[Kenwood] TS-930 vacuum-fluorescent display problem

[Garey Barrell]

Ken -

My experience has been that they DIM with use, not rejuvenate.   I have 
seen several with varying brightness segments, and they have all been 
"high use" units.

There are "chop shops" for Kenwood and others that part out working 
radios, since like cars, they are more valuable in pieces than as a 
whole.....   Sad but true...

73, Garey - K4OAH
Atlanta

Drake C-Line Service Manual
<http://www.k4oah.com>



Ken & Marlene wrote:

>My winter-time project TS-930 has a problem with the vacuum fluorescent display. Parts of some digits are noticeably dimmer than the rest.
>
> I've checked the voltages and waveforms against the schematic, and everything appears OK. The filament is getting 7Vp-p at about 20 KHz, the gate signals are swinging between -44V & +2V and the segment signals are swinging between -44V & +5V.
>
> Some scribe once suggested that vacuum fluorescent displays that haven't been used for long periods of time seem to lose their brightness ( does the phosphor get lazy? ) and can be rejuvenated by letting them run continuously for several days. I've tried that, with the frequency set to 28.888.88 but can't see much, if any, improvement.
>
> Any help or suggestions would be most welcome.
>
>
>Ken, VE3FIT
>
>  
>