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Author Topic: Stupid SB-200 Tricks  (Read 7443 times)
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N8ETQ
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Mort


« on: March 12, 2016, 10:26:51 AM »



       You seldom see these fail but I just lost a
Plate Blocking Cap on an SB-200. My entire shop is
regulated at 115VAC via a GRC 1581-A Automatic
Voltage Regulator and as a final test I have taken
to cranking my bench variac up to about 130 on the
dial to simulated real world AC service.

       With 115 VAC in my variac puts out about
122 VAC when set at 130 on the dial.  This thing
had a nasty bias problem caused by "Sloppy Assembly",
"Poor storage conditions" and someone "Converted"
him to 11M.  (Conversion was limited to removal
of all the band switching and input coils
to make room for another 572B)  Yikes!!


       Anyway since it's so trashed my cust. wants
it on 6m.

Enjoy

/Dan






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Patrick J. / KD5OEI
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WWW
« Reply #1 on: March 14, 2016, 12:23:51 AM »

Seen the 3 tube mod in a Suburban mobile with a Leece-Neville alternator and three under-hood transformers, and rectifier/filter in a separate box. It was on 10M. He claimed 1KW PEP output on SSB.
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Radio Candelstein - Flagship Station of the NRK Radio Network.
kb2vxa
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I modulate, therefore AM


« Reply #2 on: March 14, 2016, 07:39:16 AM »

The tank coil looks about right, but isn't the tuning cap left over from 11M just a little big for 6M?
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73 de Warren KB2VXA
Station powered by atomic energy, operator powered by natural gas.
WD8BIL
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« Reply #3 on: March 14, 2016, 09:05:22 AM »

Be very judicious in your layout on 6M. Those tubes in parallel love to take off at 21 and 42MHz.
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N8ETQ
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Mort


« Reply #4 on: March 16, 2016, 08:49:44 PM »


kb2vxa

   I yanked a couple 4 stator plates out of it. need a few
minutes to slap it on the sweep gen. to see if more need
to go.

   I also disconnected 1/2 of that load cap.

Thanks

/Dan






The tank coil looks about right, but isn't the tuning cap left over from 11M just a little big for 6M?
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N8ETQ
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Mort


« Reply #5 on: March 16, 2016, 08:54:46 PM »


  Yeah,

          Thats what I got now Buddly, an oscillator. No covers
with it, that huge hole for the boxer fan that's "Glued in"...

Why me?HuhHuh?   Can't bias it off hard enough to tame..

Hence, I drink!

73 and thanks,  Gud to c u at the BA meet.

/Dan



Be very judicious in your layout on 6M. Those tubes in parallel love to take off at 21 and 42MHz.

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kb2vxa
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I modulate, therefore AM


« Reply #6 on: March 17, 2016, 05:40:12 PM »

Glued in? When Super Glue first hit the market I naively believed the commercial and glued a transformer to a panel to avoid taking it all apart and doing some serious drilling and blasting. Eventually it fell on a wafer switch, POW ZAP BANG. One fire and destroyed wiring later I made a solemn vow, never believe advertising claims. Oh, I repaired the Ranger, de-yellofied it and since the statute of limitation ran out decades ago the AM Gangstas gave WB2UZD FB reports on rock bound 3885. (;->)

That having been confessed, er, said, since you have a power oscillator have you considered RF welding the fan, adding an external coil and using it as a diathermy machine?
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73 de Warren KB2VXA
Station powered by atomic energy, operator powered by natural gas.
W2JBL
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« Reply #7 on: March 17, 2016, 07:59:20 PM »

WB2UZD? Do you remember me? I was WA2OMH and used to work you back about '71 or '72 on 3885. before that I used my father's call as a "boot" W2GOW dad caught me and I had to get my own ticket... about 6 months ago I found a cassette tape of 75 AM from back then and had about 30 seconds of WB2UZD and WA1MYQ on 3885 before the tape self destructed...
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