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Products => Test Equipment => Topic started by: Haatveit on July 02, 2018, 07:00:57 pm

Title: Agilent 54642D runs really hot.. Normal?
Post by: Haatveit on July 02, 2018, 07:00:57 pm
I just got this today. Spent a bit of time cleaning it up, then powered it on and spent maybe 20 minutes familiarizing myself a little bit with it. It's a hot day (for Norway anyway), so my senses weren't really paying attention... Until I touched one of the front BNC terminals to unplug a 90* angle, and it was really hot. Like, almost too hot to touch - not quite that bad, but seriously pretty close. The fan works fine, it's brand new, and moves more air than the old fan did anyhow. It was only after touching the first BNC that I actually noticed that there's like seriously hot air wafting off of the front panel, it's all very warm, or in the case of anything made of metal, quite hot indeed.

It this normal...? The scope works fine otherwise.
Title: Re: Agilent 54642D runs really hot.. Normal?
Post by: bd139 on July 02, 2018, 08:28:01 pm
Yeah there’s a big ass chunk of metal with two massive heat sinks and hybrids bolted to it. This results in the BNCs getting hot.  They get quite toasty indeed. Make sure the fan works properly and it will be fine.

Even the lower end units get pretty hot.
Title: Re: Agilent 54642D runs really hot.. Normal?
Post by: AllTheGearNoIdea on July 02, 2018, 08:34:26 pm
I don’t even know what this is but my HP rack mounted universal counter gets silly hot if I remove the top cover as the fan does not draw the air over the components with the lid off.

Just a thought

Regards Chris
Title: Re: Agilent 54642D runs really hot.. Normal?
Post by: abraxa on July 02, 2018, 08:48:02 pm
http://wonghoi.humgar.com/blog/2016/07/24/agilent-54641d-fan-mod/ (http://wonghoi.humgar.com/blog/2016/07/24/agilent-54641d-fan-mod/) might be relevant here.
Title: Re: Agilent 54642D runs really hot.. Normal?
Post by: Haatveit on July 02, 2018, 09:48:25 pm
That's a nice fan mod there, I might do the same. I noticed that putting an external fan near the vents on the bottom of the unit, even on very low settings, made an enormous difference. Must be completely still air inside there, takes very little to alleviate it.

But, the mere existence of the mod also answers my question, so that's two birds with one stone. Cheers!
Title: Re: Agilent 54642D runs really hot.. Normal?
Post by: nicbul on November 07, 2018, 09:25:40 pm
I just acquired a 54641D on the weekend and the first thing I noticed about it was how hot it ran!  It did fail the user cal however that may have been a cabling/connector issue.  Came across this thread after a quick search and I decided to install the blower fan today.  Works like a charm and the temperature stabilizes quite quickly now.  The breeze from the front panel isn't quite that tropical!

Of course, I do notice that placement of the instrument really impacts the operating temperature.  The difference in temperature between the scope being on the bench with the tilting bale out and the scope being flat on a shelf is about 10C.