My FM converter for tube radios using the dial and tube amplifier

[david winter]

The switch is a miniature type, so you must carefully press it.
I will add this to the description.
If you broke it, the module isn't dead for such: the switch grounds a pin of the PIC when pressed, so you can always add a tiny wire on one of the left solders of the switch (i.e near the edge).
To simulate a press, ground your wire for less than one second.
What's the total capacity of the tuning capacitor with all sections combined together ?

[bobhowe]

Originally Posted by FStephenMasek

It works on the Capehart Panamuse. It sounds great, with the two original speakers and the tweeter and inductor & capacitor crossover I added.

I connected all three of the original pre-war FM tuning gang sections together (orange wire).

I connected the module antenna terminal to one of the original FM doublet terminals on the back of the chassis.

The tiny switch is difficult to use. I destroyed one module trying to press the switch. A larger switch with a light to indicate when it has been pressed would be a great improvement.

I mounted it with silicone caulk.

Hi Stephen I used a blunt wooden cocktail stick to press the tiny switch hope this helps you when you use the the other modules you purchased

[bobhowe]

Originally Posted by FStephenMasek

It works on the Capehart Panamuse. It sounds great, with the two original speakers and the tweeter and inductor & capacitor crossover I added.

I connected all three of the original pre-war FM tuning gang sections together (orange wire).

I connected the module antenna terminal to one of the original FM doublet terminals on the back of the chassis.

The tiny switch is difficult to use. I destroyed one module trying to press the switch. A larger switch with a light to indicate when it has been pressed would be a great improvement.

I mounted it with silicone caulk.

Hi Stephen I used a blunt wooden cocktail stick to press the tiny switch hope this helps you when you use the the other modules you purchased

[david winter]

I thought about using another larger type of pushbutton, but the cost was quite higher in some cases, and the pin to be pressed was still too small, hence a worry that someone's tool used to press it glisses and hits a part. So I used that tiny flat pushbutton without pin.

But I'm open to the use of another type for the next production. Feel free to propose any model.

[FStephenMasek]

Mouser has this sub-miniature push button switch for just $0.61 each:

https://www.mouser.com/ProductDetail...kbBY57jQ%3D%3D

[FStephenMasek]

By the way, I hope I'm the only one to have problems with the switch.

What is a "cocktail stick" - the thing known as a toothpick in the USA? I have cotton swabs with wood shafts which might work if cut and sanded smooth (or rounded a bit).

[bobhowe]

Hi Stephen here is a picture of a cocktail stick and it's known as a toothpick as well in the UK

[John M0GLN]

Originally Posted by bobhowe

Hi Stephen here is a picture of a cocktail stick and it's known as a toothpick as well in the UK

It's intended purpose is for putting a Cherry on to flavour a Gin & Tonic or something similar.

John

[bobhowe]

Originally Posted by John M0GLN

It's intended purpose is for putting a Cherry on to flavour a Gin & Tonic or something similar.

John

Or nibbles such as Hot Dogs Cheese or Pineapple with a drink

[Station X]

Let's get back on topic please.

[david winter]

I thought about the following switch model: PTS526-SM15-SMTR2-LFS

What do you think ?


Also, one tiny update:
Buyers located in the USA and Canada will now receive a module programmed for 75µs deemphasis.
Other buyers will receive a module programmed for 50µs deemphasis.
As the firmware hasn't changed except this parameter, the installation, calibration and use the FM-DW module remain the same.

[murphyv310]

Hi
At last I've time on Friday to fit the updated module to the Pye radio that is the recipient.
The set has paralleled heaters and is obviously an AC set only. It'll basically just have the module and an audio amplifier.
Hopefully will report back at sometime over the weekend or early next week.

[david winter]

Hi

Check the winding of the heaters circuit. If it has one grounded center tap, you'll need a voltage doubler as you will have only half of the heating voltage between either end and the chassis. This, for 4V (or more) heaters. Heaters under 4V need a voltage doubler in any case (or a separate DC power supply for the module).

Just converted a french 1933 radio with 2.5V heaters (and center taped heater winding). I used a tiny chinese 9V power supply. Works nicely after replacing the defect 80 rectifier and almost dead 47 output tube, and changing the AM reflex circuits to a normal preamplifier around a 57 penthode.....

[FStephenMasek]

Originally Posted by david winter

I thought about the following switch model: PTS526-SM15-SMTR2-LFS

What do you think ?

That looks like a significant improvement!

[FStephenMasek]

Originally Posted by david winter

Hi Just converted a french 1933 radio with 2.5V heaters .....

I found some nice small 120VAC to 6.3 VAC transformers, but it would be difficult to add the FM module to radios with the volume control in the antenna circuit. Yes, it could be heavily modified, but there are still thousands of AM (MW) stations in the USA, so disabling AM is not a good idea.

[FStephenMasek]

Someone asked for pictures of radios to which this module has been added. This is my 1941 Capehart Panamuse playing on 94.7

[david winter]

Originally Posted by FStephenMasek

I found some nice small 120VAC to 6.3 VAC transformers, but it would be difficult to add the FM module to radios with the volume control in the antenna circuit. Yes, it could be heavily modified, but there are still thousands of AM (MW) stations in the USA, so disabling AM is not a good idea.

Either you are a collector with enough radios to keep a specific set as it is, or you just have one radio to convert and in almost every case you will make the necessary mods for the FM conversion. On the 250+ radios I converted for my clients, NONE complained about the AM loss. On the 50+ FM-DW modules I sold so far, same thing. No complaints. So it's clearly not that much of a problem, but rather your personal opinion. By the way, how many AM (MW) stations can you receive on a single MW band over the thousands ?

[jhalphen]

Hi to all,
Hi David Winter,

Re: FM only or keeping AM alive (MW in UK & Europe):

FStephenMasek is in California. In America (& Canada), the AM band is still very much alive. In major cities, stations all over the dial.
The European situation is totally different. AM is already dead or dying, hence most of your customers don't care if their radio is converted to FM only.

For our worldwide friends, the current status of AM in France:
One station, RTL Luxemburg, MegaWatt power on LongWave.
That's it !

Best Regards
jhalphen
Paris/France

[bobhowe]

Originally Posted by FStephenMasek

Someone asked for pictures of radios to which this module has been added. This is my 1941 Capehart Panamuse playing on 94.7

Hi it was me asking for pictures would it be possible to post some pictures of the module fitted inside thanks

[FERNSEH]

Bush DAC90A: Attachment shows a suggested location for the FM module.

DFWB.