Good evening in here.
I got a DUX dx66k 535/00, it is inside a Philips K9, as we know is in many variations.
This one is in fine condition, i found that those two capacitors around the EHT transformer is goint to be replaced soon, but that isn't the problem right now, I turn the power on to it (ca 180volt) and there is only some tickering in the speaker, I soldered the C/E off to the line BU transistor and use a 60 watt/230v bulb instead for checking the power supply works, and it is still the same fault.
I try seperately connecting the bulb to the power supply, no changes, I can see on a oscilloscope there is a small HF signal to the switch transistor, it seems it try to start up, but there is something going wrong, i measured all transistors and diodes, nothing wrong, so i think it could e the little circuit board inside the alu can.
Does somebody have some experience with this chassis?, I have never seen that fault before, it used to have bad soldering, maybe a defect line transformer.
If anyone fancies helping Alex with this fault, the K9 service manual is in the data library
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My first thought would be dry joints, or possibly tired and leaky electrolytic capacitors in the PSU as a general start upon the fault-finding journey.
Oh, and a handsome set it is if I may say so. ?
To understand the black art of electronics is to understand witchcraft. Andrew.
Hi Alex,
I have never seen a K9 chassis so probably of little help.
One item I noted was your voltage reading of 180 volts, if this is the HT line, the manual states 155 volts. If my assumption is correct then the over volts protection circuit would work and could be the ticking noise you hear. Try adjusting the HT line for 155 volts.
Frank
Hi Chris.
i can´t find the serv ice manual in the libary, hmm actually i can´t find the libary 🙁
Hi Alex,
I have never seen a K9 chassis so probably of little help.
One item I noted was your voltage reading of 180 volts, if this is the HT line, the manual states 155 volts. If my assumption is correct then the over volts protection circuit would work and could be the ticking noise you hear. Try adjusting the HT line for 155 volts.
Hi Nuvistor.
The 180 volt is feeding to the main plug, the power supply should be able to starts up with 180ac Volt,
I was yesterday out and visit a guy wh have a electronic scrabble yeard of old televisions and other electronic stuff, and i found some pair of old K9 and 11 power supply´s, and get them home, the TV is now running with one of those old supply´s, but that isn´t the right solution, so a service manual is in my wish 😉
Alex 🙂
Ok, well it did appear to be a PSU fault even if I misunderstood the voltage readings.
Frank
