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Bo-Lennart <bo-lennart.karlsson@telia.com>: Sep 27 10:48AM -0700 Hi all out there. I found a transformer in my basement. I don't know if its a audio-output transformer or just a power transformer. On top it's stamped "GALVIN MANUFACTURING CORPORATION", and a model #: "25B31296-E" and a serial# ( ???? ) "138226" At bottom there is 8 solder lugs, stamped: "1 to 8". And at one side is 8 screw connector, labeled as "3A 12 11 2B 2A 10 1A 9".   To me it looks more like a tube output transformator, more than a power transformer. It seems to be from the 1940 or somewhere around there.   Anyone know what it is, and have some kind of "schematic" of the transformer.   Many thanks in advance   Bo-Lennart Karlsson Falun, SWEDEN

Bo-Lennart <bo-lennart.karlsson@telia.com>: Sep 27 11:39AM -0700 Den fredag 27 september 2019 kl. 19:48:15 UTC+2 skrev Bo-Lennart:

"pfjw@aol.com" <peterwieck33@gmail.com>: Sep 27 11:54AM -0700 On Friday, September 27, 2019 at 1:48:15 PM UTC-4, Bo-Lennart wrote:   > Many thanks in advance   > Bo-Lennart Karlsson > Falun, SWEDEN   Galvin Manufacturing is the company that produced Motorola products out of Chicago, Illinois, USA. It is easy enough to trace it out using a small AC power-supply and a good True RMS VOM.   https://www.radioremembered.org/xfmr.htm takes you to the RMA (Radio Manufacturers' Association) Transformer color-code for power transformers. Motorola, being a founding member of the RMA would typically follow these codes, but for their military stuff that followed a different code, sometimes.   Audio Output Transformers usually have Green-Black-Green (and mixes) on the secondary side, and Blue-Red-Blue (and mixes) on the primary side.   Note that transformers often have multiple taps on the same winding. So: a) Using your Ohms setting isolate the various windings from each other. A single winding will show continuity, but with variations in resistance from one tap to the next. b) Isolate the windings from the lowest total resistance to the most total resistance - this is trickier than it seems as you want to include all taps, but measure the complete winding, not an internal tap. Even more so, if, for instance, you have a 5V winding off a 120 V primary - it will have a lower resistance than the primary winding - more on this later. Bundle each winding and all the taps together so as not to mix them up. c) Starting with the lowest-resistance winding, apply some reasonable, but low, AC voltage -say about 20 VAC or so. d) Measure voltages on the other windings. By experimentation, you should be able to discern the purpose of the transformer, the primary winding and any taps, and the secondary windings as well.   As an example: A typical audio power for tube equipment here in the US would get 120 VAC on the primary side, have a B+ winding that might give something between 325 and 450 VAC, one or two 6.3 V filament windings and, perhaps a 5 V filament winding. That would be as many as five total windings. Some few even have dual primary windings to accommodate multiple input voltages. So, it is complicated.   An audio transformer may have multiple taps, but the turns ratio between the primary and the full secondary will be fixed, and there will be only two windings in total.   Take your time - it is almost entirely unlikely that you will be able to trace *that* transformer by its part number.   Hope that helps.   Peter Wieck Melrose Park, PA

Fred Smith <fredsmith@thejanitor.corp>: Sep 27 10:21PM > Many thanks in advance   > Bo-Lennart Karlsson > Falun, SWEDEN   Audio output transformers generally don't interleave the "E" and "I" laminations, and may have an obvious bit of waxy paper between the block of E and I laminations. Power transformers almost invariably do interleave the laminations (I've never seen one that didn't).

Phil Allison <pallison49@gmail.com>: Sep 27 06:10PM -0700 Fred Smith wrote:   ----------------------   > Audio output transformers generally don't interleave the "E" and > "I" laminations, and may have an obvious bit of waxy paper between > the block of E and I laminations.   ** Small transformers intended for "single ended" operation are like that - the rest are like power transformers.   The OP is being a real PITA by NOT supplying any info on how big his unit is or any of the winding resistances.   A pic would be revealing too.       .... Phil

amdx <nojunk@knology.net>: Sep 27 08:18PM -0500 On 9/27/2019 5:21 PM, Fred Smith wrote: > the block of E and I laminations. Power transformers almost > invariably do interleave the laminations (I've never seen one that > didn't).   Well Fred, if you are correct in your assertions, you will be Fred, if Phil gives us his wisdom and it doesn't agree, we will find your aliases. Mikek

Phil Allison <pallison49@gmail.com>: Sep 27 09:40PM -0700 amdx wrote:   ------------     > Well Fred, if you are correct in your assertions, you will be Fred, if > Phil gives us his wisdom and it doesn't agree, we will find your aliases. > Mikek   ---------------------------   FYI to all:   The Mikek troll knows more about "Aliens" than aliases.   Talks to them all the time, on long range AM radio.       ..... Phil

Michael Terrell <terrell.michael.a@gmail.com>: Sep 28 05:43AM -0700 On Friday, September 27, 2019 at 1:48:15 PM UTC-4, Bo-Lennart wrote: > It seems to be from the 1940 or somewhere around there.   > Anyone know what it is, and have some kind of "schematic" of the transformer.   > Many thanks in advance     25B31296-E is typical of Motorola part numbering.   It crosses to a NSN part which is a 120VAC 60Hz input power transformer:   https://nationalstocknumber.org/nsn/5950-00-648-0400   NSN are inventory numbers for items bought by the government.

"Dave M" <dgminala@mediacombb.net>: Sep 28 09:03AM -0500 Bo-Lennart wrote:   > Many thanks in advance   > Bo-Lennart Karlsson > Falun, SWEDEN   Galvin Manufacturing was the original radio manufacturing company that eventually became Motorola. They started making consumer radios, and then invented a record player that could be installed in an automobile. Thus, came the name MOTOROLA, from MOTOR cars, and the old victROLA record player (from RCA). The 25B31296 part number identifies as a Motorola transformer, having the following characteristics from the US military stock system:   5950-00-648-0404 Features MRC Parameter Characteristics ABKQ Center to Center Distance Between Mounting Facilities Parallel to Length 2.625 inches nominal single mounting facility single center group ABKR Center to Center Distance Between Mounting Facilities Parallel to Width 2.375 inches nominal single mounting facility single center group ABTB Mounting Hole Diameter 0.125 inches nominal single group ACZB Frequency Rating 60.0 hertz nominal single component ACZC Input-Output Phase Relationship Three phase to three phase single component ADAQ Body Length 3.875 inches nominal ADAT Body Width 3.875 inches nominal ADAU Body Height 3.500 inches nominal AKNA Inclosure Type Hermetically sealed AKPV Mounting Facility Quantity 4 single group AXGY Mounting Method Flange single group and unthreaded hole single group BPLC Winding Function and Quantity 1 primary single component and 2 secondary single component CWJS Winding Operating Voltage 145.00 ac volts nominal single component 1ST secondary CWJS Winding Operating Voltage 12.00 ac volts nominal single component single primary CWJS Winding Operating Voltage 5.80 ac volts nominal single component 2ND secondary TTQY Terminal Type and Quantity 8 threaded stud and 7 tab, solder lug     No indication of the equipment it was used in, but more than likely a piece of military equipment. Since the primary is specified as 12VAC, and secondaries as 145V and 5.8V, it is likely to be a power transformer from a vibrator power supply used in a military radio of some sort. Don't know how the 3-phase spec works into it... could just be how the vibrator side of the transformer was described.   Cheers, Dave M

legg <legg@nospam.magma.ca>: Sep 27 04:58PM -0400 On Fri, 27 Sep 2019 06:55:28 -0700 (PDT), John-Del <ohger1s@gmail.com> wrote:     >On plug in, the power supply standby supply turns on which feeds the standby voltage to the main board. The main board starts loading its software - this usually takes about 5 seconds on newer TVs. When the software is loaded, the main board then turns on the "run" supply of the power supply. The power supply turns on and feeds the run supply (typically about 12V) back to the main. The main detects the run voltage, shuts off the power supply and goes into standby to wait for a remote signal or the power contact to be pushed.   >So if you see the "ps-on" line high and no 12V (just the standby 3.3V or 5V), the power supply is the problem, not the main. If the power supply ps-on line never goes high at any point, the main is bad or being locked up by a peripheral board.   >It seems that there are two versions of that model; one has a separate power supply and main, and the other has them on one board. So if yours is a really low end toilet, the power supply is combined with the main board, so identifying control lines is a real problem. If you have an all in one it's best to troll the internet and look for a donor.   This had one main board with power and secondary-side signal processing/communications/audio etc, with a smaller board interfacing the led strings.   The PFC section (400v boost) was enabled, with four secondary-side supplies ID'd as running (12v, 5v, 3v3, and 1v2).   UD3, marked GH6K, seemed to be the non-functioning postregulator - I assume it would supply something between 5v and 1v2, considering the lack of designer discipline in the selection of chipsb but couldn't be sure it wasn't disabled internally.   As I've said, there's no sign of parts on offer for this thing, or a manual.   RL   After a long power withdrawal, the unit could be convinced to give a single lamp burst after start-up, but this was not evident in response to soft on/off cycles. I assume that's latching protection of some sort.

John-Del <ohger1s@gmail.com>: Sep 28 02:30AM -0700 On Friday, September 27, 2019 at 4:54:50 PM UTC-4, legg wrote:   > single lamp burst after start-up, but this was not evident in response > to soft on/off cycles. I assume that's latching protection of some > sort.   Referring back to the boot/start strategy I mentioned, a very few models will also enable the backlight on briefly before the main IC decides everything is fine and go to standby mode. You may have an LED issue in the screen..   LEDs issues can be challenging. Some really cheap models use a single string of LEDs in series. Any open LED or an LED that is dropping more than it's nominal voltage (either 3V or 6V LED) will trigger either an over-voltage or under-current condition that will cause the LED driver IC to output an "alarm" to the main IC.   If you're lucky, there will be two or more channels of LED strings and hopefully they'll all contain the same amount of LEDs in each channel. If so, you can use an external tester like this one:   https://www.ebay.com/itm/New-330V-TV-LED-Backlight-Constant-Current-Board-Tester-Tool-Repair-TV-Led-Strip/392260386303?hash=item5b548a7dff:g:e-8AAOSwRFNcjO5H   Some TVs (many LGs) use a two channels system but run an odd number of LED strips for each, so comparing one channel to the other won't be of any help. One channel strings also leave no reliable reference to test against. Sometimes you just have to pull the screen and do an exploratory.   I would guess that your RCA is a two channel system using balanced strings. Disconnect the LED harness and use the LED tool to check the running voltage of both strings. If one string is open, you found your problem. If one string measures a few volts different from the other, that could also be your problem.   If you intend to work on TVs, you MUST have and LED tester. You can buy LEDs from Alibaba. I keep three types: 3V square, 6V square, and 6V "puzzle piece". You can also buy the complete strips and not have to deal with changing the individual LEDs, but this cuts into profit immensely.

legg <legg@nospam.magma.ca>: Sep 28 09:52AM -0400 On Sat, 28 Sep 2019 02:30:06 -0700 (PDT), John-Del <ohger1s@gmail.com> wrote:     >Some TVs (many LGs) use a two channels system but run an odd number of LED strips for each, so comparing one channel to the other won't be of any help. One channel strings also leave no reliable reference to test against. Sometimes you just have to pull the screen and do an exploratory.   >I would guess that your RCA is a two channel system using balanced strings. Disconnect the LED harness and use the LED tool to check the running voltage of both strings. If one string is open, you found your problem. If one string measures a few volts different from the other, that could also be your problem.   >If you intend to work on TVs, you MUST have and LED tester. You can buy LEDs from Alibaba. I keep three types: 3V square, 6V square, and 6V "puzzle piece". You can also buy the complete strips and not have to deal with changing the individual LEDs, but this cuts into profit immensely.   I'm aware of LED issues - this one didn't seem to have an identifiable power port for separate strings. The flash showed no open strings or dull areas as viewded from the rear vents - hence my suspicion re LV post regs.   The flash isn't repeated for controlled on/off sequences; only after long delayed line power applications, so this is some kind of latching hard fault.   The unit's not here any more - was in for free inspection/quote and I had to admit that it was beyond current capabilities for competent repair - no docs or spares.   Usually I can offer options, doc costs, or physical kluges to get the thing up and running etc. There are sets out there now with 3/4 strings and slightly darker areas on the edges of the screen - simply cheaper than relamping - gives owner time to consider replacement or relamping as an option, without loosing their 'TV time', in the meanwhile. For relamping, I refer them to guys who do it (and not much else) all the time.   I haven't had a TV in my own home for decades, though the computers are threatening to become/contain the same kind of rubbish.   RL

Jon Elson <elson@pico-systems.com>: Sep 27 02:15PM -0500 On Fri, 27 Sep 2019 05:16:40 -0700, mogulah wrote:     > Japan and South Korea Feud, but Breaking Up Is Hard New York Times - > August 28, 2019 -- > https://www.nytimes.com/2019/08/28/business/japan-south-korea-trade.html   Wow, they know how to hit them where it hurts! Photoresist! Yikes!   Jon

bruce2bowser@gmail.com: Sep 27 04:01PM -0700 On Friday, September 27, 2019 at 3:15:37 PM UTC-4, Jon Elson wrote: > > August 28, 2019 -- > > https://www.nytimes.com/2019/08/28/business/japan-south-korea-trade.html   > Wow, they know how to hit them where it hurts! Photoresist! Yikes!   You gotta wonder how Japan got such a corner on that stuff. A lot like China has a lock on the rare-earths, I guess.

Ralph Mowery <rmowery28146@earthlink.net>: Sep 27 07:31PM -0400 In article <00288d06-e925-4900-bebb-be87a59fa012@googlegroups.com>, bruce2bowser@gmail.com says...   > You gotta wonder how Japan got such a corner on that stuff. A lot like China has a lock on the rare-earths, I guess.   Was that Japan or another country that had some special epoxie (whatever) that was the covering for IC memory chips way back in the 1 K per chip days ?

Clifford Heath <no.spam@please.net>: Sep 28 06:17PM +1000 >>> https://www.nytimes.com/2019/08/28/business/japan-south-korea-trade.html   >> Wow, they know how to hit them where it hurts! Photoresist! Yikes!   > You gotta wonder how Japan got such a corner on that stuff. A lot like China has a lock on the rare-earths, I guess.   China doesn't have a lock on rare earths. The ores are available in many countries, including Australia. What China does more than anyone else does is *process* the ore, because the processes are incredibly polluting and they don't care about pissing in their own pool. If they ever tried to really restrict trade in rare earths you'd find plenty of countries ramping up their processing programs.   Clifford Heath

xushenghui2015@gmail.com: Sep 27 09:25PM -0700 Did you ever get a schematic because I need one for mine too. Can you send me one via email pdf sanfy@netease.com

tabbypurr@gmail.com: Sep 27 09:49AM -0700 On Friday, 27 September 2019 11:43:04 UTC+1, Fox's Mercantile wrote:   > Which is the worst possible way of using a carbon composition > type of resistor.   > Peter told you that. I told you that.   it's the worst way to use any resistor, but that is immaterial. When an EE needs a resistor with large pulse tolerance, carbon comp is the best candidate for the job, and by a long way. There's no other reason to use them nowadays, no other way in which they're better, and they certainly aren't cheaper.   Are you really claiming to not know this stuff?     NT

tabbypurr@gmail.com: Sep 27 09:51AM -0700 On Friday, 27 September 2019 12:38:39 UTC+1, Fox's Mercantile wrote:   > > Arie   > Obviously, you're using the film types incorrectly and not specifying > specifying the correct rating for the application.   Oh boy. Carbon comp is so much better at pulse work that a comp R with a given pulse rating is cheaper than a larger film type with the same pulse rating. THAT'S WHY THEY'RE USED.     NT

"pfjw@aol.com" <peterwieck33@gmail.com>: Sep 27 11:23AM -0700 Operative word being "CHEAPER".   Which is what I am getting to with the comment "kicking the can down the road".   Being that this is a hobby for me, there are very few things that I purchase in sufficient quantities that even a 100% premium (and it is nowhere near that for resistors) is not worth the extra cost for the avoidance of trouble. I just purchased a lot of electrolytic capacitors to go into tube equipment - the premium for 105 C High-Hours caps vs. standard caps came to about 5% across 20 caps in total.   Peter Wieck Melrose Park, PA

Fox's Mercantile <jdangus@att.net>: Sep 27 01:24PM -0500 >> specifying the correct rating for the application.   > Oh boy. Carbon comp is so much better at pulse work that a comp R with a given pulse rating is cheaper than a larger film type with the same pulse rating. THAT'S WHY THEY'RE USED.   > NT   Oh, that's right. I forgot you're never wrong.   Even when you are.     -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

tabbypurr@gmail.com: Sep 27 03:41PM -0700 > Operative word being "CHEAPER".   > Which is what I am getting to with the comment "kicking the can down the road".   No, modern resistors used within their specs are very reliable. They're among the most reliable of electronic components. Further comment is just not worthwhile.     NT

Fox's Mercantile <jdangus@att.net>: Sep 27 06:11PM -0500 >> Which is what I am getting to with the comment "kicking the can down the road".   > No, modern resistors used within their specs are very reliable. They're among the most reliable of electronic components. Further comment is just not worthwhile.   > NT   Yet you persist on saying carbon composition resistors are better for a given application.   Make up your mind.       -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

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