[David B]

I am undertaking the restoration of a Philco 620 radio, replacing the capacitors, renewing one weak tube, re coning the speaker, and refinishing the cabinet. What makes for a good restoration and what specific things do some of you who have been in this business for a while consider to be a good restoration so as to make the radio work like new?
Please be specific. Thank you

[AI2V]

You can get probably enough descriptions of what a "restoration" is as is the number of member of this group.

Electronically you are on the right course; whenever practical, try to keep any of your repairs inconspicuous. Learn to refill the capactor tar blocks. Never use plastic or modern wires- they stand out terribly. Salvage wires from junkers whenever you can.

The cabinet "restoration" opinions will vary wildly. Some will insist that only the original toned lacquers be used; some use stains and urethanes; some like the distressed, aged look. If I say what I use, I would expect to be blitzed by the those who choose the other methods. I kind of doubt that anyone would want a "restoration" that shows heavily damaged finishes or one that has simply been sprayed with glossy urethane. Removing photo-finishes in the 1937+ models make most of us in this group want to puke. Sanding should never be done- when a pre-1937 finish is that bad, I remove the finish with acetone (only)- someone will probably blast me for that!

In the end you want a radio that works well and looks nice. Don't cut corners, pay attention to detail, and don't hesitate to ask questions of the group.

[David B]

Thank you, great advice. Other than replacing capacitors what else would you do besides replacing damaged wiring and bad tubes. What makes for a good electronic restoration?

[Raleigh]

Many times resistors are very out of tolerance, usually high. I measure all the resistors with one lead de-soldered so other components are clearly out of the circuit. If they are more than 10% or so out of tolerance I replace them.

I think other people use 20% as the limit for resistors. I'm not sure how much it matters whether you use 10% or 20% as the limit, because I have taken resistors that were 200% or 300% high out of old radios that seemed to be working fine. I hope others will weigh in with opinions on this as I am really not sure what is the best approach. Possibly a resistor that has gone out of tolerance will continue getting worse.

Some resistors are exactly the right value after 50 years, but others have changed a lot. In the radio I am recapping now, a 42-350, almost every resistor is 20% or more high, so I am replacing almost all of them. This one will definitely not look original inside when I am finished.

A question on recapping for the more experienced restorers: how many of you re-stuff the wax/paper capacitors? Do any of you consider it essential for authenticity?

I always re-stuff the bakelite caps. They are a snap. It isn't a snap to re-stuff all the metal 'lytics on the top side of the chassis, but I do it whenever possible. Sometimes 3 or 4 modern lytics won't fit in the can. On my current project I re-stuffed both of the cardboard-bodied 'lytics even though they don't show. I haven't yet started to re-stuff the wax/paper capacitors. I put all of them in a big box, though, just in case I develop a passion for absolute authenticity someday.

[Raleigh]

Another thing: clean all the switches with contact cleaner and work them back and forth while the cleaner is still wet. I do the same with tube sockets.

I don't clean the potentiometers. I've had mixed results. Sometimes it washes all the lubricant out of the pot. Then it doesn't work right and feels rough, so I don't do it on the antique pots.

If pots are noisy I just run them back and forth quite a few times to wear the oxide off the metal wipers. That will quiet them for a while, but it is only temporary, I've found.

I also clean the outside of the chassis with 0000 steel wool and sometimes a damp rag. I don't go overboard with polishing. Philco chasses weren't intended to be works of art like some of the fancier radios.

Keep the steel wool away from the tuning capacitors, though, and wipe or blow the steel wool dust away carefully.

[gary rabbitt]

Hi John,
I am one that will restuff whenver possible

Of course the bakelites ar a must. Trying to replace those with a terminal strip and rewiring seems like it takes more time to do it that way.

I have got where I don't even have to unsolder the other terminals on te block. A little massaging of the block, turning it around, a little gentle heat from a small blow dryer, the tar plug and caps come right out.

The cardboard paper foil caps are not bad either. I have one several sets to try to keep the original look. I did a Fairbanks Morse last year, It had the original caps with the FB name on them. Slipping the cardboard tube off the cap is not bad. A little heat, pull on one of the wires and it slides right out.

I install a new cap with a touch of hot melt to hold it in place inside. The fill with a wax.
Even though supposedly no one looks under that chassis ( some do) I know that they are there, and that's all that matters.
What I will do it make a small pencil note under the chassis saying the caps were restuffed on XXX date, so the next owner doesn't just cut the old (restuffed new) out and replace. Keeping the diagram and repair notes with the set also helps.

As for the resistors, I have found some to be higher than original. If they are way out of line I will replace.
I just redone a Model 20 (got it fired up tonight) it had two resistors that were almost 40% higher. I left them in place though to see how the set functions. These are the old style of dogbones where Philco used only one or two colors, and had the old lead ends on them.
Keep the old parts with the set, in case someone wants to restuff. Once you throw them away, then it would be hard to find the authentic ones to restuff.
Take care and good luck with your set.
Gary.

[AI2V]

Everyone seems to be on the same track!

As for the BED (color code= body-end-dot) or "dogbone" resistors- start with the higher values first - above 5K- these are the ones that will be the most out of tolerance and will cause popping and sudden changes in volume. The lower value BED resistors generally retain proper resistance and don't cause many problems. More simply, any resistor with an orange, yellow, or green dot MUST be changed; the reds come next if necessary.

Audio tube sockets are a major cause of intermittents- I suggest that you take out the audio tube (tubes) and squeeze the socket contacts slightly with needle-nosed pliers. Wiggle the tube around a bit when reinserting it. Audio tubes run quite hot and allow metal fatigue and contact oxides to develop in the sockets.

I strongly suggest a contact cleaner that contains "cramolin". I have been using the same 2 oz. bottle of pure industrial Cramolin for about 40 years but I dilute it about 100:1 with wood alcohol, and apply with a fine needle syringe. Ten diluted drops will service an entire radio, including pots. Cramolin cleaners are on Ebay- use it VERY sparingly, applying with a toothpick only.

A lousy volume control pot is most often from the carbon resistor layer being worn through; these can't be fixed. RadioDaze has lots of replacement pots with switches that the buyer configures. Don't torture yourself with a ratty worn-out pot- replace it.

Before long you will have a great 620!

[gary rabbitt]

Hi Ai2,
The dogbones are dfferent than the three color bod end dot marking. These are either one solid color, I think the orange was 50,000 Ohms, there were others that had only one color and you have to use the legend on the diagram to tell what was what.

I have found lower BED resistors to be out of whack also in addition to the higher values. Some do hold their values,(for some reason) so I leave them alone. It does make sense to check all of them.

The volume control issue, many can be cleaned, but often the carbon may be worn thru. Less sommon are the wirewound elements being worn, but I guess it happens.

On volume controls where a substitute is hard to fins, some have used 'resistance' paint, such as that used to repair the rear window defogger. They have had mixed results, so it may be worth a try to save an original control, until one is found.

Take care,
Gary.

[David B]

Guys:

Thanks for the great ideas, I apprecaite it.

God Bless,

Dave B.

[Guest]

Concerining "restuffing" of the "bakelite" caps...

The bakelite block caps are almost always at least one
of them used as a line bypass cap. This cap must be
either X or Y rated (Y if it connects to the chassis,
even indirectly, or in hot chassis sets, or if connecting
the floating ground to chassis, X otherwise). Even if
it won't fit, then put it outside the block. DON'T use
a "regular" cap in this location.

[Texasrocker]

I dont mean to offend any vintage radio-restorers here at all!! I personally dont see any reason at all to restuff orig paper caps, orig bakelight, and/or metal-housing filter caps, unless "space" under chassis doesnt permit for room to add a terminal-strip! Always remember, that the next owners of all these great vintage pieces of "Radio Americana",(your restoring now),.. will someday fall into the hands of future restorers after all us restorers are gone!! Do you really want the next-generation of vintage radio techs to have to go thru the process of buying a copy of "Philco Condensers & More" to find out just what you "re-stuffed" those old bakelight condensers with?... (after digging thru your re-stuffing) process to again replacing all your "ideas" of totally Original concept?
Sorry, but I personally think the next generations of techs that restores all our "previously restored" vintage Radios (all brands), would expect us to to take the "mystery" out of the project, use "well marked components caps,etc, Before!!, they have to recap the radios 40-50 yrs down the road!? I always realize, that all my vintage radio collection will "outlive" me by many years!! And all the next owners want, is for them to "work",, and be "easily" repaired if need be. Seems to me that leaving "well marked" capacitors (not hidden in orig bakelight housings), by taking time to install terminal-strips, would be a much better idea for the future restorers??? You reckon?? Now, throw your bricks at me,... Randal

[gary rabbitt]

Hi Randal, I'm not going to throw anything at you

"Seems to me that leaving "well marked" capacitors (not hidden in orig bakelight housings), by taking time to install terminal-strips, would be a much better idea for the future restorers??? You reckon??"

Nope. Adding the terminal strips creates more work than just rebuilding the block. Often the block are used as tie points and those will have to be changed also. You could also run into "lead dressing" issues of the parts placement. Maybe picking up a hum or stray signals when the parts are located in different places. Even a half inch could make a difference.

There is usually no mystery in finding the values.
They new parts are not "hidden per se, unless you fill the block up with tar again. Removing the one hol down bolt, and turning the block over will let you actually look at the values of the caps we installed. installed. WE actually have made it easier than they were originally built. The original insides were not marked with values. Mr. Future owner will thank us for not repotting with tar.

If the future user is truly interested in restoring a set again, then I would say he/she should get a reference book on the blocks.
For those who can read a diagram, you really don't need a resource guide, and could fgure out what s in the block. The guide will save a little time though.

For those down the road, I think they will want something original looking to see how it was "back in the day". Otherwise why not gut the cabinet out, and install a cheap Chinese piece of junk? Then when it fails, throw in the landfill, and install another cheapo board. Heck, throw away the old wood cabinet and use a plastic one. That will make it easier on the future guy, because he will not have to worry about refinishing. Or just throw the whole set away, and get an I-pod thingy, it's easier and smaller. All those "complicated" tubes and wires may give someone an uncomfortable feeling.

There is more to having a radio then just to hear sound come out. Looking at parts that either are original or look original is part of the charm.
I'd much rather see a chassis with the blocks like they were when new, than to see a chassis with those gaudy looking yellow caps glaring at me. Unless of course, it is already missing the blocks that someone thoughtfully removed. Then, I'd have to restuff some Philco wax caps and install those.

Let me say Randal, that if one finds a Philco chassis that has all the parts removed, then it may be ok to install terminal strips and such to save the chassis.

Just my opinion though, have a great evening.
Gary.

[Ron Ramirez]

All those "complicated" tubes and wires may give someone an uncomfortable feeling.

LOL!!! That sounds just like Michael Savage talking!

But anyway...

Randal, no bricks here either...but Gary has already said it best for me. I also believe in restuffing bakelite blocks. It isn't that difficult once you get used to doing it. Plus, most of us do not refill the block once restuffed. There is no need to do so. No one will see inside the block unless it becomes necessary in the future to RE-restuff; then, as Gary said, we have made it easier for the next person to replace the caps.

Remember, Randal, you promised your next batch of bakelite blocks to me anyway!!! HA! HA!