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Don Bowey · November 29th 06, 05:57 PM posted to rec.radio.amateur.boatanchors

On 11/29/06 6:37 AM, in article
, "K7AAY"
wrote:

Given an SX-100. It doesn't work.

Chassis and interior in good shape, no corrosion. Lights fire up when
turned on. Attached Hallicrafters 3.2 ohm speaker (or headphones if
plugged in) hums, and I hear scratchy noises when I change across the
bands or switch to phono. S-meter moves across the dial when I spin the
sensitivity knob.

But, it doesn't actually receive anything, and the S-meter does not
move as I traverse the bands nor does it change as I move within a
band.

Suggestions on priorities for troubleshooting, by tube replacement or
otherwise, appreciated. I feel the detector is the place to start?
Have a multimeter, is all. In Portland (OR) Metro area.

0A2 voltage rectifier $6
5Y3GT rectifier $10
6AU6 1st mixer & crystal cal (1 ea) $10
6BA6 1650 KHz IF amp, 2nd mixer, 50.5KHz IF amp (1 ea) $8
6BJ7 detector/AVC/noise limiter $5
6C4 1st conversion oscillator & KHz IF amp (1 ea) $13
6CB6 RF amp $5
6K6GT audio output $8
6SC7 audio amp/BFO $9
12AT7 2nd conversion oscillator $13

Your Elmering would be appreciated. Thank you in advance.

If you don't have the manual, you should download it from the BAMA Mirror
site.

Read through the Test section and set all switches, pots, Band Switch,
frequency, etc to what is directed.

Next, using the page(s) showing the bottom view tube layouts with pin
voltages, measure all the voltages with a VTVM or equivalent and write down
all voltages that are off by more than about 10%. This should provide a
guide to where you have one or more defective components.

Please give a clue about your level of electronics. What town are you in?
I'm in Washougal (East about 15 miles on State 14, from I205 bridge). I
have a sig gen I may loan you, but can't let loose of my scopes. Maybe
later.

Don

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