[Guest]

Hello everybody,
I just picked up this Philco hi-fi and was wondering if anyone new anything about it. The model number is F-1902-121. According to this sites age chart it was made in 1958. Everything works on the unit but I'm in the process of replacing some tubes to resolve some issues I've noticed with the volume and "bass" level.
It appears to be a mono set up with a two-way speaker design. Here is a pic of the unit and hopefully someone has heard oe seen one of these before.
Thanks

[Chuck Schwark]

I recognized it, but not sure what you're asking, since you already know the year and model number. ??
Typical radio-phono console of the era. Looks in great cosmetic shape. BUT! Don't plug it in anymore until it's restored with new electrolytics and probably leaky coupling caps. Replacing any out of spec resistors (+/-20% max of nominal value) is also a must. You can terminally smoke the power transformer, etc.

[Guest]

Thanks for the response. The only issue I can hear is that the volume will decrease after a few minutes of playing and as I turn up the bass knob the volume cuts off. I've ordered a 6AN8(phase inverter) tube because the original was very weak. I'd like to see what difference that makes. So even if everything seems to be OK you still recommend a complete check-up? I'm still learning as I go as far as "vintage" tube gear. How difficult is it going to be to remove both chassis.

[Chuck Schwark]

Yes. You are living on borrowed time without a restoration. Your problems are one of many of the common ailments of vintage electronics.

Forgot to add above to make sure your tubes test good, besides the normal cap/resistor restoration.

Chuck

[Ron Ramirez]

In addition to Chuck's excellent comments, I would like to add the following.

Too many people who are getting into this hobby or related fields, such as the restoration of vintage guitar amps, have the mistaken notion that replacing all of the tubes in the unit they are working on is a cure-all for everything. It isn't, folks! Here is the reality of what happens when you replace every tube in a radio, vintage guitar amp, or whatever:

1. You are spending money unnecessarily.
The chances are very good that most, and often all, of those tubes are still good! If you replace every tube without checking the old ones first, you are probably just wasting money.

2. You are driving up the cost of replacement tubes and, therefore, hurting the rest of us who know better.
This sort of thing is already happening with tubes such as the 35Z5. The shmendriks who insist on plugging in an old radio without first replacing electrolytic capacitors often end up blowing the 35Z5 rectifier sky-high. So, since there is a finite supply of 35Z5 tubes, the prices begin to go up. Supply and demand.

3. You are adding to our landfills for no good reason.
There is no good reason to toss out good tubes - especially if they are types that are no longer manufactured. If they test bad or are otherwise known to be bad, then yes, toss them, But don't throw them away if they are still good! Test them first!

Remember: It is the failure of the paper and electrolytic capacitors that causes the vast majority of the problems in an old radio. These must be replaced first before doing anything else if you expect that old set to last very long.

Rule of thumb: Replace all paper and electrolytic capacitors first. Check resistors and replace any that are not within 20% of rated values. Test the tubes and replace only if necessary.

I am not directing these comments to anyone in particular. But I do feel that everyone who is new to the hobby should keep these things in mind.

Sorry for the rant, but I felt these things needed to be said.

[Guest]

That's great advise. At this stage in my experience with tube gear I appreciate any pointers I can get. My next step is going to be removing both chassis and have everything checked out.

[PTurney]

Ron,

I could not agree with you more, in fact this whole subject is a pet peeve of mine. I have literally hundreds of radios and I rarely if ever need to replace a tube. Most of my sets, even those that are restored, just sit on the shelf for most of their life (as I only have time to listen to a fraction of them), so why on Earth would there be a need to put new tubes in such sets? In the unlikely event that a radio I choose to listen to has an unusable tube (a fact that I'll record when I restore it) I'll swap the tube with one from some other shelf queen at that time. There's almost never a need to take a NOS tube for it.

Shot-gun replacement of tubes is an insane practice. Unfortunately I see it often taking place at various meets, where someone will buy an old set and then wander over to the tube seller to buy a set of new tubes for it...

Paul

[codefox1]

Couldn't agree more. Until the filament is open or the vacuum breeched, there's always hope for an old tube. I have had some limited success in running a tube for a while with above normal filament voltage until the getter absorbs gas. This I do on my Hickok 539 tester. I'm not talking about ancient thorium coated filaments, but more "modern" types. I know this is not supposed to work, but sometimes it does.

And microphonic tubes may function just wonderfully in other roles other than audio. And even dual heater tubes with one filament gone might be OK where you only need half a tube to get the job done.

In any case I do try to save the tube base on any duds, and can build adaptors to use whatever else I have on hand in the way of tubes and sockets to make a sub without changing the original chassis. (I.E. you can make a 35W4 sub for the 35Z5.)

[Don Lind]

Regarding ratzo's question, audio output tubes and/or coupling caps are likely cause of audio fade.
Make sure the bias resistors for the electrostatic speakers are not open. That was a common trouble.
Your VM changer is better than the Webcor Micromix that was also used during that model year. Should clean up well.

Don

[Arran]

I don't think that I have ever bought a NOS tube from any of the vendors, in most cases I can find a suitable used tube to do the job. I did buy some NOS 1629s over fleabay once but that's a different situation, it's isn't necessary to have a good eye tube to make the radio work. In my experience, 9 times out of 10, most of the problems in a radio can be fixed with under $20 worth of condensers and resistors which is much cheaper then a whole rack of NOS tubes, if it is a tube problem it's often a oscillator/mixer tube or a first audio. Fortunately with this HiFi, with the exception of the power output tubes, if a tube is dead or very weak they are easy to find and inexpensive, but test first. Used tube testers are cheap compared to buying sets of NOS tubes, plus it helps you find good used tubes in those bargain boxes of loose tubes you find from time to time.
Best Regards
Arran

[Guest]

I'm trying to find the schematics for the amp on this unit. The only numbers I have are "TP7 0296" and ""F-1902-121". Does anyone know what schematic number I'm looking for? Thanks

[Chuck Schwark]

Your model number is the last number string: F-1902, Code 121.

Chuck