• July 18, 2023, 1:13 p.m.

    I built an electrostatic speaker for a school project, back in the day. It worked quite well, but wasn't very loud. Not great for the kind of music I was listening to at the time.

  • Foundation 1514 posts
    July 18, 2023, 2:01 p.m.

    To get a decent sound level, even with a Quad ESL, you need a polarizing voltage of about 5kV, I believe!

    David

  • Members 243 posts
    July 18, 2023, 3:08 p.m.

    I like the pretty wood.

  • Members 395 posts
    July 18, 2023, 4:15 p.m.

    Hi,

    However, they called them electrostatic speakers at the time they implemented them. The term is right in the service manuals. So I shall stick with that nomenclature lest I royally confuse the folks who still work on the old things. ;)

    And there is another lost concept: The Service Manual for electronics. I think I penned about the last of them for modern electronics when at Ericsson in the 1990s.

    Stan

  • Members 1737 posts
    July 18, 2023, 4:35 p.m.

    At HP, there was a section in the user manual called Theory of Operation. I don’t see that anymore. Maybe I’m buying the wrong stuff. I would love to see such a section in camera manuals.

  • Members 395 posts
    July 18, 2023, 5:29 p.m.

    Hi,

    Oh, yes! Such a section in everything for me, please!

    I used to write those myself. And a service section. Such as how do you get this fool thing apart? And, also, how to put it back together.

    I don't particularly need a set of MAPs, Maintenance Analysis Procedures. Flow charts, really. They take up a lot of space. And I can logically flow on my own. Those Theory of Operation sections come in handy there.

    Somehow all this got lost when it comes to modern photographic gear. And now I have to Wing It. Sigh.

    Stan

  • Members 599 posts
    July 18, 2023, 5:33 p.m.

    Didn't they release schematics?

  • Members 1737 posts
    July 18, 2023, 5:34 p.m.

    Or reverse engineer it.

  • Members 1737 posts
    July 18, 2023, 5:38 p.m.

    Somewhere along the line, as the FRUs got bigger, schematics became less and less useful in the field, and started to be looked upon as trade secrets.

  • Members 976 posts
    July 18, 2023, 5:46 p.m.

    Ha. We are trying for 2 years with HE*/HE formats. Very slow going.

  • Members 599 posts
    July 18, 2023, 6:46 p.m.

    I didn't know this. It has been a long time since purchasing schematics for complex repairs.

  • Members 50 posts
    July 18, 2023, 7:08 p.m.

    I am enjoying this wonderful "off-topic" topic. 😀

    As I mentioned, my father was a TV/radio repir technician who learned his trade in the Navy servicig radar equipment. He continued his education at the Delehanty Institute in New York- it was a Police and Firefighters' College that later offered courses in electronics.

    I spent many hours in his shop and learned how to service the then-popular RCA 6-30 Chassis- 6 up-front adjustment knobs and 30. tubes. I learned to solder, use the VTVM and the oscilloscope and diagnes certin issues by symtoms on the sceen I got an EDUCATION on how to RESPECT high voltage and remember the "CAGE" with the HV rectifier tube and its infamous cap! I remember about those "hot chassis" on table radios and that infamous anode cap on the CRT! We had file drawers full of SAMS schmatics! The De Luxe TV sere mad my A drea, Stromberg-Carlson and Setchell Carlson.

    There was the famous family saga of Mrs. and Mrs. G. Mrs. G. used to call my dad at home, oftentimes late at night, with her EMERGENCIES! The TV was on the blink and she could not manage her unrulay grandchildren when they could not watch their favorite program- Howdy-Doody! On one occasion the "black spot" on the screen was found to be a dead hornet that managed to electriuct itself or did of starvation. Seemed that Mr. G.was tired of paying the service call feese so he dedided to change the "light bulbs" at the back of the TV- himself. There was a DIY tube tester and a small stock of tubes at he corner grocery store. He invested in a "cheater cord" to bypass the interlock on the Masonite peg board cover and opened metal "CAGE" within. This time it was a REAL EMERGENCY call. Mrs. G exceidedly exclaimed that her huspand was "changig the light bulbs when he suddenoy began to shake and could not let go the the TV set". Dad grabed his tool box, me, and a lenght of rope from he back yard, called and ambulance and we headed off the the G's home. Well ,Mr G. was still stuck to the TV and was unconscious. He did shut off the set but did not know about residual cahrges and received a bad electrical shock, sufferede burns and long term nerve damag to hs hands. He soild his underwar too -ugh! Dad puledl him off the TV with that rope and by then, the ambo arived the attendants catred Mr G. off to the hospital. The odor of buning flesh and hair reamind the room. Good thing Mrs. G. did not water the plant that she kept atop the TV set and spilled water onthe floor! Something about a high potetial ground? I' m a bit rusty on my electrical theory! I did, after all, opt to becme a photgaher and except for flash repairs and tinkerg with antique radios , I deligate most of that to the experts. Besides, unlike my old radios and some OLD reaming HAM gear, most of my home electronics become obsouete long befre they break down. Mostof the old-tyme repar guys are retired or dead or the say- "SORRY MAN- I haven't seen that chip since 1979!

    Now, if folks could conduct their PHOTOGTAPHY conversatsions with such good will and spirits- this wil be an awesom forum! ... --- ... QRT , y'all!

  • Members 1662 posts
    July 18, 2023, 7:28 p.m.

    Great (though scary) story!

    And a big YES to that last paragraph! Can we have some of that excitement and collective use of knowledge/experience in other topics as well, please? Or should we ask the admins to change this into a audio & music forum? 😅

    I have hundreds of questions about lenses (and devices they were used in) up to thrice my age and would be very thankful for knowledgeable and more experienced people helping out finding some answers. 👍

  • Foundation 1514 posts
    July 18, 2023, 8:04 p.m.

    Your wish is my command. I wasted some time trying to take some snaps of my "audio equipment" for you (I never thought it would be so difficult, and I am not satisfied with the results).

    This will show the disorganised nature of one part of my "study":

    IMG_6224_a1.jpg

    Two details:

    IMG_6209_a.jpg

    IMG_6211_a.jpg

    And, because I know that you like to see things larger than life:

    IMG_6212_a.jpg

    Obvious underlying thought: "This sunny weather does show up the dust!"

    I actually spent this morning cleaning the dust from the inside of my computer. I have never lived anywhere before where so much dust accumulates in such a short time. I put it down to the fact that Vienna is full of building sites, which involve tearing down 200 year old buildings.

    The dust looks much worse on the photos than in real life, but when I have cleaned the gear, as I do from time to time, I will attempt to make better photos, which will not make you sneeze!

    David

    IMG_6212_a.jpg

    JPG, 1.2 MB, uploaded by davidwien on July 18, 2023.

    IMG_6211_a.jpg

    JPG, 1.4 MB, uploaded by davidwien on July 18, 2023.

    IMG_6209_a.jpg

    JPG, 4.6 MB, uploaded by davidwien on July 18, 2023.

    IMG_6224_a1.jpg

    JPG, 6.0 MB, uploaded by davidwien on July 18, 2023.

  • Members 1737 posts
    July 18, 2023, 8:07 p.m.

    I can remember seeing schematics even for ICs. Except for some analog ones those days are gone. Can you imagine what the schematic for a ThreadRipper would look like?

  • Members 395 posts
    July 18, 2023, 8:14 p.m.

    Hi,

    All my audio gear are residents of the Shelves of Obsolete Electronics. Several Tuners and Amps. At least two Receivers. Open Reel, Cassette and -get this- an 8 Track Recorder. One of those Philips early CD players with the active audio filtering. Big and heavy with all the guts in it. And at least one turntable. Maybe two, but the second would be a Rec O Kut 78 rpm from WBNR.

    Maybe this Winter, I'll dig it out one by one and eBay it. Same for piles of old test equipment. Anybody want enough Tektronix TM-500 stuff to recreate the bridge set of Battlestar Galactica 1979? :P

    But no one gets my HP 8566B spectrum analyzer. $80k in 1980. Dang thing is like the Energizer Bunny. And still a dream to use as long as I'm under 24 GHz.

    Stan

  • Members 395 posts
    July 18, 2023, 8:18 p.m.

    Hi,

    Ouch. Zapped and held by the Second Anode. That'll leave a mark! Hopefully he lived a long time after. And never messed with those kinds of light bulbs again.

    I messed with 50 kW AM Broadcast transmitters for a while. That HV would make most, if not all, of you disappear. Good Old Gates (nee Harris).

    Stan

  • Members 50 posts
    July 18, 2023, 8:47 p.m.

    This is not even half of it! This is only a "tip-of-the-iceberg" at home. My lovely wife tolerates this as long as it is somewhat camouflaged by the house plants. There is anoter set up in the studio. And, would you believe, there's another in the bedroom. Nowadas it's mostly Denon equipment- not too terrible! 20230718_162807-01.jpeg

    20230718_162807-01.jpeg

    JPG, 125.0 KB, uploaded by EdShapiro on July 18, 2023.