HP333A Distortion Analyzer meter help - Page 1
Forum section: electronics / repair

author: DonDoucette
author_rank: Newbie
timestamp: February 17, 2016, 01:54:40 am
content: Hello.This is my first post but not my last. I'm an electronics enthusiast that has been dabbling for more than 30 years. I recently moved and most of my gear has been in storage for a while until recently. Today I put together a new workspace in my basement and to my horror I found my HP 333A did not do well in storage, the meter movement has peeled and is a mess. I was wondering if one of you kind folks would be so kind as to take a high resolution photo of your 333A meter so that I might be able to get a sticker made to replace my mess, that is of course assuming one of you might have an old dinosaur 333A. LOL!Thanks for your time.DonI submit for your amusement the following photos;

author: lowimpedance
author_rank: Super Contributor
timestamp: February 17, 2016, 02:03:30 am
content: Oh dear that scale is well and truly fubar.Now just one thought, check out this meter scale software here;http://www.tonnesoftware.com/meter2.htmlto see if re creating it and printing on paper then laminating it / cutting and glueing to the original plate would be the cheapest method.I have used this software to create quite a number of custom scales and it works a treat.

author: edpalmer42
author_rank: Super Contributor
timestamp: February 17, 2016, 02:32:25 am
content: Another piece of software that can create custom meter scales and much more is calledGalva. It's 'postcardware'.

author: DonDoucette
author_rank: Newbie
timestamp: February 17, 2016, 03:41:44 am
content: Wow this is a sweet turn of events. Thank you, I will look at these and see if I can make something that will work. I thank both of you very much.

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 17, 2016, 04:26:05 am
content: I design my own scales using CAD some macros and a spreadsheet. Below is one example that will go into a circular slide rule I'm making out of a LP record.I can knock together one for you but I need dimensions. Logarithmic scales are not a problem but I'm not sure if that skewed scale is a precise log scale.

author: edpalmer42
author_rank: Super Contributor
timestamp: February 17, 2016, 05:01:23 am
content: Circular slide rules is one of the things that Galva has been used for - but not by me! Just the thought of trying to do something like that gives me a headache!

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 17, 2016, 05:12:37 am
content: It is much much simpler with spreadsheets since they practically fill themselves and the CAD command that will generate the command is generated automatically. I'm only doing it because it is easy, I'd never do it if it was tedious. Total of 2 hours in what you see on the file.

author: cvanc
author_rank: Frequent Contributor
timestamp: February 17, 2016, 01:38:13 pm
content: Oh wow that's so sad! Best wishes on the fix. I assume it got wet? Is there any other damage?

author: oldway
author_rank: Super Contributor
timestamp: February 17, 2016, 06:54:18 pm
content: It seems the same dial as 331A.The easiest solution would be to buy a defective 331a or 333a to be scrapped and change the dial.

author: TimFox
author_rank: Super Contributor
timestamp: February 17, 2016, 09:29:44 pm
content: Also, the 332 and 334 use the same meter face.

author: lowimpedance
author_rank: Super Contributor
timestamp: February 17, 2016, 10:48:44 pm
content: Why bother getting a scrapped one ! why not just get a better condition one.example :http://www.ebay.com/itm/HP-Agilent-333A-Distortion-Analyzer-/331776889608?hash=item4d3f719308:g:uqoAAOSwzgRWvnOWFrom the photo the analyzer looks generally tired anyway.Using the' free' version of the software and a little effort it would be much cheaper if not free to do the scale.Servicng the rest of the analyzer will be much more time consuming and not cost free.

author: uncle_bob
author_rank: Unknown
timestamp: February 17, 2016, 11:34:59 pm
content: HiI would spend some quality time taking a look in side the HP. Meters rarely do that for no reason at all. The meter movement it's self is pretty fragile. If you have a damaged movement, repairing it (or even replacing it) is going to be a hassle. You also could have water damage inside the instrument ...Bob

author: Andy Watson
author_rank: Super Contributor
timestamp: February 17, 2016, 11:54:12 pm
content: Quote from: uncle_bob on February 17, 2016, 11:34:59 pmI have two HP3400A meters that have that problem. It is the lacquer that holds the printing that is peeling. Whatever the mechanism is, it appears to be common to this era of HP meter movements. I am re-fabricating the scale using Tikz and LaTeX. I will then laser print the result on to a waterslide transfer - I hope! I hit a slight problem because the scale does not appear to be uniform - I can't decide if this compensation for the meter movement, or if it is a printing error (seems unlikely for HP).

author: uncle_bob
author_rank: Unknown
timestamp: February 18, 2016, 01:43:09 am
content: Quote from: Andy Watson on February 17, 2016, 11:54:12 pmHiPretty much all of these meter scales were "fudged" to improve the accuracy of the instrument. There always were little non-linearities in the system. It was easier to move the marks on the meter by a few percent than it was to add a bunch of circuits to try to kill the nonlinearity.Bob

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 18, 2016, 02:14:42 am
content: Quote from: uncle_bob on February 18, 2016, 01:43:09 amI was just going to say the same thing.Here are some linear ticks laid over the original scale. They only fit around 1.3V but the outer parts of the scale are stretched out.

author: uncle_bob
author_rank: Unknown
timestamp: February 18, 2016, 03:01:06 am
content: Hi*Many* years ago, I sold a full truck load of various HP distortion analyzers and audio generators. It took me three days of selling to move them all. I think I had to drop the price on the last of them to < $20 to get them moved after everybody had picked over the pile for days on end.I would love to tell you that I saved a coupe for parts "just in case" and have some spare meters. Not so much ... I'm not ever sure the only one that I kept still works. Looking at the price of these on eBay, there is one up for auction at $49.99. *IF* it sells at that price, it's a much newer / cleaner one than any I had. It is priced just a bit above the $35 that I was selling them for in ... 1980. They are a good instrument.My back still hurts thinking about that "adventure".My current audio analyzer is a bit newer and fancier (HP 8903A). I paid *much* less for it than the $195 "buy it now" 333A that is next up in price.A lot of this stuff gets dirt cheap when some guy named Bob is trying to dump the last of the truck load. If you shop long enough, you can find some amazing deals. You can't count your time as being worth anything of course, but hey, it's a hobby ...Bob (with the aching back ...)

author: DonDoucette
author_rank: Newbie
timestamp: February 18, 2016, 03:31:42 am
content: Quote from: lowimpedance on February 17, 2016, 10:48:44 pmWell yes I suppose my old 333A does look a bit tired but it did work well before I packed it away, I've had it for 10 years and I'm kind of fond of it so I wouldn't mind investing a bit of time and $ into it rather than taking a chance on another used one.

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 18, 2016, 07:08:15 am
content: @Andy WatsonI tried my hand at it. Created using free copy of DraftSight on Linux, Not precisely the same because I don't have that condensed font but seems usable.

author: Andy Watson
author_rank: Super Contributor
timestamp: February 18, 2016, 11:57:25 am
content: @HAL-42bMany thanks for that. I will have a go with those files and see how they fit.

author: Andy Watson
author_rank: Super Contributor
timestamp: February 18, 2016, 12:02:02 pm
content: Quote from: uncle_bob on February 18, 2016, 01:43:09 amThanks for confirming that. I have not measured the output from the meter but I assume that the fudge is to take care of mechanical artefacts in the meter movement.

author: uncle_bob
author_rank: Unknown
timestamp: February 18, 2016, 05:56:19 pm
content: Quote from: Andy Watson on February 18, 2016, 12:02:02 pmHiAnalog meter movements are amazingly linear devices. Of course they have been making them for a *long* time. They have been able to play with things like the magnetic field and armature to the point that it's probably as good as your eyes can see at a reasonable distance. Fancy ones have mirror scales on them to let you take out the parallax. Even so those meters have linear scales ....That's all assuming it is a DC meter and not one that is set up to directly read AC. They never did come up with a really good way to do a linear direct reading analog movement.Bob

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 18, 2016, 10:19:15 pm
content: uncle_bob read about Dr. Einthoven's String Galvanometer.https://www.eevblog.com/forum/projects/who-needs-a-scope/msg848436/#msg848436Response was good to around 100kHz, almost an oscilloscope. I don't believe it was ever tried using modern neodymium magnets.

author: uncle_bob
author_rank: Unknown
timestamp: February 20, 2016, 12:50:23 am
content: Quote from: HAL-42b on February 18, 2016, 10:19:15 pmHiOk, I stand corrected !!!Let's say a "practical AC reading panel meter" never seemed to come along.Bob

author: dom0
author_rank: Super Contributor
timestamp: February 22, 2016, 08:44:44 pm
content: Quote from: HAL-42b on February 18, 2016, 07:08:15 amThanks, I'll try this one with one of my 3400As, which also has a peeling meter movement. I think it's one of the earliest versions, the lamps on the chopper board are much larger than the later ones...

author: EndlessSummer
author_rank: Newbie
timestamp: September 25, 2019, 11:59:33 am
content: Ancient thread, I know, but I have the same peeling meter face problem on my 333A.Would it be simpler to just install a new digital readout meter instead of trying to repair the analog one?If not, I may just junk mine.

author: TERRA Operative
author_rank: Super Contributor
timestamp: September 25, 2019, 12:14:21 pm
content: Can you take a close up, high resolutoon photo of the bare meter face with some height and width measurements?