[TechAssist] Re: Aiwa ADV58u amplifier-tuner , no sound

  • From: larry <schntv@xxxxxxxxxxxx>
  • To: techassist@xxxxxxxxxxxxx
  • Date: Tue, 30 Nov 2004 14:31:08 -0500

this is weird,
the message i posted has a sign file on it, but it is gray 
instead of black print.
but when you reply it is gone completely.
can anyone explain this?
i am using Mozilla.
well any way, We are Schneider tv
dover ohio.

i just cut and pasted this from my earlier sign file.

Schneider TV & Electronic Inc.
5415 N. Wooster ave.
Dover, Ohio 44622       www.geocities.com/schntv2000/
330-343-0768         FCC. first class & Extra class K8WLY
  maybe it will show up now.
Larry


becyn wrote:
> Well, larry...
> Still no sig file???? why don't you just type it in until you get the 
> thing to do it automatically,...or ...well...you know the rules...;-)
> 
> Sincerely,
> See sig file below!
> 
> Jim McVey
> McVey Alltronix   
> 327 Broadway
> Newburgh N.Y. 12550
> 
> Factory authorized
> service for over 20
> major brands.
> 845 561 8383
> 
> 
> 
> larry wrote:
> 
> 
>>thank you again, jim.
>>good question, why isnt my name and address at the bottom.
>>i dont know
>>it was on the original i sent.
>>i checked and my signature file is supposed to be at the very 
>>bottom.
>>so i hope it works this time.
>>Now on the stereo.
>>i am slowly learning, i think.
>>i was confused on which ground to use for the voltage 
>>measurements, but now think i got it.
>>on all 5 push/pull 2 transistor output circuits, i read the 
>>same voltages, -22 on one collector and +23 on the other 
>>collector and zero volts on the junction of the 2 emitter 
>>resistors for each of the 5 sets of outputs.
>>so , in my opinion i see nothing wrong there.
>>also no ohm meter shorts between the output transistor pins of 
>>any of the 10 output transistors.
>>the tuning meter shows signal, but no audio on any of the 5 
>>output channels.
>>what do i check next??
>>Larry
>>
>>
>>
>>becyn wrote:
>> 
>>
>>
>>>the relay has nothing to do with the voltages seen  on the amp board. it 
>>>only disconnects/connects  the  the amp output to the speaker terminals. 
>>>( By the way you dont need any loads hooked up to start the process) DO 
>>>NOT UNDER ANY CIRCUMSTANCES  ENGAGE THE PROTECT RELAY IF LOADS ARE 
>>>ATTACTCHED!!!!! This will damgage the loads and do furher damage (ie; 
>>>smoke, flame) to the amp
>>>
>>>I dont understand what you mean by "no voltage on the junctions". You 
>>>mean that literally? As in  no Vcc or Vee or just no offset at the 
>>>emitter swamping resistors? (low ohm ceramics)?
>>>Perhaps it's as simple as open fuses in the power supply?
>>>You need to be very precise in describing the voltages otherwise I can't 
>>>make head nor tails of it.
>>>A normal fail mode is : 1) unit powers up, but no audio out
>>>                                  2) all voltages present at amp and 
>>>everywhere else, but  a DC offset of 1volt or more can be measured at 
>>>the power amp's output  connection. (you must measure it at the pcb)
>>>You might have something else, especially if you really don't see ANY 
>>>voltages at the amp, but you're gonna have to do some 
>>>troubleshooting...or send it to ME for repair!! ;-)
>>>By the way, whats your company name and address?  I'm surprised that 
>>>Jeff didn't get on you about this!
>>>
>>>Jim McVey
>>>McVey Alltronix   
>>>327 Broadway
>>>Newburgh N.Y. 12550
>>>
>>>Factory authorized
>>>service for over 20
>>>major brands.
>>>845 561 8383
>>>
>>>larry wrote:
>>>
>>>
>>>   
>>>
>>>
>>>>thank you for the advice.
>>>>I do mostly tv repair but fix a few audio, now and then.
>>>>most the time i can check the collectors and find a short or 
>>>>see burnt resistors.
>>>>but this time none of the 5 output transistors have a short 
>>>>and no burnt resistors.
>>>>i have no voltage on the junctions of the transistors, where 
>>>>the outputs are connected.
>>>>but i doubt i would, because the relay never closes.
>>>>the power supply has normal voltage to the relay.
>>>>i am afraid to manually close the relay.
>>>>what is my next step?
>>>>Thank you,
>>>>Larry
>>>>
>>>>
>>>>
>>>>
>>>>becyn wrote:
>>>>
>>>>
>>>>
>>>>     
>>>>
>>>>
>>>>>Are amps new to you?
>>>>>IF you have voltages and no output, the thing is in protect mode which 
>>>>>kicks in if a dc voltage is dectected on the amp out node. Otherwise, 
>>>>>the speaker would burst into flames-(not good ;-)
>>>>>
>>>>>No doubt one (or more)  of the amps have a dc offset caused by shorted 
>>>>>output transistor, drivers or problem with the differential amp. happy 
>>>>>hunting...
>>>>>
>>>>>Jim McVey
>>>>>McVey Alltronix   
>>>>>327 Broadway
>>>>>Newburgh N.Y. 12550
>>>>>
>>>>>Factory authorized
>>>>>service for over 20
>>>>>major brands.
>>>>>845 561 8383
>>>>>
>>>>>larry wrote:
>>>>>
>>>>>
>>>>> 
>>>>>
>>>>>
>>>>>       
>>>>>
>>>>>
>>>>>>the readout lites, tunes stations, but no sound.
>>>>>>please , any clues where to start?
>>>>>>I have plus and minus 45 volts and also 23 volt + and -.
>>>>>>Larry
>>>>>>
>>>>>>
>>>>>>
>>>>>>   
>>>>>>
>>>>>>         
>>>>>>
>>>>>
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>>>>>       
>>>>>
>>>>
>>>>     
>>>>
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>> 
>>
> 
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-- 
Schneider TV & Electronic Inc.
5415 N. Wooster ave.
Dover, Ohio 44622       www.geocities.com/schntv2000/
330-343-0768         FCC. first class & Extra class K8WLY

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