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Data General Nova 3

R

retrolimber

Member
Joined
Jul 1, 2018
Messages
14
Location
Venice
Hi there from Italy! I've recently purchased a Data General Nova 3 which has seen better days.
The front panel is in bad condition, as it is missing one yellow plastic bat handle switch and almost all the light bulbs.
I did some tests on one light bulb that survived and was not burnt out. I've desoldered it and applied 5V to it to get a very dim light.
I've increased the voltage up to 12V and the rice lamp lit up well. Now I suppose that 5mm 12V rice shaped light bulbs should be good
as replacement for the original ones. At the moment I have no way to test the front panel to check the voltage out of each light indicator on the PCB
so I'm asking if 12V 5mm light bulbs will work as replacements.
The thing that struggles me the most is the missing plastic "bat handle", as I'd like to display the Nova 3 and I hope to complete it with an original part.
Do you have an original spare part? I found a picture of the Vintage Computer Festival 2016 where some Nova's front panels were on display and the one from a Nova 3
was missing several switches. I don't know the name of the guy who had them but if you can put me in touch with him I will be very grateful.
Many thanks in advance,
Alessandro
 
Hi,
thanks for the reply. 12V lamps seem not to be properly working. Now I'm curious to do some tests with higher voltage lamps (maybe 24V lamps).
The LED mod seems to work fine, but I'd prefer incandescence lamps to keep it as original as possible.
I'm still looking for the yellow plastic bat handle. If somebody has one feel free to reach out by PM.
Thanks
Alessandro
 
The Nova-line generally uses either 24v or 28v bulbs depending on model.
https://www.foxdata.se/blog/tag/nova-312/ apparently successfully used the Hudson 2187D (as specified for the original Nova) in their Nova 3/12.

Voltage: 28V, 28 Volt Volts
Amperage: .04A, 40mA
Filament: C-2F
Maximum Overall Length: .52"/13.2mm, Excluding Leads
Maximum Overall Diameter: .23"/5.9mm
Average Rated Life: 10,000 Hours
Bulb: T-1 3/4, T1.75, Clear Glass
Base: WL Wire Terminal Leads

Your local Mouser stocks them: https://www.mouser.it/ProductDetail/VCC/2187?qs=qp111mKzDjgelZXllf1Wrw==
0,714 € each in quantity 10+.
These folks have them less expensively: https://www.replacementlightbulbs.com/lamp2187.html
0,30 € each in quantity 10+. International shipping appears to be possible

Although +Vlamp for the Nova 3 is specified as 13-15V the lamps are presumably under-driven in order to improve life expectancy. Note that the circuit design includes a 1k ohm keep-alive resistor to ensure that the filament doesn't cool completely when displaying a "zero" thus reducing the thermal shock that significantly affects bulb life. The original Nova didn't include a keep-alive resistor, but the subsequent models did.

Alternatively the Hudson 2176D is the 24V bulb specified for the Nova 800 &1200 which used the same driver circuit as the Nova 3, but I'm uncertain whether the +Vlamp voltages are quite the same. The 2176D can be found but is more expensive.

The page on gunkies (https://gunkies.org/wiki/Data_General_Nova_3) is incorrect regarding the actual drive voltage since the front panel schematic shows a 6.8uF 20V electrolytic between VLAMP and GNDLAMP.
 
Last edited:
Many thanks for the detailed information!
I've placed an order for the lamps: as soon as I get them installed in the Nova I will post updates here.
Thanks again,
Alessandro
 
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