt find a data sheet on it, but i guess they may have changed part numbers since the 80's

    It would be good to be able to buy it from an electronics supplier here in Australia though.

    Thanks so far!
     
  6. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Ignore the other numbers, theyre just date codes of manufature.

    If it's a CDI I'd get the highest voltage I could. Some operate around 120V, others go above 400V and you don't have a circuit.
     
  7. SgtWookie

    Expert

    Jul 17, 2007
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    It's hard to find parts in Aussieland because you blokes read the catalogs upside-down. ;)

    Using a higher voltage rating than required won't hurt. Going too low will result in smoke. :eek: Since it's a CDI, I'd up the V requirement to at least 400.

    The numbers could mean different things, such as batches or manufacturing year/days or the like, or it could also be referring to voltages. I suspect the former.

    A huge number of items that were available in the early 80's have been obsolete for many years. However, in this case, it should not be much of a challenge to locate an equivalent or better-than replacement part.

    For example, look at something in the Teccor EC103x series, EC114x, 2N6565, TCR22-6 or -8. Make sure the V rating is 400 or higher.
     
  8. enduro250z

    Thread Starter Member

    Jul 6, 2010
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    When ive been searching now it seems to be that the FOR2B is a 100V, thats the impression i got from the NTE site but to play it safe a higher voltage would be good.

    I will have the circuit properly worked out soon. The time has come when we need to start to make out own CDIs because they are getting really hard to find for these bikes and people ask over $100 US on ebay when they turn up and you could be sold a dud.

    So they are other part numbers i can try to get a FOR2B equivalant?

    One other question, when getting to this component, i found that it had a rubbery/plastic sleeve over it and the FOR2B case was completely sealed inside it with a white glue. Why would this be so? Was it to stop heat damage from the hot? resin or epoxy when it was poured in?
     
  9. SgtWookie

    Expert

    Jul 17, 2007
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    Yep, buying used stuff like that is a pig in a polk; you can't be certain what you'll get.

    Probably.
    I just gave you some examples. Honestly, I don't have the time to provide a complete cross-reference of every sensitive 0.8A SCR that was ever made.

    You're going to have to do some research on your end. I'm not certain what suppliers are available to you locally, or any idea what they may stock. Some names I've heard are RS Components, Farnell, perhaps Maplin, and others that I can't remember and I've never used. Since I'm practically on the other side of the planet, trying to access their websites is agonizingly slow, even with a fast DSL connection. There's a kazillion routers between me and them.

    I see that quite a bit on various boards. I can't give you a good answer offhand. It may be because the potting compound they used was not an ideal insulator.
     
  10. marshallf3

    Well-Known Member

    Jul 26, 2010
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    What kind of bike does it go on? We've had occasional CDI problems with our older Honda CX500 series for years and now that even spares are getting more scarce (thus more pricey) a company now mass produces a replacement that just requires 12V and the signals from the pulsar (timing) circuits.

    We've got full schematics and a parts list for our originals but nobody has bothered making a PC Board to build them on. Ours are a bit more complex, not because it's a twin but because of things like a built in rev limiter and the fact that around 5,000 RPM it switches to a higher voltage and advances the timing a bit.

    The more common ones aren't that hard to duplicate in most cases, I made one for an older Kawasaki dirt bike with some spare components. on most bikes the rotor generates the proper HV pulse so there's no voltage step up circuitry required, just a way to charge a cap and discharge it through the coil at the proper time with an SCR.
     
  11. enduro250z

    Thread Starter Member

    Jul 6, 2010
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    The bikes are 77-84 suzuki PE 175, 250 and 400. We have a worldwide owners group/club for these. Another guy has already disected a 79 model CDI and got 99% if not all components ID'd. He had it a lot easier though as the 79 175 model had a hard white 'marble/stone' type potting mix he could easily chip away. We eventually want to do all the models. These are not a model that the main dirt bike aftermarket ignition companies want to make CDI units for yet as they are a 'vintage bike'. Due to the set up of the stator and rotor magnet design, it is too hard/not possible just to fit an aftermarket universal ignition off something else as we dont have external pick up/trigger coils in hall effect style. The system is a magneto type (no battery) which uses specially designed magnets. The easiest and simple option is to just copy the OEM basic CDI unit.

    I used to be able to know how to make PCB's and im sure theres info on the net how to do it. If not we can always use universal grid PCB sheet. Ive seen it at www.jaycar.com.au and you join the square pads with solder. They are close enough to bridge. The main priority at the moment is to identify all our components and find modern equivalents and if possible improve on the design if we can.

    Is there a website or list available that can tell you all equivalent part numbers for a ECG/NTE part number?
     
    Last edited: Aug 22, 2010
  12. marshallf3

    Well-Known Member

    Jul 26, 2010
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    ECG is gone, but NTE must have a website somewhere as I still occasionally see their parts offered for sale on Mouser.

    For making PC Boards look into the "toner transfer method", alternately if you can get enough people interested and some backing you can get a run of 100 or so double sided boards professionally made for less than $500, sometimes even far less if they're having an intro sale.

    Plenty of free or close enough to it PCB design software out there too. I use DIP Trace but have the full license. They do offer a fully functional version for free but it's limited to 500 pins and two layers.
     
  13. SgtWookie

    Expert

    Jul 17, 2007
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    NTE's website is:
    http://www.nteinc.com

    Cross reference search engine:
    http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm

    It only crosses from competitor parts to NTE parts, of course.

    They bought out ECG, who bought out Sylvania (I still have a Sylvania IC or two).
     
  14. enduro250z

    Thread Starter Member

    Jul 6, 2010
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    Yeah ive seen the NTE site but it would be good to cross ref their numbers back to other brands. im looking around on ebay to see if theres any usefull old semiconductor books.

    Thanks for the PCB tips. We wont be at that stage for a fair while yet though.
     
  15. SgtWookie

    Expert

    Jul 17, 2007
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    It's not so much of a challenge anymore since the Internet really came into it's own, with manufacturers and vendors having parametric search engines. In the "old days", it was a real chore.

    NTE's search engine goes just one way by design. If it went both ways, they'd have a hard time selling anything; as their components are almost always far more expensive than can (or could) be obtained from other vendors.

    NTE is a vendor, not a manufacturer. When a manufacturer is about to discontinue an IC that's been in production for years, NTE might commission a run of parts marked with their own logo and part number; and then make a killing selling them when the OEM stocks run out.

    If you don't believe me, try looking up an LM3914N on various vendors' website for pricing info. Then search for it on NTE's website in their cross-reference engine, and then price out the NTE equivalent.

    Howard W. Sams used to publish an IC cross reference book, but it didn't include 3-legged critters like SCRs or transistors. I don't think they publish it anymore.

    ICMaster has a heck of a lot of parts in it; try there.

    http://www.icmaster.com/search/HomePageAction.ad
     
  16. enduro250z

    Thread Starter Member

    Jul 6, 2010
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    i signed up for the IC master website. It looks pretty good.
    Thanks
     
  17. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Yea, LM3914 is $6 via NTE but only $1.95 as the real part from Jameco.
     
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