[Ron Ramirez]

It was inevitable.

I'd read the horror stories about Philco 89 sets, but I had never experienced any of the difficulties.

Until now.

A complete chassis and cabinet restoration of a Philco 89L from 1933-34 was in order. The cabinet refinish went well, and it awaits its finished chassis (photos forthcoming when I finish this roll of film).

The chassis was quite another matter. It's standard operating procedure for me to not only replace all of the paper and electrolytic caps and out-of-tolerance resistors, but also to go ahead and rewind the primaries of those pesky RF coils; since if they aren't bad already, they will be sooner rather than later.

Having done all that, I fired it up for the first time.

Nothing.

Found the primary of the 2nd IF was open, and replaced it with another.

Now the set would sometimes tune in stations, weakly; but more often than not, it would just squeal.

After spending most of the day tearing out what hair I have left, I suddenly found that sometimes, when I touched the antenna lead to the grid cap of the Type 36 det-osc tube, the set would mysteriously come to life for a little while.

AHA!!! Having read about the trouble with the oscillator circuit in Philco 19 and 89 sets, I had already reduced the Type 36 oscillator cathode resistor from 15K to 10K per a Philco recommendation; but 10K wasn't enough.

What I ended up doing was trying different Type 36 tubes until I found one that would work well in the circuit, and I also had to further reduce the Type 36 cathode resistor to 7,500 ohms. (That suggestion is made in Ghirardi's "Radio Troubleshooters Handbook.")

That did the trick, and now the set comes right on and plays when turned on, without any "finagling" (sp?).

All it needs now is a volume control replacement, and it's good to go and ready to launch.

WHEW!!!

[Ron Ramirez]

PART 2

Last night, the 89 seemed to be doing OK - until I pulled the trigger on my soldering gun to do something else, at which point it quit working again!

AAAARRGGGHHH!!!!!

To make a long story short, I robbed an oscillator coil from my "shelf queen" Model 32B (same basic circuitry, made to operate on 32 volts DC). Cooked it with a hair dryer, then rewound the open tickler winding. Installed it in the cantankerous 89 and...BINGO.

It came right to life, loud and clear. It passed my "stress test" of being picked up an inch or two from the bench and dropped repeatedly. I turned the soldering gun on and off; other things in the work room on and off; it kept on playing, rock solid.

I'll let it play the rest of this evening, and if it doesn't cut out anymore, THEN I will declare victory.

Lesson learned: From now on, I plan to use heat to bake EVERY Model 89 oscillator coil I encounter. I am convinced that doing so will help avoid such problems in the future.

[Chuck Schwark]

Ron,

Mind if I condense and edit the "89 From H**l" posts and turn them into a Service Tip on my site as well as having it here?

[Ron Ramirez]

Chuck - check your e-mail.

All - VICTORY AT LAST!!! The 89 kept on playing this time...it's back in its cabinet now, waiting for its owners to come pick it up, and it still works! Woo hoo! 8)

[Chuck Schwark]

...and another PITA 89 out the door.... 8)

[Ron Ramirez]

Here's how that 89L turned out:

[Image: http://www.philcoradio.com/images/phorum...l_1934.jpg]

Not too bad...considering it took a LOT of work to get it to this point. (For some reason, it looks lighter in the photo than it actually is.)

[Chuck Schwark]

The Model 89 from H**l
has now been immortalized on my site in the Service Tips section, along with a couple circuit diagrams, kindly provided by Mr. Philco.

The Philco Repair Bench - SERVICE TIPS

[Ron Ramirez]

It's happened again...different 89 lowboy this time...same trouble in the oscillator coil. And this one came with a Type 77 det-osc tube as standard equipment (somewhat more reliable than the older models using a Type 36 in this position).

The hair dryer was not effective this time; I had rewound the cathode (tickler) winding after hitting the coil with the hair dryer, but all the set would do was squeal. Amazingly, when I put the test leads of my DMM in parallel with the tickler winding, the set would work properly.

So this time, I pulled the coil, along with coils from my 19TX and the leftover coil from the previous 89L, completely unwound all three windings on each, and baked the forms in the oven for an hour at 225 degrees.

Sealed the forms with lacquer, then proceeded to completely rewind one of them and reinstall it in this 89L. I'll rewind the other two coils later.

It seems to have worked; at least now the locals are coming in loud and clear, without the squealing it had previously. I'll know more tomorrow about how well it works, and if it is working on the lower end of the band as well - all our locals are on the high end, and it's hard to pick up anything in the workshop area of my basement.

Edit: I aligned it this morning and all went well for the most part, although the IF broke into oscillation at one point; that turned out to be a very simple problem which is now corrected. Also, I had to recone the speaker, so now it sounds really good in its cabinet. But it is now apparent to me that unwinding all of the windings from 89 oscillator coils, baking the forms, sealing them and then rewinding (with new wire) is going to have to be standard operating procedure from now on in order to assure a good, stable repair on these sets.

[fenbach]

What gauge wire to rewind the primary?

[morzh]

I use 42 - good fit all type.

[Radioroslyn]

I kinda like 38G it's a little easier to work with. Both are pretty small.

[madsowry]

Would this procedure work for a mod.18 code 121 with the same symptoms?  Oscillator coil continuity is good and ohms are right on for secondary, primary ohms are a little high.  Radio starts getting local stations  very weakly then fades out and stops oscillating.  Could it be a leaky winding somewhere on the coil?  Thanks

madsowry

[Arran]

It could be a bad resistor in the oscillator tank circuit as well, I've had sets that would do that, the oscillator would quit working at one end of the AM broadcast band. However I believe that if the primary winding is reading high in DC resistance then corrosion has probably already set in and that winding will require replacement.
Regards
Arran

[madsowry]

Thanks Arran    The pri. of the oscillator coil is supposed to be 3.4 ohms for 17 turns.  I rewound mine with smaller wire (40 ga.) at 20 turns and got 7.4 ohms.  Is that too much? I will check those resistors in that circuit.  Thanks again

Dick