Welcome to Australia's only Vintage Radio and Television discussion forums. You are not logged in. Please log in below, apply for an account or retrieve your password.
Australian Vintage Radio Forums
  Home  ·  About Us  ·  Discussion Forums  ·  Glossary  ·  Outside Links  ·  Policies  ·  Services Directory  ·  Safety Warnings  ·  Tutorials

Special Projects

Forum home - Go back to Special Projects

 Philips 100 radio resurrection - Part 1.
« Back · 1 · Next »
 Return to top of page · Post #: 1 · Written at 7:37:33 AM on 5 September 2020.
Fred Lever's Gravatar
 Location: Toongabbie, NSW
 Member since 19 November 2015
 Member #: 1828
 Postcount: 915

JimB was good enough to let me loose on the Philips 100 radio as discussed in length elsewhere.
In the first part I half stripped the chassis and got some music out of the front end of the set.
I needed to do that to test the tuning and IF coils and the health of the mixer and IF valve.
That was satisfactory so the next part will be rewinding the sad looking power transformer!


Fred.

Philips Model 100 Restoration - Part 1


 
 Return to top of page · Post #: 2 · Written at 10:42:15 AM on 5 September 2020.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6531

Document uploaded.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 3 · Written at 1:06:19 AM on 7 September 2020.
Robbbert's avatar
 Location: Sydney, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 1464

I assume that ECB35 should be EBF35.

I'm surprised about that aerial wire. My 100A has a spring-loaded chassis-mounted metal terminal that looks original, rather than a random wire.


 
 Return to top of page · Post #: 4 · Written at 7:05:00 AM on 7 September 2020.
Fred Lever's Gravatar
 Location: Toongabbie, NSW
 Member since 19 November 2015
 Member #: 1828
 Postcount: 915

Hi Rob, they designed it so the set could be connected to the mains as a long wire antenna!
In a remote area that could be the difference between getting not much signal and getting something.
Ingenious and deadly.

This set does have the spring loaded terminal and that connects direct to the coil primary, point T1.
The two flying wires allow you to hook up the antenna configuration as shown on the sticker on the back of the chassis.
As the radio originally had a 2 wire mains lead, there was no earth connected to the chassis.
I will rebuild with a 3 wire mains lead, delete the two wires hanging out the back and the external aerial can connect to the spring loaded terminal.

The sticker will go.

Yep this chassis has the EBF35 with the odd heater pin connection and a ECH33 mixer.

Fred.


 
 Return to top of page · Post #: 5 · Written at 11:28:09 AM on 7 September 2020.
Robbbert's avatar
 Location: Sydney, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 1464

Yes those radios will need the longest antenna you can arrange, as they don't have much in the way of audio output, even at full volume - unless you live close to a transmitter.


 
 Return to top of page · Post #: 6 · Written at 12:10:40 PM on 7 September 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1981

A candidate for a reflex mod??


 
 Return to top of page · Post #: 7 · Written at 6:38:13 PM on 7 September 2020.
Fred Lever's Gravatar
 Location: Toongabbie, NSW
 Member since 19 November 2015
 Member #: 1828
 Postcount: 915

Hi Ian, might have a look at that.
My gut feeling is, as the HT is quite low the 6V6 is running very "soft" and will be part of the problem.
My set has the smaller PT and I now know why they went to a bigger stack, the small one is a stinker.
I have rewound it to the original specs and it has a large temperature rise with big voltage droop.
The 6V6 plate voltage will be around 180 volt if I am lucky.
I'll have to wait until get the whole thing running and see how it goes.
It really is a stripped design with 1 IFT only, uses a RFC on the mixer plate!
No AGC as well, could be fun.

Fred.


 
 Return to top of page · Post #: 8 · Written at 7:44:59 PM on 7 September 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1981

Well at least the RFC is tuned...

An idea instead of reflexing, given the 6v6 octal base. Replace it with a 6EM7. This is a dual triode that was used for 110 degree TV vertical deflection. Some early 60s AWA TVs used it.

The 2nd triode has a 10 watt plate dissipation but not unexpectedly has a low plate resistance of 750 ohms. So the speaker transformer primary will need to be changed to about 2k ohms. About 2 watts should be possible, depending on biassing and B+.

The gain of the two triodes (mu of 68 and 5.4 respectively) vs 9.8 for the 6V6 will give plenty of volume with enough gain to allow AGC to be added, at the expense of an extra cap and two resistors.

A far more civilised radio!

A search of the junk box might be needed, the 6EM7 has become a desirable audiophool valve and, when I just checked, is going for around $40! Or $35, including postage, on Ebay.


 
 Return to top of page · Post #: 9 · Written at 7:00:50 AM on 8 September 2020.
Fred Lever's Gravatar
 Location: Toongabbie, NSW
 Member since 19 November 2015
 Member #: 1828
 Postcount: 915

Ian, that is a thought!
Got some 6EM7 somewhere, could never figure out a use for them.
Can rewind a OPT to suit, easy.
This could be the "Hotting up the stock Philips 100" story!
Fred.


 
« Back · 1 · Next »
 You need to be a member to post comments on this forum.

Sign In

Username:
Password:
 Keep me logged in.
Do not tick box on a computer with public access.