[jerryhawthorne]

Codefox, most of what I have learned was on forums. Yes, I fixed a lot of TVs at Warwick (Sears) after they came off the line. Didn't know crap but when you work on the same chassis it didn't take long. This was while working my way through UCLA and not in anything engineering related. Spent most of career in medical or research electronics. Not fixing, either selling or managing tech support aspects.
I really want the OP to come back and let us help him. I like to see a finish to these types of threads. Not that I can help much but can observe.
Regards, Jerry

[Steve Davis]

The last time Radiola visited the Phorum was 9-6-2012. I hope every thing is all right with him.

Steve

[codefox1]

Yeah, know what you mean. Well, always take the middle road, add when you can, offer alternatives when you feel like you should. If this were an exact science another ten billion people would be out of work.

[radiola]

Guys, thank you for all of your assistance on this. For some reason, I wasn't getting an email when someone posted something on the thread. Is that how it works, or should I just check back? Well, anyway, sorry for the delay. I have continued to work on the set, and it's turning out good. The low volume was in the potentiometer. Using a little electric cleaner spray, I got it back. It still had a hum and slight growl. This one stumped me for a few weeks, but here is the deal: I was in the process of hooking my signal tracer up to it. I first grounded the radio to the tracer. When I did this, the hum and growl went away. I knew I had some kind of grounding problem. Now, this radio has a special loop aerial - it has five screw-type aerial posts on the chassis. I had removed this and was just using my test aerial, which is a long cord which stretches the length of the garage. I hooked that to the first post. The other screw posts I left blank. After I found out it was a grounding problem. I tooke the Philco aerial off the shelf and put it back properly and it now sounds fine. The other sets I have worked on only had an aerial and a ground post, so I didn't see the problem. Suffice it to say it is sounding great. Thanks so much to all who pitched in with advice.

[jerryhawthorne]

Nice to hear back from you! Glad you have it working. Yes, unlike some forums, you need to check the box at the bottom when you are posting, to indicate you want to be notified of any response. I don't know if they have somewhere in the personal set up to indicate an e-mail response as a default for anytime you post. Would be nice as sometimes I forget to check the box.
Time to start your next radio, we all do.

Jerry

[radiola]

Thanks, Jerry. Well, I'll bench test this one and if I notice any hum, I may have to increase that small electrolytic cap a bit. I think it's only a 4uf.

[Ron Ramirez]

OK guys, time to go to the least used part of the Phorum - the part you have to scroll way down to the bottom of the Phorum home page to see - Phorum 101.

http://www.philcoradio.com/phorum/showth...p?tid=4390

Let's go to User Control Panel --> Edit Options.

Under Messaging and Notification, look where it says Default Thread Subscription Mode and make sure that it reads Instant email notification under that. If not, you will not be notified via email when someone posts to a thread you have posted to.

If you have this set as shown and you are still not receiving emails, check to make sure mail from philco at philcoradio dotdotetc. is not going to your spam filter. (Replace dotdotetc. with dot com.)

[jerryhawthorne]

Thanks Ron, I would never have found that without some direction.
Jerry

[Michael Dennis]

Some forums are set up a little differently. I've been on forums where I didn't have the default set to instant E-mail modification. In most cases, checking the appropriate option will get you the E-mail notification each time a post is made to a subscribed topic. Now, having said that*, there are still some boards that don't send a notification E-mail, even tho that option is selected. Fortunitely it does work here on Philco Phorum.

Mike

* An often used phrase. I hear or read it almost ever day and for some time now. Nothing wrong with its use, though. I recall the first time I heard it used, back in about 1974, by Ian McFarland, on Radio Canada International.

[radiola]

Well, perhaps I spoke too soon. On the bench test today, the set is strong for the first fifteen minutes, and then the sound quality gets terrible. You can still hear it, but it sounds the same as those old A.M. transistor radios with a half dead battery. I had a similar thing happen some time ago where it was a gas leak from one of the tubes. Not here-I've changed all the tubes to no avail and checked them as well with a tube tester. I'm hoping the transformer isn't pooping out after fifteen minutes. I laid my volt meter across the large power cap when I turn the set on and I get 245 volts. Fifteen minutes later it's 235 volts. I don't know if that's enough to cause that, but it's all I knew how to do. What think ye gentlemen??

[jerryhawthorne]

I doubt that the 10V drop in your B+ is your problem, but more of a symptom of your real problem. Something down the line is starting to draw more current once warmed up. I would start with some tube substitution, you may have a gassy tube. Just my thoughts. A tube testing probably wouldn't catch it.
Good luck and keep in touch.
Jerry

[radiola]

After receiving your replies, I tested each tube for gas leaks by leaving each tube in the tester at least 1/2 hour. No leaks detected. I have replaced at least half of the tubes with NOS. I may have to order a few tubes to do a complete replacement check. I'm curious. As the power resistors heat up, which would take about fifteen minutes, is that pulling on the power supply? That's just a shot in the dark. I know there is a lack of filtering if one does not use a choke to replace the field coil. Thanks for your help, guys.

[morzh]

Have you measured the current you draw from your power supply? is the resistor rating adequate?

There are many things that could result in the same problem. Say your output transformer warms up and develops a turn short. Or one of your caps....BTW have you recap it fully? Etc? Resistors?

[jerryhawthorne]

Perhaps time to go again back to basics, which I believe in. Turn it on and do the good old center tap touch of the volume control with it turned up. wait until such time as the volume drops, then do the good old touch on the center tap of the volume control again. Is it as loud as when the voltage was high? Is the power transformer hot to the touch? If it as loud as when the set was cold, and the transformer is not hot, I don't believe the problem is related to the transformer and the observed voltage drop at what I am guessing is the first cap before your new resistor added for the field coil. Would be interesting to then going through the whole procedure of cold start, measuring after the new resistor combo for the field coil and see what the voltage drop is. I suspect it may be much greater than before IF the problem exists further down the line. The starting cold voltage should be lower than your previous measurements, just want to see what happens when the radio is warmed up and any change. It will start lower than your initial voltage reading due to the resistors, fine it should, want to hear what it goes to when your radio volume drops.
Remember, I'm no expert!

[radiola]

Thanks for the replies. I'll do that regiment within the next week as time permits. I did recap and resistor check EXCEPT for one cap which comes off the rectifier. Wouldn't it be something if that was it. I didn't change it because it was a blue paper one and obviously was changed once. That's the first thing I'll do, though. Thanks!!!!