Low voltage and fan replacement

Trucker

I have had a 6600M ever since they first started shipping. Overall, it has been a great radio. Very few problems and a few that did require a return to the mother ship for a spa day. Some time ago I noticed that the fan didn't seem to be working well. So, I searched the forums and found posts about replacing the fan. I ordered one from Amazon that was exactly the same fan that was in the radio from the factory. ( Shark) I installed it and all seemed fine. Recently, I had problems that I associated with the latest version of SmartSDR I had installed. The radio front panel and SmartSDR on my pc would pop-up an error box saying that the connection to the radio had been lost. During that time I had determined that the fan I had installed didn't seem to be speeding up if I transmitted into a dummy load at 100 watts for an extended period of time. I have been running FRStack and Flexmeter to monitor voltage and fan performance. I ran the radio for several hours overnight and in the early morning I found that both the front panel and SmartSDR on my pc were sluggish and almost unresponsive. I checked FRStack and it showed 10.4 volts! And Flexmeter showed zero rpm's. I had ordered a new fan from Flex Radio because I felt the fan I bought from Amazon was defective. I did clean the power pole connectors and flowed some solder into the connector bodies and put them back together. The voltage level came up to 14.1 volts. But, would sag to 11.5 volts on transmit. Today, I bit the bullet and took the covers off of the radio and cleaned up the 30 amp fuse in the radio. Which by the way, isn't as simple to get to as the hardware manual makes it sound like it is. You have to remove two circuit boards and a metal plate to get to where the fuse is located. I removed the fuse and both pins were badly tarnished. I cleaned them up and inserted and reinserted them several times ( with Deoxit on the pins). While I was there I installed the new fan from Flex Radio as well. I put everything back together. ( only one spare **** that I can not find where it went) I reconnected my power supply ( Astron 35M) after checking voltage on the rear of the power supply ( 14.68 volts). Plugged everything in and powered on the power supply and then the radio. I ran FRSack and Flexmeter. FRStack showed 14.1 volts and Flexmeter showed 1040 rpm. I keyed the radio at 100 watts ( using the Tune button) into my dummy load for several minutes. At 100 degrees the fan speed had increased to 1200 rpm and voltage had dropped to 12.68 volts. Unkeying the radio cooled off to 74 degrees fairly quickly. And voltage returned to 14.1. I may make a few more changes by putting better ring connectors on the power cables and shortening the cables as well. ( original factory cables.....7 years old) I am considering opening up the power supply and turning up the voltage a bit more as well. Once I am sure everything is working like it should, I may upgrade again to see if the problem I had with that version was actually related to the fan and low voltage under load instead of being a software problem.

James

WD5GWY