[Kenwood] Kenwood TS-130S

Mon Nov 21 19:34:00 EST 2011

Bryan,
I have the bulbs as I replaced the one in the VFO. How do you get to 
it? Is it easily accessible if I the off the bottom cover?
I just went in and removed the J5 jumper on the diodes that prevent 
transmission to the WARC bands. The diagrams in the manual were no help 
in finding it. I pushed wires around and found every jumper but J5. 
After about 10 minutes or so, I finally found it.
David
KW4DH
On 11/21/2011 5:18 PM, Bryan Swadener wrote:
> David,
>> They're just "Grain Of Wheat" lamps with a T1 (3mm diameter) bulb& wire leads. IIRC, Kenwood used 14V/25mA lamps. Your local hobby supply store should have them.
>> Their lifetime is determined by the supply voltage/current and the number of times you cycle the power on/off. Each increase of 5% voltage/current results in a decrease of approximately 50% in lifetime. Likewise, a decrease of 5% voltage/current results in an increase of 50% in the lifetime.
>> The number of times you cycle the power on/off has an effect as well. Incandescent lamps have a low cold resistance. This results in an inrush current pulse of around 5X or more of the running current. This is a huge mechanical shock to the filament and causes early failure. Leaving it ON isn't practical but you can limit the inrush current with a simple current source. The LM317L voltage regulator works well, is easy to implement, and costs pennies. The LM317L datasheet shows how to use it as a current regulator, using one resistor. Since the 317 will drop around 1.25V, use it with a 12V lamp on a 14V source. Mine's been working for many years... so far.
>> vy 73,
> Bryan WA7PRC
>> From: David KW4DH
> Subject: [Kenwood] Kenwood TS-130S
> To: kenwood at mailman.qth.net
>> Before I adventure inside the case of my TS-130S, is there a bulb to
> illuminate the S meter? I have gone back and forth over the schematic
> but I can't seem to find any indication.
>> David
> KW4DH
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