HeathKit IG-1272

Hi All: I have a Heathkit IG-1272 that uses 3 incandescent lamps in the feedback loop of the oscillator. One of the lamps has a broken lead and needs replaced. Does anyone know what type lamp this is? It's bigger than a "grain of wheat" lamp. More like a "grain of corn" Or better yet anyone have a manual on this?

Thanks RonL

Reply to
<r.laury
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There's one on eBay. Perhaps the seller has the manual.

Bob

Reply to
BobW

** Good bet all three are the same.

Why don't you test the other two and see what voltage and current lightes them up brightly.

Then you know the ratings you want.

Incandescent ( tungsten) lamps with of the same rating behave very similarly.

..... Phil

Reply to
Phil Allison

wrote in news:sKadnbctJKIsQW_anZ2dnUVZ snipped-for-privacy@comcast.com:

I'm looking at my manual and...nothing. Just identified as a tungsten filament lamp and a Heathkit part number. No voltages given on the schematic or in the circuit description.

Try measuring the resistance of one of the surviving lamps. Since these barely glow, if at all, current has to be very low and I'd make a wild guess that they're rated for a fairly low voltage.

The Mouser catalog lists some potential (sorry!) candidates by Chicago Miniature:

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--Damon

Reply to
Damon Hill

"Damon Hill"

** Three of their 28 volt, 24mA lamps ( in series) would be very close to the mark.

Best buy half a dozen and match them for dull red brightness when in the unit.

...... Phil

Reply to
Phil Allison

Thanks all. That's what I did. They seem to be 12V @ 40 mA.

Reply to
<r.laury

With some luck you might find spare bulbs for Christmas light strings that match or can be combined. But don't just pluck them out of the strings in your garage or the missus will be rather grumpy towards the end of the year ("Ron, I can't believe you did this!") ...

Nice thing about those is that you can carefully straighten the leads, slip off the plastic piece and then solder them in.

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

Hi Group Whew! I found them here:

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I've only got about 5 hours searching in this so far. But it's worth it. Thanks to all for the help.

RonL

Reply to
<r.laury

Thanks for the link, Ron, bookmarked it right away. Lightbulbs are also excellent devices to make RF noise sources with.

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

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