My Mistake: L7 HV calibration pot
My memory is failing. ? The HV calibration pot on the L7 ?is not accessible from the rear panel. 73, Evan, K9SQG
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Evan
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#81586
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Re: Small lamp reference for Drake L7
Tim, Not sure what to say. ? All the L7s I've owned or serviced had an access hole on the back panel for inserting an insulated tool for adjustment. ?Now the one on the L4B is different though. I
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Evan
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#81585
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Re: Small lamp reference for Drake L7
Evan No I have not done that in the manual from Drake it notes " not user accessible" tell me about it. Evan I have purchased many parts for the Drake amps from you in the past and have used them.
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amfone
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#81584
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Re: Small lamp reference for Drake L7
You¡¯ve posted a new topic about meter shunts. Please go to the .io group and re-post your question with a new appropriate topic title. Otherwise people researching this issue in the future won¡¯t
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Bill Blodgett. AI5RP
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#81583
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Calibration of L7 plate voltage resistors
----- Forwarded Message ----- From: Evan via groups.io <k9sqg@...>To: [email protected] <[email protected]>Sent: Saturday, January 4, 2025 at 06:53:45 PM ESTSubject: Re:
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Evan
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#81582
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Re: Small lamp reference for Drake L7
Tim, Have you already attempted a calibration via the pot on the back panel of the RF deck? 73, Evan, K9SQG
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Evan
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#81581
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Re: Small lamp reference for Drake L7
Hello group. I need to replace the meter shunts for the Drake L7, LV and HV reading low. From the schematic Drake used 8 2.3 meg 1/2 watt resistors it appears from the schematic and manual pictures
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amfone
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#81580
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Re: T4X part id needed
Jim: Not sure which one is "blown". But all four ceramic feedthroughs shown in the pic are .001 uf/350V rated. *But*.....your HV line (+650VDC) is missing where the unused hole is. Is this what you
By
VE7PS
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#81579
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T4X part id needed
Can anyone recommend a subsitute for a blown feed-thru cap that I need ? Appreciate any help Regards W6TTY
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Jim W6TTY
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#81578
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Re: TR7 next problem
yes it was a very pleasant surprised when I turned it on and it worked, The problem I have now id that when i SWITCH FROM lsb OR usB TO cw i get a signal in the receiver 5 over 9 and if I press the
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Jim Harris
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#81577
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Re: Small lamp reference for Drake L7
Thanks a lot for the reference, appreciated ! :)
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Mohamed VA2MKX
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#81576
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Re: R4C Sherwood audio mod questions
I stand corrected. Rob, NC0B Sent: Saturday, January 04, 2025 6:52 AM To: [email protected] Subject: Re: [DRAKE-RADIO] R4C Sherwood audio mod questions The computed -3 dB high-pass turnover
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Rob Sherwood
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#81575
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Re: R4C Sherwood audio mod questions
Hi Floyd, Thanks for pointing that out. I¡¯ll look at the board in my R-4C and see which is correct. It likely doesn¡¯t make much difference with the inverting input impedance. Rob, NC0B Sent:
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Rob Sherwood
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#81574
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Re: TR7 next problem
Well, there ya go! Nice catch. Doesn't it feel good? That is an interesting failure. Just a wild guess but I am thinking the lead had a weak spot, maybe a nick or a spot of corrosion, that caused it
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Jim Shorney
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#81573
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Re: R4C Sherwood audio mod questions
Thank you to all and to Rob especially. This is all very helpful - all gold. Nigel [email protected]> wrote:
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nigel patterson G3YDT
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#81572
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Re: T-4XC Sideband adjustments?
Tweak the cxr osc....such that the low end rolls off the same on LSB? as it does on USB.? ?That's as good as it will get.
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Jim VE7RF
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#81571
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Re: R4C Sherwood audio mod questions
The computed -3 dB high-pass turnover frequency is 123 Hz for 330 uF, and 204 Hz for 200 uF.? Pick either one based on personal roll-off preference. Paul, W9AC
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Paul Christensen
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#81570
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Re: R4C Sherwood audio mod questions
Rob - maybe it makes no difference at all, but there is a discrepancy in the component values for the AMP-4.? The text specifies the inverting input capacitor as 200 uF while the schematic shows it
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Floyd - K8AC
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#81569
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Re: TR7 next problem
I just wanted to let you know I managed to get the high VCO working. I was removing transistors and checking them on my tester, and when I removed Q504 and noticed that the Gate lead was broken off
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Jim Harris
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#81568
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Re: Speaker?
At a guess the smaller magnet was Alnico 5 or some other metallic magnet material while the larger one was ceramic. Ceramic magnets are very powerful but do not conduct magnetism well so tend to be
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Richard Knoppow
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#81567
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