[Boatanchors] RME 69 Crystal Filter and Cc/C adjust

[Al Klase]

Hi Bill,

I have my 69 on the bench, and it appears my restoration and alignment 
efforts of the late '90 have held up.

The positions of the Crystal Filter Switch (B) (upper right corner) are, 
left to right, OUT - SERIES - PARALLEL

The Crystal Selectivity (E) variable capacitor, CH, is just below the 
switch.

I'm blessed with an original copy of the documentation, and the switch 
connections are clear, unlike all the third-order scans on the web..

It's a single-pole three position switch, with the common terminal 
connected to the grid of the 6D6.
In the left-hand position, it shorts out the crystal for full frequency 
response.
In the middle position it does nothing.  This allows "normanl" crystal 
filter action.
In the right-hand position it shorts out the "phasing capacitor" CI, the 
trimmer inside the filter can.

Sandy's right, your going to need a crib sheet for the unmarked front panel.

I strongly suggest you replace ALL the paper caps before you attempt 
alignment.  DON'T EVEN TRY TO TUNE JUNK!

I'll try to get this stuff posted to my website soon. 
http://www.skywaves.ar88.net/commrx/RME/RME.html

Good luck,
Al

On 4/14/2013 10:58 AM, Bill Carns wrote:
> I am doing my first alignment of a RME 69 receiver.
>
> I am having trouble reading the schematic in the area of the crystal filter
> but there is apparently some confusing info.
>
> There is not much in the manual about the switch positions for the filter
> selector switch. In the alignment section it refers to the middle position
> of the switch as the "Series" mode position.....fine.
>
> That implies that there is a "Parallel" mode position...  ???  Maybe.
>
> There appear to be three positions of the switch..   10:00, 12:00 (Series)
> and 2:00.   But, in the schematic there appear to be only two positions and
> it is not clear what the wiring is in each position, or which position it is
> shown in..
>
> I want to understand this guy before I leap in.
>
> Also, anyone out there have any words of wisdom for setting the C and C(c)
> capacitors that appear to be a "factory Setting on Band one, but "Should be
> kept to an absolute minimum, so as not to degrade the upper bands.
>
>
> 75 years later, I am not sure I trust the "factory" settings for C and Cc,
> which could have shifted or been messed with along the way.
>
>    Any   ....  HELP !  is appreciated.
>
> Bill
> N7OTQ
>
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-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/