25 Jul
2018
25 Jul
'18
5:42 p.m.
It might be worth saving the bases and buying "grain of wheat" lamps to rebuild
the lights. I see ~70ma 6v lamps available. That sounds similar to the original
specification.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Brent Hilpert via
cctalk <cctalk at classiccmp.org>
Sent: Wednesday, July 25, 2018 8:21:58 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: HP-2116 front panel lamps
On 2018-Jul-25, at 6:47 AM, Christian Corti via cctalk wrote:
On Wed, 25 Jul 2018, it was written
To mention, they are actually run below-spec in the processor, which of course improves
longevity and reduces the heat next to the plastic front panel.
Christian, when I was restoring the HP Computer
Museum's 2116A I ordered a
bunch of these 345 bulbs from 1000bulbs.com - but it seems they no longer
stock them.
I did find this listing though which looks current...
https://www.lighting-pros.com/eiko-345-t-1-3-4-midget-flanged-sx6s-case-of-1
0
They are around 0.04A current draw - not 0.75A!
Yes, the Installation and Maintenance Manual on bitsavers
(02116-9153_2116B_Vol2_Oct70.pdf) contains several errors.
Interesting enough, my printed copy of this manual from 1968 (that is completely
different from the 1970 one; it only has parts lists and schematics, the chapters for
installation and maintenance are simply not there) is right: 2140-0035 6.3V 0.04A
In the meantime I've ordered a bunch of JKL 345 from Mouser (60 Ecent/piece) From actual measurements in my 2116C the lamps (CM345)
draw:
register-bit positions: ~ 31ma @ 4.1V
inside the push-buttons: ~ 36mA @ 5.4V
compared to the spec: 40mA @ 6V
( I obtained CM345s from Mouser in 2013. "95 in stock", that would have left 83
after my purchase).