- 1. [Amps] Testing amp with no air flow (score: 1)
- Author: "Rick Stealey" <rstealey@hotmail.com>
- Date: Thu, 19 Oct 2006 12:20:41 +0000
- I will soom be ready to apply power for the first time to a homebrew 8877 amp. I need to make adjustments under the chassis with the tube filament lit and was wondering how long I can run the 8877 wi
- /archives//html/Amps/2006-10/msg00192.html (6,959 bytes)
- 2. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "Robert B. Bonner" <rbonner@qro.com>
- Date: Thu, 19 Oct 2006 08:07:35 -0500
- About 30 seconds Then PHZIT... Seriously, there's no spec for that because you aren't supposed to do it. Reason, you have a 150 watt light bulb in 1/16th the amount of space of a 150 watt light bulb.
- /archives//html/Amps/2006-10/msg00193.html (9,719 bytes)
- 3. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "Robert B. Bonner" <rbonner@qro.com>
- Date: Thu, 19 Oct 2006 08:10:04 -0500
- Actually that's 50W but the same deal I will soom be ready to apply power for the first time to a homebrew 8877 amp. I need to make adjustments under the chassis with the tube filament lit and was wo
- /archives//html/Amps/2006-10/msg00194.html (8,961 bytes)
- 4. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>
- Date: Thu, 19 Oct 2006 14:17:38 +0100
- I can't answer that question directly, but how about stretching clear Saran wrap over the base of the chassis? It balloons up alarmingly, but it keeps the air in, lets you see what you're doing, and
- /archives//html/Amps/2006-10/msg00196.html (8,320 bytes)
- 5. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "Harold Mandel" <ka1xo@juno.com>
- Date: Thu, 19 Oct 2006 09:23:25 -0400
- Dear Rick, When tweaking my dual 3CPX1500A7 amp under the RF deck what I did was to fabricate a piece of 1/8" thick Plexiglas clear plastic in the same fashion as the lower plenum cover with the addi
- /archives//html/Amps/2006-10/msg00197.html (8,314 bytes)
- 6. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: Steve Thompson <g8gsq@eltac.co.uk>
- Date: Thu, 19 Oct 2006 14:39:17 +0100
- If the only adjustment you need to make is to the heater voltage, add a couple of feedthroughs or similar to the cathode compartment wall and connect them to the heater via 10k resistors. Using a DVM
- /archives//html/Amps/2006-10/msg00198.html (8,154 bytes)
- 7. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "k7rdx" <k7rdx@charter.net>
- Date: Thu, 19 Oct 2006 07:23:41 -0700
- I just checked fil voltage on my 8877 here (No blower ) watched it ramp-up to 4.9vac in less than 10 secs and then pulled switch...No heat felt on tube base in this short time interval...What`s the b
- /archives//html/Amps/2006-10/msg00199.html (9,180 bytes)
- 8. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "Harold Mandel" <ka1xo@juno.com>
- Date: Thu, 19 Oct 2006 11:07:10 -0400
- It's a question of economics and habit. If you feel confident in powering up ceramic devices without any airflow you are the one who footed the bill. The whole idea of the airflow scenario is that is
- /archives//html/Amps/2006-10/msg00200.html (8,404 bytes)
- 9. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "Tom W8JI" <w8ji@w8ji.com>
- Date: Thu, 19 Oct 2006 13:30:39 -0400
- Tubes can overheat with just filament power although it takes a while. A few minutes probably won't hurt but I'd sure keep my eye on the seal temperature. 73 Tom ____________________________________
- /archives//html/Amps/2006-10/msg00201.html (8,014 bytes)
- 10. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "k7rdx" <k7rdx@charter.net>
- Date: Thu, 19 Oct 2006 12:06:09 -0700
- tube _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
- /archives//html/Amps/2006-10/msg00203.html (9,979 bytes)
- 11. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "Bob Maser" <bmaser@tampabay.rr.com>
- Date: Thu, 19 Oct 2006 15:31:30 -0400
- Blow air down thru the fins from up on top. Bob W6tR _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
- /archives//html/Amps/2006-10/msg00204.html (10,760 bytes)
- 12. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: K8MLM@aol.com
- Date: Thu, 19 Oct 2006 19:51:30 EDT
- There is an easier way. Attach the shop vacuum to the top of the tube and work on the bottom side. That's how I did some under side work on my Alpha 77. But in this case I hooked the shop vacuum to t
- /archives//html/Amps/2006-10/msg00207.html (11,175 bytes)
- 13. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "Robert B. Bonner" <rbonner@qro.com>
- Date: Thu, 19 Oct 2006 21:24:44 -0500
- OK so here's what we've done to provide potential ways to safeguard the tubes and tweak the bottom side. 1. Wife's hairdryer at base or fins running on cold. 2. Wife's vacuum / shop vac sucking throu
- /archives//html/Amps/2006-10/msg00208.html (12,447 bytes)
- 14. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>
- Date: Fri, 20 Oct 2006 07:43:33 +0100
- In what way marginal? The recommendation was actually to "stretch clear Saran wrap over the base of the chassis," but maybe I should also have added: Seal. It. Down. With. Tape. It's 100% effective.
- /archives//html/Amps/2006-10/msg00211.html (8,467 bytes)
- 15. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "Larry Carman" <lncarman@swbell.net>
- Date: Fri, 20 Oct 2006 10:29:33 -0500
- That's good news to know Theo. Thanks for passing it along. The 8877 would probably evaporate after a long period of filament operation without air flow. Larry N5BIP "I've tested the filament on the
- /archives//html/Amps/2006-10/msg00214.html (8,412 bytes)
- 16. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "Robert B. Bonner" <rbonner@qro.com>
- Date: Fri, 20 Oct 2006 10:55:20 -0500
- Yes the YC-156 is a huge Brutus tube. One with 3CX15K internals. But also a 15V 15 amp filament (a 225 watt light bulb) If that had been an older designed tube like say a 3CX3000 the anode could have
- /archives//html/Amps/2006-10/msg00215.html (8,034 bytes)
- 17. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "k7rdx" <k7rdx@charter.net>
- Date: Fri, 20 Oct 2006 09:38:17 -0700
- I wired my 3CPX5000A7(YC-156/179) so the blower has to be turned on before anything and timed for 5 mins of blower AFTER all power has been removed...And yer right, the tube is a brute...Jim... K7RDX
- /archives//html/Amps/2006-10/msg00216.html (9,329 bytes)
- 18. Re: [Amps] Testing amp with no air flow (score: 1)
- Author: "Jim Nowotarski" <N3GOO@ARRL.NET>
- Date: Fri, 20 Oct 2006 19:41:51 -0400
- For what it's worth, when I brought up my homebrew 4CX800A amp, I bought 4 temperature crayons (Tempilstiks) from McMaster-Carr and marked the tube on the ceramic and metal at the seals. I don't reme
- /archives//html/Amps/2006-10/msg00217.html (8,209 bytes)
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