Hi Harvey

*Afraid not.*?? Solar panels are very popular in Australia with at least 1/3rd of homes having roof top solar panels.? In my street of about 30 homes more than half have solar.

What this tends to do on sunny days, with so much solar energy in a street is to push up the nominal 230v mains voltage to sometimes in excess of 250v.

Glenn
vk3pe

I used to do this with scrounged angle iron from bed frames people would throw
out on trash day.? Some are pretty wide and I can attest to the wood strip
method to keep things centered.? A sawzall makes quick work of cutting them.

Peter


On 3/30/2024 7:10 PM, Ed Breya via groups.io wrote:

I have a bunch of fairly heavy aluminum 90 degree angle-iron pieces scrounged
up long ago. They are about 2" by 3/16" flats by 30" long, and easy to drill
holes anywhere and attach with the usual 10-32 screws into the side members of
almost any rack. Usually it's enough to just support the side rails of the
gear firmly, from front to back. I put the heaviest items on the rails, and
stack lighter gear on them, so only a few big items are actually mounted, and
serve as shelves for the rest. It's easier to reconfigure too, unless you need
to relocate the big stuff.

So, you don't really need a shelf pan, but be sure the gear can't move too far
side to side and fall through. The wide enough angle stock mostly assures
this. I drop in wooden shims on the sides if there's any doubt. Also be sure
the rack is stout enough to not bow open - sometimes you need cross pieces
here and there to hold the sides together

Ed

I have a bunch of fairly heavy aluminum 90 degree angle-iron pieces scrounged up long ago. They are about 2" by 3/16" flats by 30" long, and easy to drill holes anywhere and attach with the usual 10-32 screws into the side members of almost any rack. Usually it's enough to just support the side rails of the gear firmly, from front to back. I put the heaviest items on the rails, and stack lighter gear on them, so only a few big items are actually mounted, and serve as shelves for the rest. It's easier to reconfigure too, unless you need to relocate the big stuff.

So, you don't really need a shelf pan, but be sure the gear can't move too far side to side and fall through. The wide enough angle stock mostly assures this. I drop in wooden shims on the sides if there's any doubt. Also be sure the rack is stout enough to not bow open - sometimes you need cross pieces here and there to hold the sides together

Ed

That's what I kept thinking - especially since everything else that's connected to the base is negative.? Could that be a typo?

Barry - N4BUQ

-8.8V seems much more plausible, with the emitter -9.4V

Hugh Gilbert

On Fri, Mar 29, 2024 at 4:02?PM n4buq <n4buq@...> wrote:

Chuck,

Thank you so much for that.? I couldn't tell if that was a + or a - in front of the base voltage but that shows it clearly as +.

Thanks again,
Barry - N4BUQ

----- Original Message -----
> From: "ChuckA" <chuck@...>
> To: "HP-Agilent-Keysight-equipment" <[email protected]>
> Sent: Friday, March 29, 2024 2:38:15 PM
> Subject: Re: [HP-Agilent-Keysight-equipment] HP-1421A Q109 Voltages

> Here's a clean scan of the section you are looking at.
>
> ChuckA
>
> On 3/29/2024 3:16 PM, n4buq wrote:
>> Does anyone have a readable schematic for the A101 board in a 1421A?? I have a
>> paper manual on order but until that arrives, I would appreciate finding out
>> the voltages shown for Q109 (Page 5-16, Figure 5-9).? From what I can tell, the
>> online scan appears to show:
>>
>> C: +48V
>> B: -8.8V
>> E: -9.4V
>>
>> The value for B is particularly blurry but would like to know for sure what all
>> of those are.
>>
>> Thanks,
>> Barry - N4BUQ
>>
>>
>>
>>
>>
>>
>
> --
> See Early TV at:
>
>
>
>
>
>

Thanks Henning re *delta marker*. Been a while since I operated this SA. I just confirmed thats the level issue.

Re *the cap across the mains*, that's what i suspected initially as I had it happen on other? HP test gear. Getting to that area though appears very difficult to confirm that's all it is.
The mains voltage here can rise to over 250v on a sunny day, as I have solar panels on the roof.

Glenn

On Mar 30, 2024, at 17:23, Dave Miller <ve7hr@...> wrote:

?I have run out of floor and bench space and it's time start filling up the racks I have stored away. :-(
Unfortunately most of the equipment does not have mounting ears. Last time I looked at them they are hard to find and very expensive.
What's everyone thoughts about using 4 post ventilated shelves like this?

<dummyfile.0.part>

They are rated 120 kg a shelf.
I can source them locally cheaper and faster than a set out mounting ears on Fleabay with shipping. And I can adjust the height instead of getting multiple sizes of ears.
It's also easier to wrestle something on a shelf than mount it in a rack with screws. Or at least that is my limited experience.
And If I want put another piece in rack it seems easier.
What do the experts have to say?
Thanks
Dave?
VE7HR

I have run out of floor and bench space and it's time start filling up the racks I have stored away. :-(
Unfortunately most of the equipment does not have mounting ears. Last time I looked at them they are hard to find and very expensive.
What's everyone thoughts about using 4 post ventilated shelves like this?


They are rated 120 kg a shelf.
I can source them locally cheaper and faster than a set out mounting ears on Fleabay with shipping. And I can adjust the height instead of getting multiple sizes of ears.
It's also easier to wrestle something on a shelf than mount it in a rack with screws. Or at least that is my limited experience.
And If I want put another piece in rack it seems easier.
What do the experts have to say?
Thanks
Dave
VE7HR