Drake L-7
开云体育The top sheet metal is a solid sheet metal. You can see, very badly, through the fan. ? Removing the top panel: ok. To do a short test, it is a solution but in operation it is not reasonable, if only because it strongly modifies the path of the ventilation (airing). Without the cover, the air no longer comes from above by licking the filament seals and Eimac recommends. ? Maybe some have cut a small window blocked by a sieve and a plexiglass plate ? Eimac Technical data ? ? -- F1AMM Fran?ois |
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It seems your lid or top sheet metal has been changed. Mine has holes and I can see the tubes.
On Saturday, January 25, 2025 at 11:30:14 AM EST, Fran?ois via groups.io <18471@...> wrote:
The top sheet metal is a solid sheet metal. You can see, very badly, through the fan. ? Removing the top panel: ok. To do a short test, it is a solution but in operation it is not reasonable, if only because it strongly modifies the path of the ventilation (airing). Without the cover, the air no longer comes from above by licking the filament seals and Eimac recommends. ? Maybe some have cut a small window blocked by a sieve and a plexiglass plate ? Eimac Technical data ? ? -- F1AMM Fran?ois |
开云体育Why do you want to see these tubes all the time? ? It is the most reliable amp I’ve had. You can push this amp to all its limits and beyond, it just won’t die. Even when it starts to stink like burning socks. ? I used 2x 3-500ZG, for hours and hours, daily, for 15 years. ? The only thing I changed was the RF-choke and a replacement for the green pcb like 160m capacitor (by door knob types). I only opened it once a year to remove the just. That was all. Use it, push it, don’t worry about the colour of the tubes. Just stay within the current limits and you will be fine. (make sure the ventilation is running . ?) ? Great amp. ? 73, Evert ? / / ? From: [email protected] <[email protected]> On Behalf Of Fran?ois via groups.io
Sent: Saturday, 25 January 2025 17:30 To: [email protected] Subject: Re: [ham-amplifiers] Drake L-7 ? The top sheet metal is a solid sheet metal. You can see, very badly, through the fan. ? Removing the top panel: ok. To do a short test, it is a solution but in operation it is not reasonable, if only because it strongly modifies the path of the ventilation (airing). Without the cover, the air no longer comes from above by licking the filament seals and Eimac recommends. ? Maybe some have cut a small window blocked by a sieve and a plexiglass plate ? Eimac Technical data ? ? -- F1AMM Fran?ois |
开云体育> The only thing I changed was the RF-choke and a replacement for the green pcb like 160m capacitor (by door knob types). > I only opened it once a year to remove the just. That was all. ? Hello ? I am weak in technology (I am 75 years old). It seems to me that you are pointing out the two curious plate capacitors A = C41 (47 pF) and B = C42 (307 pF). ? ? Could you give me, precisely, the replacement capacitors that should be supplied. A url would be welcome. ? -- F1AMM Fran?ois De la part de Evert Bakker |
开云体育Hi Francois, ? I did not document my changes and sold the amp a few years ago. ? I remember the green capacitor (B) but not (A). That could easily be a memory leakage on my side but I couldn’t find it on the pictures before the restauration. . I don’t know the values of the (B) capacitor but replaced it with doorknob type (red). The red wire to the capacitor is spark-plug wire. On the attached picture you can see the new RF-choke was placed. When I looked at the photo’s I made, I saw I did change the indicator assembly as well. ? Do you have the service manual of this amp? ? 73, Evert ? / / ? From: [email protected] <[email protected]> On Behalf Of Fran?ois via groups.io
Sent: Sunday, 26 January 2025 06:08 To: [email protected] Subject: Re: [ham-amplifiers] Drake L-7 ? > The only thing I changed was the RF-choke and a replacement for the green pcb like 160m capacitor (by door knob types). > I only opened it once a year to remove the just. That was all. ? Hello ? I am weak in technology (I am 75 years old). It seems to me that you are pointing out the two curious plate capacitors A = C41 (47 pF) and B = C42 (307 pF). ? ? Could you give me, precisely, the replacement capacitors that should be supplied. A url would be welcome. ? -- F1AMM Fran?ois De la part de Evert Bakker |
开云体育Hello, ? > Do you have the service manual of this amp? ** No, I don't have the service manual for this amp. If you could share it with me, it would be appreciated. ? > I remember the green capacitor (B) but not (A). ** Your capacitor 'A' went with your old RF choke. ? ? A= 47 pF B= 307 pF ? Thanks for the images of your modifications; they can be very useful to me -- F1AMM Fran?ois De la part de Evert Bakker |
开云体育Francois, ? > I remember the green capacitor (B) but not (A). ** Your capacitor 'A' went with your old RF choke. ? Yes, you are correct. ? ? 73, Evert ? / / ? From: [email protected] <[email protected]> On Behalf Of Fran?ois via groups.io
Sent: Monday, 27 January 2025 07:02 To: [email protected] Subject: Re: [ham-amplifiers] Drake L-7 ? Hello, ? > Do you have the service manual of this amp? ** No, I don't have the service manual for this amp. If you could share it with me, it would be appreciated. ? > I remember the green capacitor (B) but not (A). ** Your capacitor 'A' went with your old RF choke. ? ? A= 47 pF B= 307 pF ? Thanks for the images of your modifications; they can be very useful to me -- F1AMM Fran?ois De la part de Evert Bakker |
开云体育I found the RF-choke I used : ?
? ? 73, Evert ? / / ? From: [email protected] <[email protected]> On Behalf Of Fran?ois via groups.io
Sent: Monday, 27 January 2025 07:02 To: [email protected] Subject: Re: [ham-amplifiers] Drake L-7 ? Hello, ? > Do you have the service manual of this amp? ** No, I don't have the service manual for this amp. If you could share it with me, it would be appreciated. ? > I remember the green capacitor (B) but not (A). ** Your capacitor 'A' went with your old RF choke. ? ? A= 47 pF B= 307 pF ? Thanks for the images of your modifications; they can be very useful to me -- F1AMM Fran?ois De la part de Evert Bakker |
开云体育From my own experience in blowing up two of those, is that RFC3 RF-choke purchased from RF-Parts is resonant on 30 meters when used in a 3-tube (8874) Alpha 76A amplifier.? Use in other amplifiers may differ.? ? 73, Dave, w6de ? ? ? From: [email protected]
<[email protected]> On Behalf Of Evert Bakker via groups.io
Sent: 27 January, 2025 20:32 To: [email protected] Subject: Re: [ham-amplifiers] Drake L-7 ? I found the RF-choke I used : ?
? ? 73, Evert ? / / ? From:
[email protected] <[email protected]>
On Behalf Of Fran?ois via groups.io ? Hello, ? > Do you have the service manual of this amp? ** No, I don't have the service manual for this amp. If you could share it with me, it would be appreciated. ? > I remember the green capacitor (B) but not (A). ** Your capacitor 'A' went with your old RF choke. ? ? A= 47 pF B= 307 pF ? Thanks for the images of your modifications; they can be very useful to me -- F1AMM Fran?ois De la part de
Evert Bakker |
开云体育I've just bought 4 from W8JI at CTR Engineering. Installed one in my AL-1500 and one in my home brew 2 x 3-500Z 160 to 10 amp. No problems on any band with those chokes. 73, Alek VK6APK. On 28/01/2025 8:06 am, Dave w6de wrote:
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开云体育Thanks Dave. Always “good” to hear the issues! In the L7 the RFC3 was ok (no issues in 15 years) ? 73, Evert ? / / ? From: [email protected] <[email protected]> On Behalf Of Dave w6de
Sent: Tuesday, 28 January 2025 01:06 To: [email protected] Subject: Re: [ham-amplifiers] Drake L-7 ? From my own experience in blowing up two of those, is that RFC3 RF-choke purchased from RF-Parts is resonant on 30 meters when used in a 3-tube (8874) Alpha 76A amplifier.? Use in other amplifiers may differ.? ? 73, Dave, w6de ? ? ? From: [email protected] <[email protected]> On Behalf Of Evert Bakker via groups.io ? I found the RF-choke I used : ?
? ? 73, Evert ? / / ? From: [email protected] <[email protected]> On Behalf Of Fran?ois via groups.io ? Hello, ? > Do you have the service manual of this amp? ** No, I don't have the service manual for this amp. If you could share it with me, it would be appreciated. ? > I remember the green capacitor (B) but not (A). ** Your capacitor 'A' went with your old RF choke. ? ? A= 47 pF B= 307 pF ? Thanks for the images of your modifications; they can be very useful to me -- F1AMM Fran?ois De la part de Evert Bakker |
