Removal of ZF band filter housing for Loewe Opta 3751 W UKW

ID: 386859
? Removal of ZF band filter housing for Loewe Opta 3751 W UKW 
26.Oct.15 09:29
39

Thomas Moersheim (RP)
Articles: 2
Count of Thanks: 3

I'm starting with my tube radio hobby. I recently bought the 3751W. I started the cleaning process and initial testing. The transformer works fine and the NF part works, although I have significant loss of volume as soon as I activitate the sound poti. Only if it is off, I get sufficient sound using the amplifier to e.g. drive my Iphone MP3 player. I will deal with that later, just order a complete set of spairs (tubes, R,C). All Frequncy bands are silent, just static noise so signal. As a next step I was about to check the band filters, by removing the metal housing. After removing the top pin the housing still resisted to be lifted up. As I did not want to damage anything I did not increase force to pull up. Any tip avaialble how to remove the filter housing safely would be greatly appreciated. regards Thomas

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 2
removal of ZF housing 
26.Oct.15 23:58
39 from 2792

Tony Bartunek (CDN)
Articles: 16
Count of Thanks: 3

Hello Thomas,

Do not touch the ZF cans, ever !  Carefullly place the cover back. Get yourself a schematic diagram and start measuring voltages in RF and  ZF(IF) stages. Usually B+ will be missing somewhere on the plates or screen grids. (G2), if you have audio stages working. 

Also check for proper tube locations in each sockett and check or replace those tubes in stages.

Hope that helps, Tony at www radiodoctor.org  in Ontario, Canada

I

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