Rogers Tuner info needed

[pwdrive]

A Leak Trough-Line tuner of similar vintage(ish) uses a 40uf + 40uf res/filter capacitor in a CRC configuration, if the Rogers has a reactance valve then HT ripple needs to be low. The HT filter arrangement in the Rogers is a CRC type, probably a CRCRC judging by the number of cut off capacitor wires, it looks to me as though the second filter resistor is just to the top left of the fuse holder as viewed from underneath.

Another observation is that one of the audio outputs is via a preset volume control, the other output isn't, the latter might be the output for a future stereo decoder.

Lawrence.

[pwdrive]

found this

The IF valves are 7 pin jobies, probably 6BA6's

Lawrence.

[FIXITNOW]

found this

The IF valves are 7 pin jobies, probably 6BA6's

Lawrence.

on the set I have they are all 9 pin

[Mark Hennessy]

That diagram is interesting as it gives an insight into how Rogers designed their gear, but sadly it's not the same product...

It shows a half-wave rectifier, but there is a bridge in the pictures (looks original). And it looks like it has V6 acting as a dual cathode-follower to buffer the output from a decoder, whereas the pictured unit just takes the output directly from the discriminator (which has twice as many diodes). And the diagram shows a magic eye.

[pwdrive]

The pinout's on the mixer/IF valves in your Rogers suggest ECF80's, it might be worth reverse engineering to obtain the schematic if you can't get hold of one, you could start at either end and work back doing it in stages, the discriminator will be a bog standard or slight variation of a Foster Seeley as the two diodes are both facing the same direction, the only other design I know of with the same diode arrangement is a balanced slope detector, it's less likely to be the latter and almost certainly the former.

The IF amp and IF limiter will be bog standard stuff, the osc/mixer I'm not to sure about but it might be an ECF80 configuration, if it is then the osc will probably be the triode section, if the RF amp is an ECC84 then it's most likely to be a cascode jobie, a bit of reverse engineering should tell what's what.

Lawrence.

[pwdrive]

This circuit might do as a basis for the Rogers RF amp, it's a double triode cascode with grounded cathode input, it shows capacitor tuning but I think in the Rogers it's incremental (inductive) tuning, the airwound coil and the small white capacitor connected to the RF amp valve socket in the OP's picture are most likely to be part of the neutralizing network.

Lawrence.

[pwdrive]

The electrolytic part way down this listing looks very similar to the one shown in the Rogers SFM11 on radiomuseum:

http://www.ebay.co.uk/itm/PLESSEY-1959-ELECTROLYTIC-CAPACITOR-2-X-40uF-amp-20uF-Valve-tube-radio-guitar-amp-/151427000188?_trkparms=aid%3D444000%26algo%3DSOI.DEFAULT%26ao%3D1%26asc%3D20140221143856%26meid%3D32f3d5288ce34da7bfc9705302f8b022%26pid%3D100012%26prg%3D20140221143856%26rk%3D5%26rkt%3D10%26sd%3D151135095203&_trksid=p2047675.l2557&nma=true&si=P9llJOK%252BabsRg0okHBxZU1tF0zE%253D&orig_cvip=true&rt=nc

http://www.radiomuseum.org/r/rogers2_fm_...fm_ii.html

Lawrence.

[pwdrive]

Rogers SFM Mk11 valve line up confirmed in the attached PDF, it also mentions AFC:

http://www.rogershifi.com/brochure/CadetV-ENG.pdf

Lawrence.

[Mark Hennessy]

That was a good find, Lawrence

[FIXITNOW]

Rogers SFM Mk11 valve line up confirmed in the attached PDF, it also mentions AFC:

http://www.rogershifi.com/brochure/CadetV-ENG.pdf

Lawrence.

very helpful thanks