SX-115 Low sensitivity .5 kc Selectivity UPDATE
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Good morning all ,
I've completed the replacement all the components in the selectivity? RC Circuits, tested associated tubes, and confirmed all is working, except the .5 kc selectivity. No improvement.?
Next steps
1. Check 2.2 pF cap C85
2. Check? 390 pF caps C83 & 84?
3. Align 50 kc IF
I did confirm the grounding of the RC circuit when in .5 kc position.? The selectivity switch is working as expected.?
73 Steve w8tow? |
开云体育Well Steve, I guess you checked by ohmmeter that the contacts closed [ or opened ] in position 6, and made sure the solder joints were ?really conducting, 1 Ohm or less for closed. ???at some time, that knotch filter mentioned before should be tried, and the alignment I guess too. Perhaps you can stick a scope in there and see if sheds any ideas??? The experts on this are hiding or doing yard work I guess. ? From: [email protected] [mailto:[email protected]] On Behalf Of Steve Marquie
Sent: Tuesday, October 29, 2024 7:02 AM To: [email protected] Subject: Re: [HallicraftersRadios] SX-115 Low sensitivity .5 kc Selectivity UPDATE ? Good morning all , I've completed the replacement all the components in the selectivity? RC Circuits, tested associated tubes, and confirmed all is working, except the .5 kc selectivity. No improvement.? Next steps 1. Check 2.2 pF cap C85 2. Check? 390 pF caps C83 & 84? 3. Align 50 kc IF I did confirm the grounding of the RC circuit when in .5 kc position.? The selectivity switch is working as expected.? 73 Steve w8tow? _._,_._,_ -- don??? va3drl |
开云体育
Guys,?
This was a topic with much input in 2021. I would suggest visiting?the message archive from 02/27/21 through 03/08/21.
Walt Cates, WD0GOF
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From: [email protected] <[email protected]> on behalf of don Root <drootofallevil@...>
Sent: Tuesday, October 29, 2024 1:06 PM To: [email protected] <[email protected]> Subject: Re: [HallicraftersRadios] SX-115 Low sensitivity .5 kc Selectivity UPDATE ?
Well Steve, I guess you checked by ohmmeter that the contacts closed [ or opened ] in position 6, and made sure the solder joints were ?really conducting, 1 Ohm or less for closed. ???at some time, that knotch filter mentioned before should be tried, and the alignment I guess too. Perhaps you can stick a scope in there and see if sheds any ideas??? The experts on this are hiding or doing yard work I guess. ? From: [email protected] [mailto:[email protected]]
On Behalf Of Steve Marquie ? Good morning all , I've completed the replacement all the components in the selectivity? RC Circuits, tested associated tubes, and confirmed all is working, except the .5 kc selectivity. No improvement.? Next steps 1. Check 2.2 pF cap C85 2. Check? 390 pF caps C83 & 84? 3. Align 50 kc IF I did confirm the grounding of the RC circuit when in .5 kc position.? The selectivity switch is working as expected.? 73 Steve w8tow?
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Steve Marquie
don Root
waltcates