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frank <frank@invalid.net>: Jul 09 10:48AM Just a little update, I've tried regular neon indicator bulbs (most of them start conduction at around 75V) and only one showed oscillations and only at low max current ratings. https://www.dropbox.com/s/padumhxip1697n1/VI-neon.zip?dl=0   Here're a few pictures of the V/I traces of regular small lamps. Tilted traces are lamps with internal resistor, so the resistor is tilting the trace. Frank

Jeff Liebermann <jeffl@cruzio.com>: Jul 09 09:37AM -0700 On Sun, 9 Jul 2017 10:48:58 -0000 (UTC), frank <frank@invalid.net> wrote:   >Tilted traces are lamps with internal resistor, so the resistor is >tilting the trace. >Frank   The one that oscillated (IMG_1950.JPG) looks very much like your original video. <https://www.youtube.com/watch?v=DeKPkG5T1xc> It would be helpful if you increased both the vertical and horizontal gain of your photos so some detail could be seen:   If you happen to have a few identical NE-2 lamps, put three in series to get something close to the 200v as in the gas discharge tube. Then, compare the displays.   Also, smaller JPG's please. This test does not require 12 megapixel images.     -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

Cursitor Doom <curd@notformail.com>: Jul 09 03:10PM Gentlemen,   The link below shows a scope trace of the output of a linear PSU (voltage 4.7VDC) with about 300mV of 100Hz ripple riding on it. This PSU is in- circuit under load from the boards it supplies. Normally I would assume a filter capacitor to be at fault here, but they all check out fine so something else is causing this ripple. Note there is a characteristic 'knee' on the high peaks and I'm thinking this must be indicative of *something* trouble is, I don't know what. If anyone recognises this waveshape and knows what causes it, that'd be "awesome" - as our American friends describe everything. Check it out:     https://www.flickr.com/photos/128859641@N02/35684682551/in/dateposted- public/

Foxs Mercantile <jdangus@att.net>: Jul 09 10:29AM -0500 On 7/9/2017 10:10 AM, Cursitor Doom wrote: > If anyone recognises this waveshape and knows what causes > it, that'd be "awesome"   Not sure what's causing it, but it's indicative of a non- linear load. The "knee" is where the load transitions from one value to a smaller value.       -- Jeff-1.0 wa6fwi http://www.foxsmercantile.com   --- This email has been checked for viruses by AVG. http://www.avg.com

Dimitrij Klingbeil <nospam@no-address.com>: Jul 09 01:14AM +0200 On 07.07.2017 19:36, rickman wrote: > pin 3 look? I would expect it mostly near 48 volts dropping slightly > below 24 volts during retrace. Pin 7 should definitely have a > significant pulse voltage on it.   Did you check D360 (the "bootstrap" diode from 24V in the pump circuit)?   It may be shorted and pulling the "pumped" supply "down" to 24V. The IC will most likely need the pumped supply for one half of the screen only.

Dimitrij Klingbeil <nospam@no-address.com>: Jul 09 01:29AM +0200 >> A ringer is the best instrument to check for shorted turns.   > not sure what a ringer is, but im pretty sure i dont have one. you > mean like a tone generator, and you move it around the yoke ?   Look up "impulse winding tester", that's the high voltage version. Ring testers work the same way, with V rather than kV scale drive.

mhooker32@gmail.com: Jul 08 06:58PM -0700 On Saturday, July 8, 2017 at 7:15:05 PM UTC-4, Dimitrij Klingbeil wrote:   > Did you check D360 (the "bootstrap" diode from 24V in the pump circuit)?   > It may be shorted and pulling the "pumped" supply "down" to 24V. The IC > will most likely need the pumped supply for one half of the screen only.   i did pull up one leg of D360 and checked it, it checked good. pin 7 never goes anywhere near 24 volt. there is a .5 volts poorly defined waveform, almost looks like ripple. im thinking it should be a 24v sawtooth? i am thinking something on the board may be pulling down pin 7?   thanks

mhooker32@gmail.com: Jul 08 07:27PM -0700 > > will most likely need the pumped supply for one half of the screen only.   > i did pull up one leg of D360 and checked it, it checked good. pin 7 never goes anywhere near 24 volt. there is a .5 volts poorly defined waveform, almost looks like ripple. im thinking it should be a 24v sawtooth? i am thinking something on the board may be pulling down pin 7?   > thanks   just to be clear, the pin 7 is 1/2 volt(.5) ripple like form   thanks

John-Del <ohger1s@gmail.com>: Jul 08 07:38PM -0700 > > will most likely need the pumped supply for one half of the screen only.   > i did pull up one leg of D360 and checked it, it checked good. pin 7 never goes anywhere near 24 volt. there is a .5 volts poorly defined waveform, almost looks like ripple. im thinking it should be a 24v sawtooth? i am thinking something on the board may be pulling down pin 7?   > thanks   You can't check this diode with a dmm... I posted above:     "I didn't read back through all the posts, but if you haven't, check the pump up diode. The anode will be connected to the Vcc and the cathode to the pump up pin of the vert IC. A weak diode here will cause all sorts of havoc (don't check it with a dmm - they often sag under load)."

Foxs Mercantile <jdangus@att.net>: Jul 08 03:47PM -0500 > dimmer to control the speed? I would use a dimmer rated at 600W or > greater. (The saw runs on my 300W inverter in my car, so it's not a huge > power user).   This may or may not work, but it is a true triac speed controller <http://www.ebay.com/itm/401361481384>     -- Jeff-1.0 wa6fwi http://www.foxsmercantile.com   --- This email has been checked for viruses by AVG. http://www.avg.com

amdx <nojunk@knology.net>: Jul 08 02:38PM -0500 On 7/7/2017 3:18 PM, John-Del wrote: >> component level on the VCR's but I did note the TV tech replaced a lot >> of boards.   > If you want to make money and do it quickly, you can't be changing boards unless they're particularly cheap. Component level is all we ever did but the problem these days is that even companies like Samsung are not providing full schematics. This means I spend time looking at datasheets and using the "representative" circuit as a guideline for doing component level repair. Fortunately, parts that manufacturers don't sell us can usually be sourced from China. I never order one, I always order 10.   Arrgh! I wrote a long response and then I got a white screen of, "I lost it all." The purchaser did put the pcb in the mail one day after Ebay's suggested mail by date. Now I just wait to see if it is the same pcb I sent him. I don't know if it will help me but I have posted the picture of my marking on the pcb to several sites, even maid a faux ebay listing (showing the markings on my pcb) with a very high price so no one will buy it. I worked at at electronics repair center in the 80's and early 90's, I did all the VCR repair, which was all component level repair. It was a great place to work, the owner was an authorized service center for over 80 companies, which meant we had service manuals for most of them. I performed service on over 11,000 VCR's in the 10 years I was there. It's common to have the same problem, so after you have repaired a few, you know what it needs by the customers description. When VCR prices got near $250 to $200, people started making the decision to buy a new one rather than repair. I had thoughts about DVD repair, but glad I didn't start that because the prices came down quick on those. I got out of repair and moved to Florida. My timing was pretty good, I told one of the other tech's I was leaving and he might want to take over my repairs, (I made the most money at the shop), but by the next year when I visited he said he was only coming in 3 days a week, and had another job.

"Ian Field" <gangprobing.alien1@virginmedia.com>: Jul 08 07:10PM +0100 "Don Kuenz" <g@crcomp.net> wrote in message news:20170707d@crcomp.net... > undocumented PSUs. They may even have the service manual that you seek > or a pertinent schematic. The only downside is that you need to sign up > to access the forum.   Found the right schematic.

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