Televison & Video Logo

Related Topics:

Question about Philips TP3281C TV

1 Answer

Philips tp3281c chasis#32d700-7570

How can I test the horizontal output transistor of this set with a simple multimeter?

Posted by pamminger on

  • pamminger Aug 30, 2007

    The H.O.T has 3 pins. I assume that from left to right, the first pin is (B)the base. The middle pin is (C)the collector, and the last pin on the right is (E) the emitter. I first tested the H.O.T. using the analog MM in a 10 ohm setting. There can only be 6 combinations with the test readings as follows where continuity = 0 or some measurable ohms of resistance; no continuity = infinite resistance:
    Red lead of mm to B, Black lead of mm to C; the reading is no continuity
    Black lead of mm to B, Red lead of mm to C; the reading is + continuity
    Red lead of mm to B, Black lead of mm to E; the reading is +continuity
    Black lead of mm to B, Red lead of mm to E; the reading is +continuity
    Red lead of mm to C, Black lead of mm to E; the reading is + continuity
    Black lead of mm to C, Red lead of mm to E; the reading is no continuity
    Next the six various combinations were then tested with a digital MM set into the diode testing mode where non-touching leads display a reading of 1 and when the leads are touching the device reads 0:
    Red lead of dmm to B, Black lead of dmm to C; the reading is .426
    Black lead of dmm to B, Red lead of dmm to C; the reading is 1
    Red lead of dmm to B, Black lead of dmm to E; the reading is 0
    Black lead of dmm to B, Red lead of dmm to E; the reading is 0
    Red lead of dmm to C, Black lead of dmm to E; the reading is 1
    Black lead of dmm to C, Red lead of dmm to E; the reading is .426

    I am not sure exactly what these results represent! Based on the above test results, is the H.O.T. is good or bad? Would appreciate any feed back.

    Thanks, peter


1 Answer


  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert who has answered 1,000 questions.

  • Master
  • 1,153 Answers

I believe this set has a horizontal output that has a damper diode inside. you can check inset or out, most popular is out set. take multimeter and put on ohms or continuity and touch each leg by holding one lead to end and if you are looking for a short then in continuity it will beep or zero or very ohms. And Ohms just the same way. looking for low ohms like 1.0 or 0.9 or anything close. Switching leggs back and forth. If all three legs are shorted then replace. but in this one 2 can be shorted and still be good, just depends on which ones

Posted on Aug 29, 2007

Add Your Answer


Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:


Am I testing this horizontal output transistor correctly?

Check the resistance between collector and emitter. It should never be Zero Ohms.

I loss the horisontal regulator of my philips tv with 25pt463a/7ir model

You are talking about the horizontal output transistor damage I assumes and post this solution. If LOT has internal winding short, the horizontal output transistor will get shorted. It will be best to replace the horizontal output transistor, alongwith the LOT

Will not come on. light blinks 6 times

Six blinks denotes the absense of horizontal sweep. Check the horizontal output transistor, whcih can be located very near to the LOT [Line Output Transformer]; for short. If it is shorted, LOT must be suspected. Replace the line output transistor with a new one, and switch ON the tv for a short period of time, say 6 seconds or so, and check the heat of the replaced transistor. If it overheats within this time, be sure that LOT is damaged; shorted inside; and should be replaced with same type and number. If a digital multimeter which can measure frequency is available, take the frequency at the collector of the horizontal driver transistor. It should come around 15525Hz. If not replace the jungle IC. OK.

Power ok but not eht function


If you have tested the secondary section of the SMPS power supply of your Sony TV, amd found it OK I thinks, and posts this solution.

If the secondary supply rail 125VDC is found ok, just goto to the Horizontal Output Transformer, a small transformer diretly soldered on tho the main board, very near to the Line Output Transformer [LOT], and its secondary winding is connected to the base of the line output transistor, which in turn drives the LOT said above, generates EHT you described.
The base of the line output transitor must get appropriate frequency to switch on and off. This frequenct is gerally comes to 15625Hz. Just measure the voltage across the primary winding of the above said line driver transformer, which can be a possiblity open winding. Check the voltage at the collector point of the line drive transitor connected ti the one end of the primary winding is easy. Then check the voltage at the other end of that winding. There must be a little difference of 2VDC or so, if the line drive section is working, and fault is after that section, that is line output section. If you have a digital multimeter capable of measuring frequency, measure the frequency of the collector point of line drive transtor, and find out whether there is 15625Hz or near to this frequency comming out. Never touch the multimeter prob to the collector of Horizontal Outout Transistor, while it is working. Your meter will get damaged.
Line output section, contains tha LOT said above and line output transitor. If the Line Output Transistor has some sort of leak, normally collector to base leak, it will not drive the LOT to produce EHT and it wlii heat up also.
Just check it heat effect, after switching the set on for a short period of time, say 30 seconds ro so. If it heats up abnormally, suspect the line output transistor and LOT. You just replace the line output transistor first, with same type and number. If it doesn't retify your problem, LOT said abve is faulty, and it also should be replaced with same type and number.
If you have to replace the horizontal output transistor, and the LOT said abve, insist on orginal, and not replace it with a susbstityution, as these are critical components in all TVs..
If you need further assistance, get me through Fixya, and be free to conact me. Ok

Philips magnavox 60" rear projection no sound no picture

That could be from

1) Faulty Lamp
2) Vertical/Horizontal Output IC
3) A Shorted IC driver
4) Blown fuse
5) Open resistors around the fuse

Keep all of these in mind and I would test the IC's first with a multimeter,IC's are transistors,usually having 3 legs and screwed into a heat sink,if they read 0 they are shorted. Also if you find something has gone bad,look around the component to see if there is an underlying problem as it will be frustrating and more expensive to find out after the first replacement.


Hello valexandrur,

You are in the correct section, now your problem may be a shorted Integrated High Voltage Transformer (IHVT) also called a Fly-back Transformer and or a shorted Horizontal Output Transistor (HOT). I would first check the Transistor to see if it is shorted between the emitter and collector (to do this use a multimeter set to "Rx1") and the reading between the emitter and collector should be near infinite no reading, if the reading is 000 ohms then the transistor is shorted and should be replaced. Now for the hard part, you technically can not check for shorted transformer turns in the IHVT using a multimeter, you will have to use a device which will allow you to do what is called a ring test. If you do not have this piece of equipment (IHVT tester), I would replace the IHVT just as a matter of good measure, since the HOT had drawn a lot of current I would assume that the IHVT was damaged to since it is in the serial path between the collector of the transistor and the VCC supply.

I hope this helps,

Thank you,


Horizontal Output Transistor

This philips board give many problems with no raster. Most times its Horizontal and sometimes it transformers I have found it would be much simple to buy board or send off to be repaired. Pts 1800-844-7871 is the best bet. You also can get hot at places like MCMelectronics, bluestar international, tritronics. If you do not want to buy board.

RCA F27669 27"

The F27669 uses the CTC203 series chassis. The most common cause of that symptom is a shorted horizontal output transistor, caused by a cracked solder joint on a small coil connected to that transistor's base. When this happens, the main B+ supply is shorted to ground so the power supply squeels. Every once in a while I also see the horizontal output transistor shorted due to a shorted flyback (high voltage) transformer. A good tech will replace the horizontal output transistor, resolder the coil and drive transformer, test the flyback (replacing it if necessary) and your set will be back to perfect.

TV Buzzing

What is it your looking for my friend. Im sorry I do not understand the way you asked the ? If ita the location of the horizontal output transistor. Its Q1401 but thats not your only problem 100% !!
Not finding what you are looking for?


Ask a Question

Usually answered in minutes!

Top Philips Televison & Video Experts

matt martin
matt martin

Level 3 Expert

1259 Answers

Jaime Hernandez

Level 3 Expert

2351 Answers

Cindy Wells

Level 3 Expert

6648 Answers

Are you a Philips Televison and Video Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides