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Old 21st Oct 2021, 2:38 pm   #1
IKC2E51R8
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Default Help with Philips L01.2E Chassis Sound

Hi All

Got a 14PT2666 Philips portable with the L01.2E Chassis, nice little stereo set, one of the speakers had a bit of distortion on it so opened it up and the right speaker was worn so i soldered the speaker wires to a new speaker and i changed the left for good measure too, the set originally had 2x 4w 16Ohm speakers and I replaced with 2x 3w 8Ohm speakers (Manual indicates 3w @ 8Ohm is fine) and thought lovely... job done...not so....

Powered the set on and and briefly got very low output from the left speaker and nothing from the right, after a few seconds the right speaker tried to kick in but with heavy distortion that progressivly got louder, i switched the set to standby to prevent anything blowing and while in standby the LED was flickering rapidly with a low 'thump' noise from the speaker in unison with the LED.

Not sure whats happed as all i changed was the speaker, now it keeps doing the same thing on every power on, picture isnt affected by it at all. once the symptom begins and the set is powered off, the audio heatsink is extremly hot after being on less than a minute and the 470uf cap in front of the audio amp is getting hot too.

can anyone point me in the right direction as to whats happened and where to look?
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Old 21st Oct 2021, 2:40 pm   #2
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Default Re: Help with Philips L01.2E Chassis Sound

i should point out none of those symptoms were present before i changed the speakers, the right one just sounded a bit tired but it was running fine for an hour with none of the above symtoms
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Old 21st Oct 2021, 3:40 pm   #3
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Default Re: Help with Philips L01.2E Chassis Sound

The answer here is probably 'What have I done'. The fact that it worked OK with the original speakers directs the fault towards the speakers you have fitted.
I would suggest you replace the original good speaker testing it on both channels. You may have damaged the audio output transistors/I.C. by fitting speakers that do not suit. Just a thought. J.
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Old 21st Oct 2021, 4:50 pm   #4
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Default Re: Help with Philips L01.2E Chassis Sound

Strange that the manual states 8 Ohm when 15 Ohm speakers were fitted originally.
Was there actually a range of impedances given?

Was this the user instructions or the service manual, and was it actually referring to the internal speakers or an external speaker connection?
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Old 21st Oct 2021, 5:36 pm   #5
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Default Re: Help with Philips L01.2E Chassis Sound

Quote:
Originally Posted by Heatercathodeshort View Post
The answer here is probably 'What have I done'. The fact that it worked OK with the original speakers directs the fault towards the speakers you have fitted.
I would suggest you replace the original good speaker testing it on both channels. You may have damaged the audio output transistors/I.C. by fitting speakers that do not suit. Just a thought. J.
Also forgot to mention it's doing the same thing now with the original speakers connected, I think the IC may be damaged but can't understand how seeing as the replacement speakers are within the spec of the IC
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Old 21st Oct 2021, 5:40 pm   #6
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Default Re: Help with Philips L01.2E Chassis Sound

Quote:
Originally Posted by rambo1152 View Post
Strange that the manual states 8 Ohm when 15 Ohm speakers were fitted origanally.
Was there actually a range of impedances given?

Was this the user instructions or the service manual, and was it actually referring to the internal speakers or an external speaker connection?
The service manual states a variety of setups depending on the version, seen in the pic below but in the set was 2x 16Ohm speakers. It's referring to the Internal speakers.

If the spec allows for 2x 8Ohm speakers is there another reason for this fault? I think the IC is frieed but don't wanna buy a new IC if I don't have to, they're only 5 on eBay but still would rather not have to buy one
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Old 21st Oct 2021, 6:37 pm   #7
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Default Re: Help with Philips L01.2E Chassis Sound

The clues to why it may have damaged the IC will be in the diversity tables.

The L01 manual was notoriously complex to work out which component value and even which components were actually fitted depending on the numerous options (the components marked with a *.

Just because the manual states that there are options to fit different impedance speakers, while that is true you need to see what other components and component values were also changed simultaneously to accommodate the changes.
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Old 21st Oct 2021, 11:37 pm   #8
IKC2E51R8
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Default Re: Help with Philips L01.2E Chassis Sound

Quote:
Originally Posted by Red to black View Post
The clues to why it may have damaged the IC will be in the diversity tables.

The L01 manual was notoriously complex to work out which component value and even which components were actually fitted depending on the numerous options (the components marked with a *.

Just because the manual states that there are options to fit different impedance speakers, while that is true you need to see what other components and component values were also changed simultaneously to accommodate the changes.
After checking the manual I can't see any * that notes a different part/value based on what speakers were fitted, it only has * for if the set has side inputs or different amplifiers if it's stereo or Mono. In any event it seems the manual is wrong anyway based on the speakers that were in the set in the first place.

I'm thinking I might just buy a new IC and replace the three caps next to the IC, I've checked the SMDs connected to the IC and they seem to be fine.

I can't see anything else that could be responsible for this behaviour other than when it ran with the replacement speakers for the first time the IC didn't like it and packed in. Set won't run for more than 20 seconds now without screeching from the speakers and the LED blinking like crazy. I think there is probably an Internal short in the IC just by the way it's behaving and the Heatsink getting too hot to touch after a few seconds.
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Old 22nd Oct 2021, 5:53 pm   #9
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Default Re: Help with Philips L01.2E Chassis Sound

I'd be tempted also to find some 16 ohm speakers just in case.
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