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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 27th Feb 2020, 3:08 pm   #21
technotel
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Default Re: Dynatron SRX20

DMcMahon sorry for missing your reply and thanks. I have not disconnected anything yet but isn't de selecting FM button which effectively cuts the 15.4v supply to the FM stage, the same thing? I have all the components now fro cpc and will pull out old to test. I will get back with what I findings
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Old 27th Feb 2020, 3:12 pm   #22
technotel
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Default Re: Dynatron SRX20

Quote:
Originally Posted by DMcMahon View Post
I see previously people have provided you with various pages from the Service Manual, do you have the complete manual ?
DMcMahon yes lots of good literature here but nothing on the cassette deck. I have issues here as well, trying to find out what wattage the blown vu lamps are for a start and left ch playback lower volume Than right ch.
regards
technotel
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Old 27th Feb 2020, 3:37 pm   #23
ms660
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Default Re: Dynatron SRX20

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Originally Posted by technotel View Post
Also re no FM. I have discovered that there is no 15.4volts that feeds the FM stage. further investigation reveals that TR261 has no emitter volts. readings on the transistor is B=15.77v E= 0v C= 27.26v
That would suggest that the transistors base-emitter junction is open circuit, if that's the case check for shorts on the 15.4 volt rail before replacing it, just in case.

Lawrence.
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Old 27th Feb 2020, 4:06 pm   #24
DMcMahon
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Default Re: Dynatron SRX20

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Originally Posted by technotel View Post
DMcMahon sorry for missing your reply and thanks. I have not disconnected anything yet but isn't de selecting FM button which effectively cuts the 15.4v supply to the FM stage, the same thing? I have all the components now fro cpc and will pull out old to test. I will get back with what I findings
I had only replied after seeing your post in your other thread (had not seen this thread before) that you had not had any responses to your problem questions.
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Old 29th Feb 2020, 1:41 pm   #25
technotel
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Default Re: Dynatron SRX20

update
FM working now. Found TR261 found to be completely open circuit, no meter reading at any junction. Replaced with BC140-16 Data sheet says its a replacement for the MA8003.
Works a treat now. Got some LED replacement lamps for the blown vu lamps and added a 825ohm resistor to give them that warm glow of the original. Got them from a guy who actually makes these lamps from a well known auction site. They really work well.
Auto cut off at end of record now works due to very good advise on here regarding where the issue was. (seized lever on pivot) heated it gently to remove and clean and tiny bit of black grease that I had from Panasonic for greasing mechanics on their vcr decks.
Cassette playback issue could not be resolved with good cleaning with servisol 10. So dare I say but I removed it completely and bridged the circuit board for playback only. I will keep the slide switch as its part of the deck and can always put it back in to keep it original if I ever sell it? I will never use the deck to record in any case. This now works a treat.
Thanks to all you guys who helped me along with repairing my srx20
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