grundig: RF250U/Stereo (RF 250 U /Stereo); Konzert

ID: 167964
grundig: RF250U/Stereo (RF 250 U /Stereo); Konzert 
25.Jul.08 11:18
0

Wes Hancher (USA)
Articles: 2
Count of Thanks: 6

Hi ... Can anyone provide alignment instructions for this radio?  I have all the original paper work, including schematic, owners manual, etc., and nothing provides info on alignment. 

The only thing the schematic says that I think might be related is: "Voltages measured to against chassis with Grundig VTVM.  Measuring values valid for MW FM PU without signal on aerial." 

So it sounds like you don't need a signal generator -- only a way of measuring the voltage on the pins of the tubes.  The schematic does show what these voltages are to be.  But what coils are to be adjusted?

Is it possible that this radio is so recent (1968, I think) that it simple does not require alignment?

Any information would be appreciated.

Thanks,

Wes

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 2
How to find Alignment 
25.Jul.08 12:25

Heribert Jung (D)
Moderator
Articles: 999
Count of Thanks: 13

Hi Wes,
 you find an answer to your question on the schematic bottom right: There is written Chassis CS200U. When you look for CS200 in RM you get many hits. The first hit shows KS720 with Chassis CS200. There you find the Alignment pages: d_grundig_1966_ks720_abgl.pdf

As there is a different between CS200 and CS200U the alignment must not be loaded to RF250U, but it can help you!  An Alignment for CS200U is welcome, so we can see if there is any difference.

Heribert

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 3
Voltages 
31.Jul.08 04:00

Todd Stackhouse (USA)
Articles: 151
Count of Thanks: 2

...the schematic gives operating voltages you should expect to see at the tube pins with no signal present.  Those will have little or nothing to do with alignment; they're given to help with troubleshooting.  RF/IF alignment was not something the average owner would be expected to have the equipment or knowledge to attempt; therefore alignment instructions would not have been included in the papers that came with the set.  (Even the schematic that was included would most likely have been of little use to the average set owner who wasn't necessarily technically inclined...but was certainly nice to have if the set ever needed repair, especially here in the US where any kind of service literature would very likely have been otherwise hard to come by...)

...To respectfully reply to Herr Jung's warning: The 'CS200' and 'CS200U' designations most likely refer to the German domestic and US-export versions, respectively, of the same chassis.  I believe the RF/IF alignment procedure is likely to be the same for both versions except for the alignment of the FM dial.  You will probably be able to use the CS200 alignment procedure without any problems (once you've translated it!), except you will have to change one of the FM dial alignment frequencies.  The procedure calls for three adjustments to be made with the FM dial set at 88 MHz and then two adjustments at 102 MHz; that is based on the typical German FM dial at the time whose range was 88...104 MHz.  For the US version, based on the US 88...108 MHz FM range, you would simply change that upper-end frequency from 102 MHz to 106 MHz. 

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