[Kenwood] Kenwood TS-130S

[Steve]

At 07:58 AM 11/23/2011, D Langston wrote:
>Are these the same lamp ratings used  for the TS-520/820?

Not the least bit critical. The easiest thing to do is remove the top 
cover, see the size of the bulb (maybe cut it out and take it with 
you for comparision), then go to Radio Shack and look through their 
stash. The only ones I've ever found at RS even close to the right 
size have been the ones with green or red dye on the bulb. 
Fortunately, the dye washes off very easily with rubbing alcohol.

Next, you really want to reduce the voltage to the bulb using a 
series resistor to prolong the life and reduce the heat generated by 
the bulb (so it doesn't burn the S-meter's case, for example). 
Usually, it takes something like a 43 or 51 ohm 1/2 watt resistor; 
choose the resistor so the bulb still provides adequate illumination, 
which ever place you're going to put it, in the S-meter or VFO. 
You'll find the voltage to the bulb will be something like 10.5 to 
11.5 volts. As a side benefit, the resistor also provides some 
cushioning for the cold inrush current. Just use Ohm's Law to make 
sure you choose the power rating of the resistor properly so it 
doesn't burn up (measure the voltage across the resistor then 
calculate the power dissipated in the resistor). Also make certain 
the bulb does NOT touch the VFO dial or front of the S-meter, or it 
may eventually cause a burn spot.

Note that often, the filament in those el cheapo bulbs (relatively 
speaking) is usually offset inside the glass envelope; thus, you may 
have to rotate the envelope while watching the VFO dial or S-meter to 
find a position where the filament provides even and adequate 
illumination, then you may have to tape the bulb to keep it in that position.

SteveH, K0XP 



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