[Elecraft] Re： XV50 Cooling

[Johnny Siu]

Hello Jerry,

I am afraid that my observation with my XV50 and XV144 is different.

These transverters are extremely hot if they are run at Elecraft's advertised rated output of 10W FM and 20W SSB.  The heat is from the power module and NOT the  attenuator resistors.

For both XV50 and XV144, there is neither internal fan nor holes in the PCB beneath the fan area.  

For XV432, there is an internal fan plus holes under the fan area.  You can make reference to XV432 operation manual.

As I mentioned in my earlier emails in this forum, I need to modify my XV144 in the way similar to the fan + PCB arrangement of XV432 so as to solve the heat issue. 

Of course, if you only run the XV50 at a couple of watts, there will be no heat issue.  For me, I would expect the transverter should run at the advertised rated output without any heat issues but unfortunately it is not the case.

73

Johnny VR2XMC







----- 郵件原件 ----
寄件人﹕ n0jrn <n0jrn at mchsi.com>
收件人﹕ Elecraft <elecraft at mailman.qth.net>
傳送日期﹕ 2010/6/3 (四) 12:58:45 AM
主題： Re: [Elecraft] XV50 Cooling

Thanks Don:

I bought this unit unbuilt from another list member and it is a very early 
model.  It has no vent holes at all !

I am driving with low power and therefore have the attenuator resistors 
bypassed.  So not worried about heat from that area.

I do have the feet on the transverter so air flow under it is good.

My concern stems from a reduction of output power after using the unit non 
stop for a period of time.  My fear is the power module is getting hot and 
falling off some.

Module was installed using the heat transfer pads correctly located.    I 
did not use heat sink compound.

This unit has the old style power module in it  ( M57735 )
This predates requirement of setting the PA bias in the XV50.

Just thought I would give it a little more air to help my PA live a little 
longer.    :-)

Guess I'll drop Gary a note and see if he has a spare set of panels.

Thanks again Don and have a great day.

73          Jerry              N0JRN

On 6/2/2010 10:36:44 AM, Don Wilhelm (w3fpr at embarqmail.com) wrote:
> Jerry,
>
> There are holes in the top cover that are "supposed" to be positioned
> above the attenuator resistors, and the new transverters have holes on
> the bottom on either side of the power module.  I am looking at a rather
> new XV50 right now that has come in to me for repair.  The builder did
> not position the top cover holes over the attenuator resistors, but the
> holes are in the cover.
> If you are driving the transverter from the low power outputs, the
> attenuator resistors are not used, so that source of heat is a no-op,
> but the resistors will heat up if higher power is used to drive the
> transverter.
>
> I do not believe additional ventilation holes are needed in most cases.
> If air flow below the transverter is available (do not operate it
> without the feet), the cooling is adequate.  It seems to me that some
> operators get concerned with any heat generation, but in reality, if it
> is cool enough you can place your hand on it for more than 30 seconds,
> it is not hot enough for concern.
>
> Earlier transverters did not have the holes in the bottom panel, and
> some very early ones did not have the vent holes in the top cover.  Yes,
> these may need additional vent holes, especially over the