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Photofacts For Sale

Ultralight Modification

Smile, You're on Candid Camera!

Looking for scan of Radiola 20

Looking for info on clock radio manufactured in New Jersey

Overheating Output Tubes

Photofacts For Sale
Submitted by Bob Pilcher 10/20/2010

I have several thousand of Sam's photofacts that I need to dispense of.  If the club members would like some I will make them a very good offer (i.e 10c per folder.)
Also have many up till 1980 unopened from RCA in Camden.

Bob Pilcher

Ultralight Modification
Submitted by Nick Senker 1/17/2009  Updated 01/22/09

Having been impressed by Walt Heskes' and Al Klase's modifications of the Sony SRF59 ultralite AM/FM pocket receiver, I decided to try a modification of my own.  Both Walt and Al used a vernier tuning dial with impressive results as the limitation of the Sony SRF59 is in its coarse tuning dial arrangement.  As I don't have such a vernier dial, I decided to check out some other options with the miscelaneous hardware and junk components I did have. 

I found an old Panasonic AM/FM 'Walkman' type with a conventional dial cord and pulley arrangement with allows for a  mechanical reduction in the turning ratio between the tuning knob and the tuning capacitor.  This probably is not as good as a vernier dial but should provide a significant advantage over the Sony 'direct' tuning setup.  This setup should not cause any permanent damage or changes in the Sony circuit board and hopefully will be reversible if I do come across a vernier dial or choose another method.

As can be seen in the photo, the Sony is disassembled simply by removing the two small screws in the back and carefully prying the front and back sections of the plastic case apart with a dull knife blade.  The Sony circuit board can be mounted on a small perf board (available from '') using the two original mounting holes and the Panasonic pulley assembly snapped into place adjacent to the Sony chassis.  The Sony dial wheel is unscrewed from the tuning cap and the dial pulley from the Panasonic is mounted in its place.  The larger Sony dial wheel is used in place of the small Panasonic tuning wheel to further enhance the tuning ratio advantage.

I am not finished with this modification yet and will supply another photo and update when I get everything mounted but I wanted to get this idea out there in the event others might want to try this approach or improve upon it.

Update: 01/22/09

Well the modification looked simple and straightforward!  That's never the case.  The transfer and mounting of the Panasonic pulleys and dial cord to the perf board went smoothly as the perf board is about the same thickness as the Panasonic circuit board.  When I put the Sony chassis next to it however, the tuning cap extended about 1 cm above it so the pulley height didn't match.  Two choices; raise the pulley assembly or lower the Sony chassis board.

As I had drilled holes in the perf board and glued the pulley assembly in place, I didn't like the idea of raising the pulley platform.  I then tried to lower the Sony chassis by cutting holes in the perf board and mounting the Sony chassis from below in the holes.  This became very messy however and looked sloppy.  Besides, the perf board was clad on the underside and I was worried about possible shorts or at least interference in the RF circuits.

My final solution can be seen in the attached photo:  I cut the perf board at the pulley assembly and mounted it on a 1/2" block over a small piece of hardboard,  I then positioned the Sony chassis next to it and fastened it with the original Sony mounting scews and a brass screw and washer at the top.  The heights of the pulleys now match and with the right spring tension the tuning is very smooth,

I had tried to incorporate the original Sony plastic case to accomodate the battery but this hampered access to the switches.  I therefore mounted a separate battery holder.

The result is a significant improvement in the tuning ability of at least two times over the original design and it is comparable to any standard tube type radio with a dial cord and pulley arrangement.  Your comments would be appreciated. 

(By the way, the total assembly weighs in about 4 oz and meets our DX context requirement for Ultralight receivers)

Nick Senker

Smile, You're on Candid Camera!

Club VP Harry Klancer was looking up directions to Ray Chase's house on Google before heading over there. Harry clicked on the "Street View" button on Google Maps, and when the picture came up, Harry's wife commented that a fellow in the picture looked a lot like Ray. On closer examination, the dog looked a lot like Ray's dog too! Look out, Ray. It seems as if the "pooper scooper" police are watching you!

Looking for a high quality scan of a Radiola 20 from Dec. 4 1926 issue of Liberty Magazine
by Robert Lozier 11/8/2008

Looking for a high quality scan of a Radiola 20 ad, in color, that
appeared in the Dec. 4th, 1926 issue of Liberty magazine.
It could have also been in other publications.

It is inside a western theme ranch house with the family around a small
Christmas tree and Junior on his rocking horse with the Radiola 20 &
speaker in the background.
Any other high resolution Christmas theme scans from the 1920's IN COLOR
would be appreciated.
For a limited time I have started a page of Christmas related scans that
you can download.  
Warning, they are 300 dpi scans so are 1 to 4 meg. each.

Thanks, Robert Lozier  -

Looking for information on clock radio manufactured in New Jersey
by Robert Lozier 4/3/2008

I purchased a unique circa 1932 midget radio made in Newark, NJ by Radio Products Co. at the CCAWA conference a week ago.  It has tubes in it not used in any other radio and a electric clock is mounted coaxial with the loudspeaker.  I know of only one other person, Alan Douglas, that has one.  He wrote a great article on the set in the April 1990 RADIO AGE. Unfortunately mine is missing the clock.  Is there anyone that knows for certain the manufacturer of the clock used in this radio…  This really unique radio deserves to be made whole again…

Are there any other known examples of this set?

Thanks, Robert Lozier  -

Overheating output tubes
Submitted by Nick Senker 6/4/2007

I would like to share with other members my experience with overheating output tubes.  This concerns two 6F6 p/p tubes in an RCA amplifier chassis for a RCA 612V3 radio/phono circa 1950 (Riders 17-34).  The
tubes had been replaced with new old stock versions.  One was a shoulder type, the other a GT type (small envelope).  Only the GT tube overheated, regardless of which socket it was in.  I was advised that
the GT type was electrically equivalent and shouldn't be causing the problem.  I was concerned there might be a mismatch but I didn't have  substitute tubes to settle this question.

The grid bias was listed as -25V and I measured about -22V so I didn't think this was a problem.  I replaced the paper coupling capacitors anyway since a reduced or positive grid bias could cause overheating.  I also replaced the .0035 mfd caps from the plates to ground ( I don't know the purpose of these?) The screen voltage measured the listed 270V  but the plate voltage was low, about 320 instead of the listed 375V.   I didn't think this was too bad given the age of the set.  The resistances of the field coil and the output transformer were about right. 

After much fruitless checking I discovered a bad connection feeding the 375V to the output transformer center tap.  The high resistance connection was preventing the proper voltage to the plate and the low potential between the screen and plate was causing the screen to draw excessive current (I think) causing the overheating.  At least this is my explanation.  Anyway, resoldering the plate feed connection solved the problem.  Would appreciate any comments or other explanations. 

Nick Senker

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