I just put a new pointer drive "belt" (o-ring) into my G2800
controller. What a pain!
I think it is generous to describe the controller as "designed." I
don't recall a worse electro-mechanical creation, it must have been
created by several engineers that never talked to each other. They
obviously couldn't decide on connectors or soldered wires between the
boards, so it is a very delicate job to disassemble the boards to get to
the mechanics. The soldered wires are too tight to easily disassemble
the layers to be able to get to the drive "belt". Then the gear drive
disassembly is tricky - DON'T lose the small brass bushing/spacer, I
suspect it is unobtanium.
So much for the rant. The "belt" is an 028 sized o-ring and I bought
100 of them for $7. I will be glad to part with my extras if you send
me a SASE per my QRZ mail address. I'll send two back to all takers
until they are gone.
btw the new belt fixed the intermittent movement of the pointer. The
old belt had stretched/gone soft. A 500 ohm pot to the proper connector
pins also makes it easy to verify the servo and mechanics are working
properly.
Grant KZ1W
On 11/11/2011 12:50 PM, Bryan Swadener wrote:
> The G800/1000/2800 manual shows the lamp to be 12V/100mA, and running on a
> 12VDC regulated source that is not current-limited. As we know, a lamp's
> filament has a very low cold resistance, and inrush current typically exceeds
> 5X the running current. High inrush current causes mechanical shock to the
> filament and early failure. A resistor will limit the inrush current but
> also limit the running current. You need a "brick wall" current regulator.
> The ubiquitous and inexpensive LM317 can easily be configured to do that with
> one resistor. I did that many years ago with the GOW dial lamps in my olde
> Kenwood rig, and the lamps are still FB. Hint: the '317 will drop 1.2V so,
> use a lamp rated a bit lower than the supply voltage if you want full
> brightness. RS stocks the 317T for $2.69 but they can be found for pennies
> elsewhere (Mouser #863-LM317TG = $0.51).
>
> Single LEDs have a narrower dispersion angle and typically give you that
> "lovely" spotlight effect. Some LED lamp assemblies get around that by using
> multiple LEDs arranged in different positions. Another technique is to
> choose a wide-angle LED and/or scuff the lens so the spotlight effect isn't
> quite so bad.
>
> vy 73,
> Bryan WA7PRC
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