Not controversy to me.? But I did want to point out that the solution has a tradeoff.? Not sure how obvious the tradeoff happens to be.
Harvey
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On 1/8/2022 12:31 PM, Mike Feher wrote:
As I said, maybe a "while longer". Why always so much controversy on here? - Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Harvey White
Sent: Saturday, January 8, 2022 12:25 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T CRT Question
Using a booster on a CRT is roughly equivalent to stuffing a new wick in an old candle and lighting both at the same time.
Increasing the filament voltage does make the cathode hotter, but the boosters don't do this for a little bit and try to clean off the cathode surface, they just increase the voltage. Since lifetime of the filament is related to the voltage/temperature, you're shortening the life of the tube.
Of course, that makes an unusable CRT useable, but for only so long.
Always tradeoffs.
Harvey
On 1/8/2022 11:52 AM, Mike Feher wrote:
It has been a long time since I had a 141T. However, I remember back
in the early 60's I worked at a Radio/TV repair shop and often had TVs
with dim video. There used to be a "booster" that would temporarily
fix the problem by increasing the filament voltage, hence the
emission. I do not know if that is feasible on the 141T design but it
may prolong the CRT's usable life a while longer if it is. 73 - Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115
-----Original Message-----
From: [email protected]
<[email protected]> On Behalf Of Dave McGuire
Sent: Saturday, January 8, 2022 11:35 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T CRT Question
On 1/8/22 11:30 AM, WB4IUY wrote:
I have a 141T mainframe that working, OK, but I noticed if I advance
the intensity (brightness) adjustment close to max the intensity
falls back off. It doesn't go out, it just gets dimmer. Any ideas on
this before I dig into it?
This is "close to" a classic symptom of a CRT with low emission. I believe the classic symptom is for the visible brightness to decrease and then increase again as the intensity control is increased. Chuck can probably explain better here.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
