1936 philco 610 radio

[JGlenn]

A friend of mine brought this radio to my place the other day to see if I could get it going again. He said it belonged to his great grandfather and hes kept it a long time so I'd feel kinda bad if I couldnt fix it for him. He said he tried to plug it in 10 years ago and the dial light lit up but no tubes lit up and not sound. I noticed the rectifier tube it missing so hopefully he didnt do any damage trying to fire it up. I'm going to get the missing tube and replacements for any others that are bad as well as replace all the caps. What else do I need to look at? I've worked on tube amps before but not a radio and nothing this old. Hopefully I can get it going for him and his father is a cabinetmaker so hes going to clean up the console as the finish has seen better days but the wood itself is still in decent shape.

[toxcrusadr]

610, is that the little tabletop that's round on one end, or a tall tombstone type? For some reason Philco made two radios in the 30s with the same model number.

A complete cap replacement should get it going. Both the paper foil caps and the electrolytics. Before buying a rectifier tube and caps I would check continuity on the power xmfr windings. I am concerned about no tubes lighting up. If the B+ winding is blown due to firing it up with bad caps or other windings are burnt, no amount of recapping and retubing will get it working. You'd need a power transformer. If you need help finding a schematic, etc. let us know.

[JGlenn]

It's a tall tombstone type. I noticed the different styles with the same model number as well when searching for info. It appears that they used the same speaker and chassis. So the power xmfr still could of been damaged by plugging in it with no rectifier tube ? I'm not sure if he said tube lit up or not he just said the dial light came on but no sound came out of. I know better then to even try to run it in its current state so all i've done so far is pull the chassis and speaker out of the cabinet and repair a tear in the speaker cone.

[Tom Bavis]

The 4-page Philco service bulletin for this set is on my web page: http://www.audiophool.cjb.net/Philco.html

You'll need to get the DjVu browser plug-in or IRFANVIEW with it's DjVu plug-in to view or print it.

[JGlenn]

very cool, thank you

[Reece]

Tom has referred you to his service notes which are excellent help for repairing this radio. I just want to pass along a way to determine if your transformer is OK.

If the dial light lit up then there should be power to the tube heaters since they're on the same transformer winding. What you can do to test the transformer: be sure the power cord is safe, change it out if required. Rectifier tube should be removed, which it is in this case! Turn the power on and listen, watch, sniff, around the transformer. If all seems calm, measure across pins 3 & 5 (the plates) of the 5Y4 socket: these should be yellow wires coming from the transformer. You should get several hundred volts AC if all is OK. Measuring between either yellow wire and the yellow-green center tap you should get about half of the previous reading.

Xfrmr still not complaining? Hope you're wearing sneakers and standing on a rubber mat. Put one hand in your back pocket and feel the xfrmr shell. Old radioman trick, that's how they got to be old, not making a complete circuit across the heart. Not hot yet, good. Test the other windings: the filament winding to the rectifier should be 6 or 7 volts, the winding for the heaters of the other tubes, if they are working, 6 volts or so, in that ballpark.

If all is still OK, leave the power on for about half an hour but watch it carefully, don't leave it. Transformer should only get a little warm to the touch in that time if it's not shorted.

As stated before, after getting tubes sorted out, I wouldn't fire it up again without replacing caps, especially the 'lytics. And checking all components, resistors, inductors, in the power supply. There is always the possibility that something shorted and took out the rectifier tube. Next time it could take out the transformer if not fixed first.

Good luck and have fun!
Reece

[JGlenn]

Hey, thanks for the advice on testing the power tranny. I'll have to get some new line cord as the original is still on it without a cordcap and feels about as brittle as dry spaghetti. Then I'll give it a try

[Reece]

One more item, after cord is replaced, first power up should be through a dim bulb circuit: easiest way is to take a cheap extension cord and separate the two wires from each other for a few inches in the middle of the cord, then cut ONE of the wires and insert a standard light bulb socket. Now you have a bulb in series with the line so that you are cutting power to the receptacle end of the cord. Plug your radio into the cord and put a 60 watt bulb in the socket. Plug in cord and turn on radio. You'll have lower voltage now at the radio, and the bulb will take the hit if the radio is shorted. If the bulb lights up bright, your xfrmr or radio wiring is shorted. If the bulb is dimmer than normal, all is probably OK at this point. Next try a 100 watt bulb. Bulb should also be dim. You can leave it this way for a while, checking transformer for "fever." If all is well, then go through the procedure previously outlined.

Another thing to check on the transformer: where the wires go into the transformer housing: have a look at their condition. If they have iffy insulation at that point they could short. You can temporarily unsolder each wire and slip a piece of shrink tubing over it and stuff it up into the transformer as far as possible.

Some of this might look like belt and suspenders and maybe it is, but if your xfrmr is still good, you sure don't want to risk it and have to search for another one. I always like to be plodding and methodical around these old sets.

Reece

[compucat]

I have a 1937 model 610 Philco tombstone, the same radio just a year later. Definitely change the electrolytic caps. They are the old wet cell type and will not be working by now. I left the cans in for appearance sake and wired new ones beneath the chassis. Also, replace those two bakelite blocks under the chassis. The contain paper caps.

I have had my restored set in daily service for two years now with no problems. This set is well suited to daily use and the tone quality and sensitivity is excellent. This is a great performer on shortwave and the dial is remarkably accurate.

[JGlenn]

where did you get the bakelite blocks? or did you just replace them with modern caps ?

[Philcofan42]

Originally Posted by JGlenn

where did you get the bakelite blocks? or did you just replace them with modern caps ?

Just replace them with modern caps. That's what I did on my 40-160. I used safety caps from Just Radios. It's a tight fit to get the safety caps into the block, but it can be done. I wanted to keep the block to reattach the power cord. I was even able to install a grounded three prong cord instead of the old two prong. There are different procedures for removing the resin and old caps from the block. I dug it all out with a solder tool and it was pretty easy. Just be careful because bakelite is fragile. It was my first recap and it went pretty much without a hitch. Turned out to be a great radio, that gets a lot of use. I attached a chart on the bakelite blocks so you can see what's what. It's copyrighted 1937 so it may not cover your radio, but it will give you some idea about the blocks connections.

[Reece]

Re: the bakelite blocks: some heat them a little with a hair dryer just enough to loosen the innards so they slide out in one piece, like getting ice out of the tray. No need to refill with any material once you put the new cap inside.

Reece

[marty59]

After you've gutted out those bakelite blocks there will still be some sticky residue remaining. Bug and Tar remover or some laquer thinner followed up by soap (dawn) and some running water and a soft, old toothbrush at the sink will clean 'em up good.