Bill, I'm not sure which Harbach mod(s) you are referring to.? There is a step-start for the high voltage, step-start for the filaments, replacement rectifier and capacitor board, and which sort of determines what else you might do.?
When I rebuild supplies I replace just about everything except the power transformer, and with components that have better ratings than the original.? One important mod is to replace the 5K 7wt resistor on the underside of the supply with a 20 watt equivalent; your unobtainable ALC pot will thank you for it. I also place one or two fans on top of the supply.? I use a model that is 220v but will start and run reliably on 110v.? It is so quiet you can't hear it and it brings the case temperature down dramatically. 73, Evan, K9SQG -----Original Message----- From: Bill <[EMAIL PROTECTED]> To: drakelist@zerobeat.net Sent: Mon, 28 Jul 2008 10:56 pm Subject: Re: [drakelist] Drake L-4B I just found out the the L-4B?has the?Harbach mod and the bleeder resistors were removed to eliminate excessive heat. ? Is there anything else I need to do to the power supply? ? Thanks! ? 73 de Bill K9BUB --- On Mon, 7/28/08, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: From: [EMAIL PROTECTED] <[EMAIL PROTECTED]> Subject: Re: [drakelist] Drake L-4B To: drakelist@zerobeat.net Date: Monday, July 28, 2008, 2:41 PM I would think 20A would be fine unless the run is long, then I'd opt for 30A.? Be aware that pin arrangements for the plug and socket change for the various ratings. Even if the PS is working ok with the amp, I always replace the 5K 7wt resistor on the underside of the supply with a 5K equivalent, 20 watt rating.? When the original resistor fails, it takes out the ALC pot that also contains the standby switch; these haven't been available for decades. -----Original Message----- From: Duane Calvin <[EMAIL PROTECTED]> To: drakelist@zerobeat.net Sent: Mon, 28 Jul 2008 2:34 pm Subject: Re: [drakelist] Drake L-4B I ran a 20A line for my Alpha 99.? Works great. ????????73,? Duane?? AC5AA At 01:23 PM 7/28/2008, you wrote: Just bought a Drake L-4B amp and while I am waiting for the amp to arrive I had the electrician over. He wants to know what everyone is running for their 240V line. 15, 20 or 30 amp service. ? Thanks! ? 73 de Bill K9BUB Duane Calvin, AC5AA Austin, Texas www.ac5aa.com The Famous, the Infamous, the Lame - in your browser. Get the TMZ Toolbar Now!