Michael,
I have rebuilt several supplies and have used both the Harbach Electronics board and the HeathkitShop board; only difference is that the latter has space for equalizing resistors for the diodes whereas the former you have to add them directly to the diodes themselves should you choose to add them. Make sure you replace the 5K 7wt resistor on the bottom of the cabinet with a higher wattage; I use two 10K 10 watt resistors in parallel to get the functional equivalent but a higher wattage. Make sure you replace the two 50 K 50 wt resistors as well. As a final touch, I add a 220 v fan to the top, ones that are known to start and run reliably on 110 vac, can't hear them run, and the installation is not permanent. Good luck with your project. 73, Evan -----Original Message----- From: Michael & Sue Trussell <[email protected]> To: [email protected] Sent: Wed, Feb 23, 2011 8:23 pm Subject: [Drakelist] L4B power supply fire! Just as I have heard all the stories of power supplies being destroyed, my L4B power supply did just that. Turned on the amplifier just like I always have heard a big bang and looking to find the noise and then saw the fire. Turned off the L4B and removed the 220 volt plug from the wall just in time to see my power supply burning. I then carried it outside until the fire was out. I had planned to upgrade the power supply but now it’s got to happen. I would like to ask about the Heath Kit shop, power supply module upgrade. Has anybody used this unit? When this unit is purchased does this unit replace both sets of 220uf 450 volt old yellow caps and all the resistors and diodes? Any comments, ideas, or suggestions would be appreciated! Thank you Michael J Trussell KA8ASN _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
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