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Author Topic: Rookie user HW101 Warm up question  (Read 436 times)
KD0ZGW
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Posts: 963




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« on: March 30, 2019, 09:07:41 AM »

Contest weekend.  Wanted to see how the old rig would do in crowded band conditions.

Fired up the HW101 and let it warm up for about 5 minutes.  Started listening and it seemed almost completely deaf.  Checked antenna selection and all was good.  Trolled across the band in the silence and a couple minutes later the audio level jumped and suddenly I was hearing a very crowded band.

Warm up or dirty pot issue?


Worked a station in FL and overall found the selectivity on the old rig wasn't bad.  Wish the tuning had a Vernier though.


KD0ZGW
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KX4QP
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Posts: 285




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« Reply #1 on: March 30, 2019, 10:51:52 AM »

Even with indirectly heated cathodes, I wouldn't expect to take more than, at most, five minutes to warm enough to hear output; one to two minutes is the commonly quoted figure.  Half an hour is recommended for stability, but that's to let everything inside come up to thermal equilibrium.  Some of the more sophisticated tube sets were set up to bring the filaments up gradually, to extend filament life, but that shouldn't take a half hour, that's the five minutes figure.

I'm no Heathkit expert (just got an SB-102, don't even have a power supply yet), but I'd start by checking the RF gain and AF gain pots.  Do you hear crackling sounds (after full warm-up) when adjusting either knob?  That's the most common symptom of a dirty pot...
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W5RKL
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Posts: 1104




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« Reply #2 on: March 30, 2019, 01:05:59 PM »

The HW-101 should never take 2 to 3 minutes to warm up before you hear any
signals whether it's the calibrator of off the air signals. The typical time from a
cold power up to where you begin hearing signals is between 10 and 20 seconds.

I suspect your problem is a "heat" related problem.

When you power up the HW-101, with the RF Gain control set fully CW and meter
switch set to ALC, the meter should peg fully to the right. After about 10 seconds
or less, the meter should begin to drop back towards zero. Does this happen?

Also, rotating the RF Gain control CCW should result in the S meter rising above zero
and eventually after rotating the RF Gain control CCW the S meter should peg fully
to the right. Does this happen?

73
Mike W5RKL
www.w5rkl.com
RMC(SW) USN RET
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