[Ron Ramirez]

As most of you know, Debbie and I moved into a 1960 Mid Century house just over a year ago.

One of the amenities of this home is an original Rittenhouse RCM-3 AM/FM radio and house intercom.

According to some paperwork I managed to acquire for this unit several months ago, the RCM-3 was the first all-transistor unit of this type.

The master unit still worked when we moved in, but its performance was less than optimal; controls were scratchy (some DeoxIT soon took care of that), and the sound was not optimal. In fact, when the set was first turned on, there was a lot of distortion in the sound which cleared up somewhat after the unit was left on awhile, but still seemed subpar to me.

So last week when it quit working entirely, I decided it was time to restore this unit in the hopes that it will last another 54 years.

In case you do not know what I am talking about:

[Image: http://www.philcoradio.com/images/phorum...e00001.jpg]

The next several posts will illustrate what I did to return this unit to working order.

[Ron Ramirez]

When the Rittenhouse stopped working last week, I decided that this would be the perfect time to do something I had wanted to do almost since we moved in this house - pull the unit from the wall and replace all of the 50+ year old electrolytic capacitors.

But the first order of business was to find out why the unit was no longer getting power.

I soon found the culprit.

[Image: http://www.philcoradio.com/images/phorum...e00002.jpg]

That's the original 24 volt transformer on the left. I know this is the original transformer because it has "Rittenhouse" stamped into the case. It's a good thing it also had the voltage and VA rating stamped into it!

The new transformer on the right, obviously from Ace Hardware, is rated at 24 volts, 15 VA. The original Rittenhouse was rated at 24 volts, 10 VA. So the Ace transformer will be an excellent replacement.

How did I know the original transformer was bad? Not only was 24 volts AC no longer getting to the master control box upstairs, but the transformer had a terrible burnt smell, so it had died the death.

[Image: http://www.philcoradio.com/images/phorum...e00003.jpg]

The transformer mounted on a junction box in the basement, on the metal cover of the box through which the wires ran. The replacement transformer, shown here already mounted to the metal cover, mounts in the same way.

One good feature the new transformer has, which the old one didn't: a ground wire.

[Image: http://www.philcoradio.com/images/phorum...e00004.jpg]

Here is the new transformer mounted onto the junction box in the basement. Previously, the wires leading to the master control unit were merely stripped and wrapped around the 24 volt screws. I added the spade terminals for a neater installation.

After installing the new transformer, I turned on the breaker and checked the box which holds the master control unit. Yes, now it was receiving power as it should!

[Ron Ramirez]

The RCM-3 master control unit was taken to my workbench and laid face down on an old towel, to protect the front panel.

[Image: http://www.philcoradio.com/images/phorum...e00005.jpg]

This would be a very tricky operation - because I have no schematic. That's right, the old "operate by the seat of your pants" technique. One wrong move on my part and I would have a static display.

Carefully, I began to disassemble the unit. Soon, it looked like this:

[Image: http://www.philcoradio.com/images/phorum...e00006.jpg]

My mission was to replace all electrolytic capacitors.

[Image: http://www.philcoradio.com/images/phorum...e00007.jpg]

Here is a close-up of the circuit board that contains the AM tuner (save for the actual tuning condenser which is on the FM tuner board), and the audio amplifier circuitry. This board has mostly GE transistors although I saw one Texas Instruments transistor - perhaps this one was a replacement?

I noticed something very interesting while looking over the FM tuner board:

[Image: http://www.philcoradio.com/images/phorum...e00008.jpg]

Yes, Philco transistors! I was not expecting to see these.

From here on, I had to work very carefully. I would replace one electrolytic at a time, making double sure that the replacement went in with the same polarity as the original.

[Ron Ramirez]

After a few hours of work, the AM/audio board had a complete set of new Nichicon electrolytics:

[Image: http://www.philcoradio.com/images/phorum...e00009.jpg]

The FM board had two axial electrolytics. These were also replaced:

[Image: http://www.philcoradio.com/images/phorum...e00010.jpg]

While I was in there, I lubricated the ball bearings of the tuning cap. I had noticed when tuning FM stations that it was very scratchy (but not on AM). I looked it over as best as I could for shorting plates; I saw none. So I hoped that lubrication would help.

[Ron Ramirez]

The tuner boards having all new electrolytics, I then turned to the power supply.

[Image: http://www.philcoradio.com/images/phorum...e00011.jpg]

There are two electrolytics here; both were replaced with new 2200 uF caps. I noticed that one of the four rectifier diodes had been replaced at some time. So, as a preventative measure, I replaced all four. The .05 uF ceramic disc caps in parallel with each diode were also replaced.

Once these parts were replaced, I put the unit back together...

[Ron Ramirez]

...I said a silent prayer, crossed my fingers, and reinstalled the RCM-3 in the wall upstairs.

I went back to the basement to turn the breaker back on, then returned upstairs to see what happened.

Thank God, I was rewarded with smooth-sounding music as soon as I turned the unit on and tuned in my SSTRAN signal...

[Image: http://www.philcoradio.com/images/phorum...e00012.jpg]

My next move will be to attempt to align at least the AM side; it seems to need it more than the FM side does. Both bands now sound nice and clear; that distortion is gone, and tuning FM no longer includes a scratchy sound as the tuning knob is turned.

Whew!

I am so glad this turned out so well...

...and it should be good to go now for several more years.

[klondike98]

Good work Ron!! 

[sam]

HEY RON
what`s the receivers look like? can you play music in all rooms
noticed it has a jack next to volume. small for phono input

[Ron Ramirez]

Bob - Thanks!

HEY RON
what`s the receivers look like? can you play music in all rooms
noticed it has a jack next to volume. small for phono input

Do you mean the remotes? I'll take a picture of one, and post it, tomorrow. Yes, we can play music throughout the house, which is why I really wanted to get the RCM-3 master control unit going again. The RCM-3 is in the dining room. There is one remote in the living room, and another in the basement. The jack next to the intercom volume control is indeed an RCA jack for an extra phono input. It also has two jacks in the basement wired up to the master control unit; these are for phono or auxiliary input. The jacks in the basement look like the old-time TV antenna sockets I used to see in electronic catalogs when I was young, but they are labeled "Rittenhouse".

[NostalgiaRadioTime]

Very cool to have that unit working again. A great feature to have in a mid century modern home. Your careful, thorough work paid off!

[Eliot Ness]

Pretty cool

[w4rtc]

Joe

[morzh]

IRC still makes resistors, I use them....nice to see some longevity in this all-chinese business today.

Did Philco make their own transistors or did they relabel?
To me it would be too much for them to make their own, semiconductor foundry even at those times was a big investment and unless you cater to other folks, would be a money loser.

[Ron Ramirez]

Semiconductors are one of the big reasons Philco nearly went under in 1961 and were rescued from oblivion (temporarily, as it turned out) by a buyout from Ford.

Philco invented the surface barrier transistor, and pushed them heavily.

At the same time, Philco had diversified into a huge conglomerate, building consumer electronics, white goods (refrigerators, freezers, ovens, washers, dryers), and they also had a Government and Industrial Division which ended up being a huge monetary drain on the Corporation. Philco also dabbled in computers towards the end.

As John Wolkonowicz said so well in his Philco thesis, "Philco's dream was to become another RCA."

But I digress.

[KCMike]

Good job Ron. Interesting history lesson also. By the way, did you have to change the Philco transistors?