Re: Intermittent Loss of Pre-Driver signal
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? Hi Steve Re Fan Mod. Yes I agree, I do have a little noise with it running all the time, mine runs from early morning to mid evening most days( since retirement 8 months ago) and it used to get really hot. I had lived with it as before retirement use was limited during week and a bit of weekend use. It now runs very cool all the time.
Re device change, I only just thought of it, a little heatsink compound under the device before soldering tag, may had been a good idea. I think the manufacturer would consider the device to be flat hard mounted in that package. Someone mentioned about adjusting drive level, this may be a something to consider as well. Hope you get some operating time now you have it sorted. 73
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On 30 Nov 2024, at 5:51?AM, Steve G4ALG <steve@...> wrote:
? Thank you, Neil ZL3ADC, Dave ZS1DFR, and Bob W4JFA?
Neil:? For now, I will hold off applying a heatsink to Q102 while I consider internal fan modifications.? I didn't feel that I needed to run the fan continuously, as I use the rig a lot for monitoring the VHF and UHF CW centres of activity.? ?Today, I have implemented part of the modification written up by Richard PA7FA.? See:
I only added the 33 kohm resistor.? ?I was happy to let the temperature sensor detect the general internal temperature without pinning it to the heatsink temperature.? For this reason, I didn't go wild with the heatsink compound? :-)
Dave:? Thank you.? ?It's much easier to keep focus when we feel part of a team. It was a team effort.
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Bob:? A1: Yes, I used the exact same .? ?A2:?I can't find a date on the rig, but the serial number is 1002893, if this helps.? ?A3: I don't know anything about the history of this rig.? It was an eBay purchase, and I may be the third owner.? But it is in good general condition.? The rig came without a mobile mount, and there are no signs that the rig or the control head was used mobile.? But it may have been.? ?A4:? Regarding the mounting of Q102.? I also considered different ways of mounting the FET.? In the end, I decided that it was better to follow the construction method as used on thousands of production models rather than go it alone with a new approach.? I'm reasonably sure that having the tab and source (ground) plate of the FET in intimate contact with the copper foil of the PCB probably helps to keep the device cooler than if the casing of the FET is simply dangling in mid-air.
72/73
Steve G4ALG
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