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Author Topic: replacement light bulb for pilot light on a Neumann N52a power supply?  (Read 5811 times)

brucekaphan

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Thanks Klaus! If this lead doesn't pan out, then it appears that panman has a manageable alternative.
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usattler

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  • Real Full Name: Uwe Sattler

Bulb #2821 is the 4V/0.25mA version, NOT the 12V type! Make sure you find the 12V bulb, since the 4V type 2821 will immediately blow if connected to the 11.5Vac transformer secondary.
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Uwe Sattler
Technical Director - Neumann|USA (retired)

panman

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I just ordered these lamps: https://www.banzaimusic.com/Bulb-12V-20mA.html.
You can replace the broken lamp with this. First you need to solder off the contacts and then you can remove the lamp from the base using vinegar to dissolve the glue. Be carefull, because the base cracks easily. It should be easier, if the glas is not broken. I`ll report back, when I have got the lamps.

We can forget that! I received the lamps. Transplanted one into a cleaned base and tested with a V72. Could not see any light on the front-plate spot, where the light should shine through. The lamp works, but there is only a tiny glimmer of a glow :(. What we are looking for is a lamp with 1 w, but there was not enough info on the link. 
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Esa Tervala

brucekaphan

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Thanks panman, for letting us know.
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panman

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We can forget that! I received the lamps. Transplanted one into a cleaned base and tested with a V72. Could not see any light on the front-plate spot, where the light should shine through. The lamp works, but there is only a tiny glimmer of a glow :(. What we are looking for is a lamp with 1 w, but there was not enough info on the link.

You must excuse me for beeing too hasty! Yes, it does not work on V72, because the voltage(c. 6.3V when correct) is too low. Then I remembered that the secondary of a N52a(t) is 11.5V and I just tried it and it works perfectly on one of my N52:s. Comparing another N52 (with the orig. Rafi in it)with this shows no difference in brightness at all.
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Esa Tervala

brucekaphan

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I'm deeply impressed with and grateful for the persistance, knowledge and expertise at this blog!
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klaus

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I have found a supplier of original RAFI bulbs in 12V:
http://illi.eu/listen/Miniaturlampen.pdf
info@illi.eu
The socket type is specified as "R0728 F9 (f. Rafi R2821)"
and the part number is: 0901212.
Price: €5.40

I have contacted them for technical info and quantities smaller than 100 pieces
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

brucekaphan

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That's some super sleuthing there Klaus! Thanks!!!
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panman

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and the part number is: 0901212.

This one is 12V 120mA, shouldn`t it be 12V 20mA? There is no such on the list. 120mA might affect the filament voltage too  much or not?
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Esa Tervala

klaus

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Good point. A concern is that the 120mA bulb rating maybe too dim and/or draw too much current for a transformer designer for a 100mA tube heater current draw. I am waiting to hear from the company to take this to the next step.

Uwe?
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

klaus

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Illi in can sell 10 of them @ €8.50 each + shipping.
But the discrepancy in wattage needs to be solved first.
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

brucekaphan

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Thanks once more Klaus, for your persistence. I can imagine wanting at least a few for backup, anyone else out there interested in splitting the purchase, in the event that its specs will be found to be within tolerance?
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