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 Post subject: Telefunken Allegro Stereo 205 Stereo Output Issues
PostPosted: Sep Sat 11, 2010 9:27 pm 
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Joined: Jan Tue 12, 2010 9:01 pm
Posts: 72
Location: Middletown Ct
Hi guys I have a telefunken Allegro Solid State Stereo model 204 thats been changed to a rca jack system from german din jack system on the back where the speakers hook up,that seemed to go together ok,made a plate to attach the plate mounted rca jacks to it soildered the wires to rca jacks,closed the back plugged the speakers in,made sure the balance was right,got it all hooked up,it only plays on one side loudly,the other channel is there but has far less volume then on the other side,any ideas whats going on,is it the balance control knob or a output stage or transformer ,wire,resistors,the speakers and the output from the set is 4 ohms and 25 watts too,maybe its dirty,what should I try or check.


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PostPosted: Sep Sat 11, 2010 10:05 pm 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
Posts: 34328
Location: Sandpoint, IDAHO 83864
First of all, try swapping the speakers. Plug the left one into the right jack and the right speaker into the left jack and see if their is any difference. Sometimes those RCA plugs and Jacks don't quite make connection like they should.
Curt

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Curt, N7AH
(Connoisseur of the cold 807) CW forever!


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 Post subject: Telefunken Allegro Stereo 205 Stereo Output Issues
PostPosted: Sep Sat 11, 2010 10:21 pm 
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Joined: Jan Tue 12, 2010 9:01 pm
Posts: 72
Location: Middletown Ct
Curt,
Thanks but, problem stays with amp channel. Speaker swap causes problem swap. Left was low volume, swap causes right speaker to be low.

Thanks Dan


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 Post subject:
PostPosted: Sep Sat 11, 2010 10:31 pm 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
Posts: 34328
Location: Sandpoint, IDAHO 83864
Next thing I would check is the wiring to the jacks on the set. There is considerable power flowing to the speakers and a bad solder joint can raise havoc. Also a partially shorted jack will do the same thing.
Curt

_________________
Curt, N7AH
(Connoisseur of the cold 807) CW forever!


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 Post subject:
PostPosted: Sep Sat 11, 2010 10:33 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 15481
Location: Utica, NY 13502 (USA)
If it worked before you made the change, I'd suspect a wiring error or a short.

Dave


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 Post subject: telefunken Allegro Stereo 205 Stereo Output Issues
PostPosted: Sep Sat 11, 2010 10:41 pm 
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Joined: Jan Tue 12, 2010 9:01 pm
Posts: 72
Location: Middletown Ct
Thanks for the help,we will try it and see what happens,we will take a close look at the wiring,connections etc. Thanks Dan


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 Post subject: Telefunken Allegro Stereo 205 Stereo Output Issues
PostPosted: Sep Sun 12, 2010 8:26 pm 
Member

Joined: Jan Tue 12, 2010 9:01 pm
Posts: 72
Location: Middletown Ct
Hi guys looked at all my connections,they look fine everything is hooked up right,no soidler bridges nothing is hooked up bad,even cleaned the switches everything is good,does anybody know where to get a schematic for this set,can't find one anywhere,its looking more and more electronic in nature,almost like theres resistance holding back that channel or something bit the dust,lol.Any Ideas


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 Post subject:
PostPosted: Sep Sun 12, 2010 11:41 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 4294
Location: USA
If it's only lower volume and not distorted, could be a bad resistor or cap or a problem in the pre-amp. Usually if a driver or output goes bad, there will be some or a lot of distortion. It can still be speaker switches or other controls acting up or still dirty.

Time to do some sleuthing for bad parts with the ohm-meter or try some signal tracing.

In many stereo amps, there's a certain symmetry between the two channels. Since one channel works, you can look for the same types of parts for left and right sides and compare voltage or resistance readings.

-Ed


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 Post subject: telefunken Allegro Stereo 205 Stereo Output Issues
PostPosted: Sep Sun 12, 2010 11:58 pm 
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Joined: Jan Tue 12, 2010 9:01 pm
Posts: 72
Location: Middletown Ct
Thanks for the info,not sure how to do all that,don't have the equipment except a voltmeter,not sure how to proceed with testing it should I seek a radio repairguy.


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