What is this unit?

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fredje1
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What is this unit?

Post by fredje1 » Sat Nov 06, 2004 11:37 am

Hello There: I have not been too active on this net but I have a qusetion and a request.
Does anyone here know where I can download a Datasheet for a transistor that is marked 6822al on the transistor? Ther is a marking in addition to the part number which Is SI. I assume that is silinox but I may be wrong. Now I know what a transistor is but when I look at web sights that feature data sheets they say to use so and so part which is totaly diferent that the part that I have. One company says that it's a mossfet and which shows an eight pin flat pack and others show a diode and I am thourally confused. I need a data sheet that will show me if it's an NPN or PNP. The transistor looks like any ordornany 2n2222 PN2222 Mps6517 ETC. I am presently desinging a low voltage Array of lights and I want to investigate this Transistor. I found this unit is a florescent Light bulb that went out and I broke it apart and looked at the components and this transistor is in among the others. Would'nt you know the bulb was made in China By GE. anyway I would appreciate anything on this component. One more thing this unit does'nt act like any transistor that I have ever tested with an ohmeter. If you put the pos lead on the base and the neg lead on the collector you get 12 ohms and if you reverse the Leads you get 12 ohms. You get no reading if you put the neg lead on the emitter. On either tests results with no output from the emitter Thanks in advance. Chow
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Edd
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Re: What is this unit?

Post by Edd » Sat Nov 06, 2004 1:43 pm

<<<a transistor that is marked 6822al on the transistor? Ther is a marking in addition to the part number which Is SI>>>
Sure sounds like only a house number..as the suffix number is higher than any common/ familiar JEDEC or JIA designator being used .
<<<I found this unit is a florescent Light bulb that went out and I broke it apart and looked at the components and this transistor is in among the others.>>>
Assuming “in” a fluorescent fixture….and probably just a small 3-5 watt tube [ possibly bent into a “U” mechanical layout] that is being fed. Probably no IC’s in its construction either, possibly just a simple power oscillator circuit with that semi unit being the final HV inverter transformers driver.
<<<If you put the pos lead on the base and the neg lead on the collector you get 12 ohms and if you reverse the Leads you get 12 ohms. You get no reading if you put the neg lead on the emitter.>>>
If the device was the power driver and subjected to very high current drain I would expect it to have popped open its internal emitter die connector link. Also how about confirming as to whether that ohm out was with the device in or out of circuit. If in circuit, float the C & B leads and check again. I would tend to expect that reading to be shunt circuitry reading. Commonly an opened emitter junction semi will have have its C-B junction avalanched into a short. <p>Lastly, no chance that this unit is the small palm sized reading lamp unit marketed by Radio Shack ? As I have got a few of them off their 99 cent table and repaired them.<p>73's de Edd
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Re: What is this unit?

Post by fredje1 » Mon Nov 08, 2004 10:55 am

Thank's ED for your insight. I took this transistor out of a light bulb that was made by GE in China and I took the liberty of tracing out the circuit and found that two of them are used in an inverter circuit. I tested both transistors in and out of the circuit and they both read 12 ohms in either direction. Could be as you said the e/c junction blew but in both transistors???????? It's not unheard of but one has to think a little closer on the coincidence involving two matched pairs going bad at the same time. Usually one or the other but not both in this type of circuit. Anyway I have a circuit to see what's going on. I haven't done anything in the way of replacement as I have yet to determine which is best fitted to the circuit NPN or PNP. Q1's emitter is fed through a 2 ohm resistor from the negative supply and Q2's colloctor is fed from the positive of a full wave bridge rectifier. It looks like a push pull circuit but if it is its sure a strange way of designing a Push Pull. I can't undestand why I can't find a data sheet on this transistor in any of the download datasheet directories. Anyway thank's for the information and I will get back to you with my findings. Chow & 73's .fredje1
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Chris Smith
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Re: What is this unit?

Post by Chris Smith » Mon Nov 08, 2004 11:13 am

Most Fluros of modern day style use Fet chopper circuits. In the old day transistors were used, but they consumed way too much current and ran hot enough to boil water. <p> A "on type" or "Shut off Fet" Fet might account for the on resistance in both directions in the powered down or off mode, as they require a voltage to turn the gate off. <p>Often called gate shut or turn off Fets.

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Re: What is this unit?

Post by Edd » Mon Nov 08, 2004 12:25 pm

Totally in agreement on the coincidence statement, but I was savvy only on your initial info as only one transistor being in that condition..
<<<<two matched pairs going bad at the same>>>>>….One matched pair?....
Exactly how many components are there in the primary circuit, especially the semiconductors, also how about the transformer windings. Knowing that there is the secondary HV winding for feeding the lamp.
Considering the primary , a question would be is if the two power semis have their individual primary windings , or are they fed by a single center tapped primary winding ?. Also , are any additional winding(s) providing a feedback loop , if this is merely a 2 semi power osc ckt?<p>Also on the whole lamp device proper, any idea of its age , Manufacturer and , also if any numerical code dates are on any parts<p>The only switcher/chopper products that I remember that might vaguely resemble Chris’ s reference would be
gate turn off SCR/thyristors by NEC et al and were in hockey puck sizes, with the smallest I ever run across being a Sony in a TO-66 casing…..nowhere the small sizing of your referenced TO-92 housing….and boy were they pricey.<p>73's de Edd
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Re: What is this unit?

Post by fredje1 » Mon Nov 08, 2004 2:36 pm

Now that I got some attention maybe you guys can shed some light on this project. First of all the transformer that is used for the chopper is a small doughnut about 3/8 inch diameter and has three windings. Accordion to the circuit that I drew up the primary feeds one side of both sections of the lamp and the other side through two .047 uf cap from each tube to the Positive side of the Bridge rectifier. From the bottem end of the primary theres a coil which feeds the two lamps in parellel. I think Chris is rite but one thing that I don't understand is if these are fets wouldn't they be labeled as source drain and gate, but they are not the board is silk screened and have EBC very strange. The case is of the To 90 as the pn2222 and mps versions of the plastic coating. The two secondaries are connected in this manner, one secondary, the top of the winding goes to the emmiter of Q2 through a 2 ohnm resistor and the bottem end goes through a 10 ohm resistor to the base and the collector goes back to the primary Pin one. The other secondary top windiing goes through a 2 ohm resistor to the emmiter of Q1 and the bottem goes through a resistor to the base and the bottem of the winding goes to the top of the primary winding The collector goes directly to the Posotive side of the bridge rectifier. If you would like to see the diagram tell me how I can put it on the web other than that I Can only tell you that I can't figure this out. Thank's Chris and Ed. Chow & 73's fje
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Chris Smith
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Re: What is this unit?

Post by Chris Smith » Mon Nov 08, 2004 5:42 pm

Is this fluro 12 volts or 120 volt driven?
Yes a diagram would help.
120 volt driven would mean a TO92 size fet would be more than adequate, at 15 watts. <p>
Ed,... turn off gate SCRs like my Sony had on the deflection ?yoke? 20 years back were To220 size, and even then could hold gobs of amps and HV,.... while FETS have come a long way since and have replaced just about every Transistor and their applications at far less consumption. <p>Some signal FETs even in the 60s were TO92 size in most car radios, and so Turn off gate type FETs like everything else have met all size requirement and replacement values since then. <p>Also boards are often mismarked, with the EBC instead of GDC as FETs can be substituted for Transistors with little fan fare in some cases.

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Re: What is this unit?

Post by fredje1 » Tue Nov 09, 2004 5:43 am

Hello Chris:
Thank's For the info and to answer your question the input is 120 volts AC to the brigde and 167 or so volts DC out and the supposedly transistors or fets have 70 or so volts on one of them and 160 volts on the other. That is on the drain or collectors. You may be correct in that they are Fets with a mismarked screening. In any case I put 120 volts in and that was the reading that I got. It's hard to find HV fets that are of the TO92 type anymore. I guess I'll have to check Digikey or Nec or Toshiba or Sharp or anybody that will have them. Thanks for the insight, I have'nt worked on TV since the late 80's. As far as television goes my work spans over 50 years. I started in 1935 with a radio that I had built up and tested it and from there about the late 1946 my Television experence began. It was relitivy new and not yet hit the market till the late 47's. I used to work for Applied Research in California which we were producing Spectro Graphic Anylizers, You know the kind where you shoot an HV to a peice of material and read the angle degree of light that was emmited which would tell you what chemicals were contained. Then I went to Kennedy Electronics In Altedena California and was a test technician and later worked with the boss Chuck Kennedy in the Engineering Department for 4 years at which time I had mooved back to Ma. and started my Business as a Tv & Radio repair which carried on for 10 years+. When 1980 rolled around I saw which way the wind was blowing and decided that it was time to pull Plug and find something else to do. Televisions became so cheep that the coustomer would'nt have it repaired. They decided to buy another, Also since the birth of transistors and less and less tubes were installed it was useless to have an old set repaired unless you wanted to keep it for a souvineer. Besides the sets that had these transistors and fet's were more dependable and lasted for the life of the Picture tube or CRT as we know in the Engineering field. Geese I Didnt mean to write a novel but I wanted you to know that I wasn't a slouch in Electronics. I have been in Engineering for over 15 years and worked up to an Engineering Position with Mekle Engineering in Covina California as an Engineer and we were disigning High speed cameras and Simulators for the Army. That only lasted for several years till the company mooved and broke the bank resulting in the company going out of business. I have worked with the best of them and am very proud of it. My Electronics spans over 5 decades and I have seen just about every form of component that was made up till I went out of business and then I relaxed and now I am retired and loving It but I miss the Paycheck. I am still keeping my hand in designing and tinkering to keep my mind active. Thank's for all the Info and will try to be on the net more often. Chow and 73's fje
PS: If you send me your Email Address I'll send you a copy of the schematic and also the board Artwork that I drew up. And you can see if I made a mistake in the drawing Which would be greatly appreciated.
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Re: What is this unit?

Post by Edd » Mon Nov 22, 2004 2:02 am

fredje...ichi ban:
Your query on the lamps component info made me think of my having built an above sink lighting source for the sink work area in our kitchen. Encasing is provided within an 38"W x 12"D x 4"Hi red oak plywood case with a bottom clear prismatic plastic sheet. Its lighting source being 4 compact fluorescent lamps mounted centrally and equi-interspaced. The prior single 60 W incandescant fixture is now replaced with this new arrangement with an ~ 100 W power consumption, but with an equivalent luminance output of ~ 400 W incandescant lamps light output . (In accordance with the variances in efficiency, as touted by different fluorescent manufacturers)
It seems that I had initially run across these fluorescent lamps in a Dollar store. I initially got 2 units for use in a tandem fixture in the bath, but eventually had found both of them failing within < 6months of use. One unit had failed with a BANG, with its venting of an internal electrolytic capacitor in its power supply, whilst the other unit failed with ion burns developing on its fluorescent tube ends and an eventual flickering and loss of luminance output. I just cast the failures aside, with them only having been 99 cent expenditures, whereas normally, these units seem to have currently discounted down into the $4-5-7 range .
Months later I happen to have been at the same store looking for other unrelated items and coincidently noticed the items now being in a much flashier blisterpacking ….this being because it was another manufacturers product. Pulling aside and conversing with the store manager revealed that he had sort of experienced a caveat emptor situation with his distributor on his failed stock and thereby found a different sourcing for replacement stock. He was somewhat surprised with my tech info that I had told him on the initial units manners of failure, so much that when I purchased two of the new units to evaluate, that he went to the storeroom and pulled out 6 of the old units, and better yet, two of the newer brand of units that had been returned to him by customers. No problem in making of failure analysis of the new units, the customers had gripped the unit by the tubes when twisting them into the AC socket, and in the final torque, cracked the tubes. (Proper installation procedure being to grip down at the units BASE). So,in the end, I am walking out with 2 units for two bux plus 8 freebie "parts" units.
Now the other coincidence here was the situation of having our facilities maintenance using many, many of the energy saving compact fluorescent lamp units thru the plant, with most fixtures using but a sole tube, but in some desk workstations, a trio of the lamps were utilized. To have an aesthetically appealing balanced light output at those fixtures, the whole trio was usually changed out simultaneously, with the old trio being saved, possibly to later be utilized individually in single lamp applications. I was offered several of those used lamps and, naturally, I fired up and cherry picked out ~ 8 units exhibiting neither end terminal ion burns nor any undue graying out of the white phospor coating.
The used lamps were Sylvania brand, 26 Watt rating and in the 4 pin Dulux lamp profile design, initiated by the Osram line of lamps. That lamps profile folds into a very tight rectangular wedge U bend with two U units being mechanically co-joined into a rectangle, producing 4 light radiating surfaces.
Contrastingly, the lamp profile of the 99 cent units was using three distinct soft U bend sections offset 120 degrees from each other, yielding 6 light surfaces. The big fallacy with the latter lamps was their reliability, with starts of ion burns already being visible on new units as well as them showing certain areas of skimpy, non uniform phospor coatings. Also I saw ratings of 18-20-22 watts...marked on different units....probably, just the culling out of different degrees of mediocricity! I will give them one fabrication credit though, and that was the lamps filaments , some fine looking thoriated tungsten wound in a triple helix fashion. [Thats where the fine tungsten wire is initially tightly coiled to the wires minimun turning radius , slightly pulled lengthwise to space/insulate the individual turns and the the resultant new wire coil is used as "wire" to wind another coil in the same manner].Maximum surface area for electron emissivity, being the desired end result. A length is then used in fabricating a 1 1/2 turn loop between the fil beam support wires, with a final crimp and spotting of those two connections.
The shortcomings of the 99 cent units certainly seem to be in their lamp tube elements quality and also their potential electrolytic filter cap failures, otherwise the units PCB's are well built . I made sure that their initial fallacies were negated when re using the same electronics ballast PCB's, by using more robust 47ufd/200vdc 105deg rated power supply electrolytics installed in place of the 4.7 ufd stock units. . Also, the supplied lamp tubes were pulled and replaced with the Sylvania lamp units. Individual one inch lengths of 3/4 in dia solid Lucite rod stock, tapped at both ends for nylon screws, served for standoff insulative mounts for the 4 individual PCB's and lamp tubes to affix to the cases topside. AC power was daisy chained betwixt the individual units with an additional incorporation of 4 pigtail fuses. That refined light fixture has been flooding out an abundantly bright white lighting for upwards of ~ 9 months now.<p>One of the newer brands of lamp PCB's and its electronic components were examined , as one thing in particular I remembered was also noticing a toroid being incorporated in their design. I reverse engineered the schematic below from examining a PCB and rubber banded it around to produce a logical schematic layout.<p>I believe that some degrees of commonality / if not identicality with your described unit are probable.
• 1...Very few turns on the toroid (4t+4t+8t) but you had no mention of a MULTI turn HV secondary inductor, which is placed just off center on the PCB, however yours might have been hidden within a plastic housing.
• 2...The two TO-92 encased devices may have the same manufacturer logo marking. A 25x magnified closeup examination of the symbolization revealed it having been done with power laser etching, with the first symbol being a stylized capital S, much in the order of a reversed capital Z with the corner apexes being slightly rounded. The second logo letter is a right sloped small i, the laser power stroke starts up from the bottom and pulse power width was dropped at the top portion of the small i and then resumed again to dot the i, leaving a subdued channeling in the low power traced (skipped) area. See if your xstrs marking might be the same.
The semiconductors are Shenghai Industries units # Si13001, of conventional Hi voltage NPN bipolar design...in a TO-92 casing...nothing in the order of a HV pwr FET..nor exotic gate turn off SCR types of devices. Basing layout ..top flat index referenced is...ECB. A pulling of 2 units and running a curve tracing of their specs reveals an avalanche BvCEO of 525vdc on one unit and 500vdc on the other. Some healthy V spec margins, considering that they are then used in a series totem pole configuration in their circuitry. Their Betas checked out as 20 and 22…not abnormal on HV units.
The power supply uses a voltage doubler circuit with its ends feeding across the totem pole series transistors with the initial power application initiating a capacitance kick at the base of the lower xstr to shock the unit into imbalance and the feedback from the toroids pink and blue windings, alternatively, then initiates sustainable oscillation. The two top half inductive elements are arranged in an autotransformer configuration so that the high voltage, for the ionization of the fluorescent lamp, is produced. Initially however, the high voltage just sees an open circuit between the lamps opposing electrodes. The coils designed inductive Z as well as the series capacitors Z's are of such value as to complete a path thru the .0022 cap and initiate a warming up of the filaments and building up of electron emission to the point where the high voltage can then initiate an ionization of the gas/mercury/combination fill to create a sustained plasma discharge between the electrodes, with that then being the less resistive path , and a drop out/diversion away from the initial. .O022 cap start up path.<p>;) ;)<p>[ November 22, 2004: Message edited by: Edd Whatley ]</p>

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Chris Smith
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Re: What is this unit?

Post by Chris Smith » Mon Nov 22, 2004 8:59 am

Yes it was a KV model and I could look, but I think it was the KV1920. The SCR was only 10 bucks back then, and it worked. Pretty good guess work considering it was My First TV repair, diagnosis, and all with out any formal education or trainng in TVs!<p> Yeah it was back in 77-78 when I bought it, and I repaired it just a few years after that. Still have it holding up the table in the work shop, I think? Nice wood case.

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