On Sat, Dec 11, 2004 at 08:26:20AM +1300, Ron W wrote: > Hi Elecrafters, > Does any one have any info on the MFJ miniature psu type 4103? Although it > is a sealed unit I wish to adjust the output to keep my internal battery > charged. The nominal output voltage is 13.8 and I wish to adjust to give > 14.2 as measured by the K2. I think the unit could be carefully cut open > and after adjustment sealed up again. Before starting on this exercise I > thought I would check with your collective wisdom. > 73 > Max/ZL4vv
I have one and it is a nice unit (no noise problems), but the output is not really high enough to charge the KBT-2. I measure 13.3 volts on the K2's internal display, while the KBT2 manual says the acceptable range is 13.6-14.0 volts. On a partially-discharged battery and after several days it brought the voltage from 11.1 to 12.4 volts, as measured on the K2's internal meter, which indicates that it partially charges the battery (I normally use a small linear supply, adjusted to 14.2 volts, which fully charges the battery). The 4103 is small and lightweight and suitable for travelling. I took it and my K2 to France earlier this year and when I unpacked, discovered that I had forgotten the power cord. Fortunately, the 4103 uses the same cord as desktop PCs, which is easily attainable practically anywhere. No switching is required when going between 120 and 240 volt mains systems. Unfortunately, it doesn't come with a schematic, so I don't know what is involved in modifying the unit for a higher voltage. If you are successful in raising the output voltage of the supply, please let the list know. 73, Bob N7XY _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com