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References: [ +from:4cx250b@miamioh.edu: 327 ]

Total 327 documents matching your query.

201. Re: [Amps] issue with AL-1200 output -UPDATE NUMBER 2- (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Wed, 28 Jun 2017 13:59:05 -0600
Good answer. Only thing I'll add is that the results are altitude sensitive. A larger gap is required at higher altitude, but I'm not aware of any charts. I just use trial and error. Santa Fe is at 7
/archives//html/Amps/2017-06/msg00294.html (9,018 bytes)

202. Re: [Amps] SB220 step start blows fuses (score: 1)
Author: Jim Garland <4cx250b@miamioh.edu>
Date: Mon, 10 Jul 2017 08:10:54 -0600
I've been reading this thread for some time, and while I agree with many of the suggestions (i.e., light bulb testers, variacs), I don't believe any of these are necessary to diagnose this fault. The
/archives//html/Amps/2017-07/msg00045.html (16,048 bytes)

203. Re: [Amps] Clipperton L (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Fri, 21 Jul 2017 10:34:49 -0500
Kelly, IMHO you need an independent measure of the plate voltage, rather then assuming that the voltage divider network in the amplifier is giving you the correct reading. If you don't have an HV pro
/archives//html/Amps/2017-07/msg00078.html (8,048 bytes)

204. Re: [Amps] Fil transformer (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Thu, 10 Aug 2017 10:25:45 -0600
Kelly, I'm afraid I don't understand your comment. When I look at the schematic of the Clipperton L, it appears the RF is fed symmetrically to each side of the filaments, through .01 µF caps. On the
/archives//html/Amps/2017-08/msg00004.html (10,286 bytes)

205. Re: [Amps] Amplifier lifetime (score: 1)
Author: Jim Garland <4cx250b@miamioh.edu>
Date: Thu, 5 Oct 2017 08:59:49 -0600
Hi Manfred, I've got an NCL-2000 that has a similar history to yours. Like you, I seldom use it, but think it is a well-designed amplifier and arguably the nicest styling of any amp before or since.
/archives//html/Amps/2017-10/msg00057.html (10,452 bytes)

206. Re: [Amps] Amplifier Lifetime (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sat, 7 Oct 2017 13:03:54 -0600
Good comments, Mike. Re early 9500 issues, id add blower problems to the list. The original blowers had sleeve bearing motors, with the bearings poorly supported by the mounting flange. The newer blo
/archives//html/Amps/2017-10/msg00106.html (12,957 bytes)

207. Re: [Amps] 8877 - No plate current (score: 1)
Author: Jim Garland <4cx250b@miamioh.edu>
Date: Tue, 10 Oct 2017 12:04:09 -0600
Chris, Bruce might be correct that the filament is bad, but I"ve never known a filament to open up in an 8877, except for some tubes back in the 1970s which had defective filament welds. Another poss
/archives//html/Amps/2017-10/msg00117.html (10,084 bytes)

208. [Amps] 160m/80m homebrew amp (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Wed, 25 Oct 2017 14:03:18 -0600
Last year I finally completed my homebrew "contest-grade" duo-band amp, the end of an interminable three-year project. This past week I got around to adding photos and other details about the amp to
/archives//html/Amps/2017-10/msg00162.html (6,810 bytes)

209. Re: [Amps] Alpha 87 (not 87A) (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Tue, 7 Nov 2017 13:35:55 -0700
Id hazard a guess that most of the SSB splatter one hears comes from flat-topping (over-driving or under-loading) a linear amplifier. Someone should market a modern, improved version of the old Heath
/archives//html/Amps/2017-11/msg00055.html (10,855 bytes)

210. Re: [Amps] Glitch resistor + fuse? (score: 1)
Author: Jim Garland <4cx250b@miamioh.edu>
Date: Mon, 13 Nov 2017 10:09:29 -0700
Nearly all commercial amplifiers have glitch resistors in the HV line, typically about 50 ohms. A 10W resistor is fine, and a larger wattage one is fine also, but the larger power rating is unnecessa
/archives//html/Amps/2017-11/msg00143.html (10,982 bytes)

211. Re: [Amps] Glitch resistor + fuse? (score: 1)
Author: Jim Garland <4cx250b@miamioh.edu>
Date: Tue, 14 Nov 2017 17:25:14 -0700
Great comments, Jim. You're right, of course, about a 50ohm/10W glitch resistor being inadequate. I panicked when I read your comment and checked the schematic of my latest two power supplies. It tur
/archives//html/Amps/2017-11/msg00150.html (18,342 bytes)

212. Re: [Amps] Alpha 9500 Relays Needed (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Thu, 23 Nov 2017 05:55:30 -0700
Jennings RJ1A or the Kilovac HC1 relays are cheaper, widely available and make (IMHO) a superior alternative to the G41C in the Alpha 9500. They are about three times faster, have no contact bounce,
/archives//html/Amps/2017-11/msg00196.html (8,595 bytes)

213. Re: [Amps] Alpha 9500 Relays Needed (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Thu, 23 Nov 2017 07:15:30 -0700
Actually, they fit perfectly in the 9500, Tom, in the same location as the originals. John K1JD and I made the swap in his 9500 one afternoon, because he likes to run QSK and the Gigavac relays were
/archives//html/Amps/2017-11/msg00198.html (10,911 bytes)

214. Re: [Amps] Alpha 9500 Relays Needed (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Thu, 23 Nov 2017 08:28:00 -0700
Heres how its done, Tom. As I said, it was very easy, no stress on the control PCB, no cutting into the amp: https://sites.google.com/site/k1jdalpha9500relayconversion/ 73, Jim w8zr Sent from my iPad
/archives//html/Amps/2017-11/msg00200.html (12,597 bytes)

215. Re: [Amps] MFJ products (score: 1)
Author: Jim Garland <4cx250b@miamioh.edu>
Date: Tue, 5 Dec 2017 08:23:32 -0700
Jim makes very good points. In my station, I have several linear and switching power supplies. Over the years I've scavenged some "crowbar" overvoltage modules from old Lambda linear supplies and use
/archives//html/Amps/2017-12/msg00028.html (10,925 bytes)

216. Re: [Amps] MFJ products (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Wed, 6 Dec 2017 12:55:41 -0700
Id think a well-designed linear power supply would have a reliability edge over a similarly well-designed switching supply, assuming both had the same specs, and same parts and build quality, the rea
/archives//html/Amps/2017-12/msg00044.html (8,756 bytes)

217. Re: [Amps] MFJ products (score: 1)
Author: Jim Garland <4cx250b@miamioh.edu>
Date: Thu, 7 Dec 2017 07:59:36 -0700
I believe Manfred is exactly right. Linear power supplies tend to be less trouble-prone than switchers, but when they do fail, their failure mode can dump a significant overvoltage on their load. For
/archives//html/Amps/2017-12/msg00052.html (9,239 bytes)

218. Re: [Amps] Henry 2k-4 HV inductor (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Fri, 22 Dec 2017 14:08:54 -0700
Jim gives good advice here. A combination of a glitch resistor to limit flashover surge from the filter capacitor, plus an HV fuse close to the tube HV feed, is cheap and important protection. One ad
/archives//html/Amps/2017-12/msg00119.html (15,947 bytes)

219. Re: [Amps] Plate Choke Issue (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Thu, 4 Jan 2018 13:05:03 -0500
Hard to believe a flashover arc could jump over a quarter of an inch. Maybe theres a VHF/UHF parasitic of some sort. Did the ceramic just overheat and crack, or did it shatter? 73, Jim w8zr Sent from
/archives//html/Amps/2018-01/msg00042.html (9,878 bytes)

220. Re: [Amps] GS35B Idle current increasing (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sat, 10 Mar 2018 09:25:18 -0800
Paul, sounds to me like your filament voltage may be too low, or else you are cooking the grid by driving the tube too hard (grids are usually plated with gold or other metal that will evaporate if t
/archives//html/Amps/2018-03/msg00031.html (8,768 bytes)

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