[gary rabbitt]

Hi everyone,

I have started to work on a Philco model 89 code 123 with the SW band.
http://www.nostalgiaair.org/PagesByModel...013877.pdf
Having a little trouble with one section as far as verifying the wiring. It has not been worked on before, except to install one filter.
Anyhow, the diagram shows it using a #77 tube for the detector/osc. The set has a #36 tube installed. The #36 was used on a regular model 89 I see.

I thought that someone my have installed the earlier tube in the set, but that would be impossible as they are two different bases. The socket are stock and have never been changed.

The question is, could this have been an earlier run of the 89 code 123 but still used a # 36 tube?

There is also a bakelite block that doesn't seem to connect where it should, perhaps because of the older tube?
Diagram calls for a 3515-G block, (part 9) and the one installed is an 8774-B block. (I have the block pages bookmarked)

If it is an "early run", I may have to refer to the regular model 89 in those areas I guess.

BTW, the chassis is metal stamped with X96670, under the chassis is rubber stamped 38-1034

Thanks for any help on this set.
Take care,
Gary.

PS I have heard about the Super 89 mod as a workaround for the original 36 tube, but I think I will pass,. This is a 'customer's set' and I don't want to get into it any more than I have to
I will read up on the mod though.

[Texasrocker]

Hello Gary,
I did a quick-look over at nostalgia-airs tube diagrams. If their tube substitute info is correct, the #77 tube & #36 tubes wont interchange.
Since your sockets orig, perhaps replacing the #36 w/ a #77 tube will get you going.

If you have a GE tube manual, check the pinouts of the orig #77 tube socket against the diagram in the manual, to that of the schematic. Sounds like someone tried to retrofit a #36 where it doesnt belong?

Substitute tubes for the #77 are listed as a #57 tube, or a 6C6. If you have a spare #57 or 6C6 around, you could check the tube manual diagram and sub them in as a reference.

Best of luck with your restoration!!

[Steve Chambers]

Hello Gary,
I did a quick-look over at nostalgia-airs tube diagrams. If their tube substitute info is correct, the #77 tube & #36 tubes wont interchange.
Since your sockets orig, perhaps replacing the #36 w/ a #77 tube will get you going.

If you have a GE tube manual, check the pinouts of the orig #77 tube socket against the diagram in the manual, to that of the schematic. Sounds like someone tried to retrofit a #36 where it doesnt belong?

Substitute tubes for the #77 are listed as a #57 tube, or a 6C6. If you have a spare #57 or 6C6 around, you could check the tube manual diagram and sub them in as a reference.

Best of luck with your restoration!!

A 57 won't work. 2.5 volts on the filament. 77 or 6c6 would require a socket change. Maybe Ron or Chuck can explain the documentation mystery.

Steve Chambers

[Ron Ramirez]

Okay, here we go...

March 15, 1933: The AM-only Model 89 was modified to add the "police" band (1.5 to 3.2 mc). A fourth control was added between the tone and volume controls - this was the band switch, which was combined with the set's off-on switch, the off-on function being removed from the volume control. At this time the 89 chassis became Code 123.

The new 89-123 still used a 36 tube as an autodyne mixer-oscillator.

The change to a 77 tube did not occur until September 1, 1934 - during the 1935 selling season. The 89 chassis remained Code 123, and would remain so through the end of its production around early spring 1936.

Yet Bulletin 146B, covering the 89 Code 123 with a 77 tube, was not published until September 1935, one year later!

Don't ask me why - I wasn't around then. Philco was not consistent with its code number changes; just take a look at Model 60, which underwent numerous changes during its three year run yet remained Code 121 throughout.

[Ron Ramirez]

I forgot to mention: A properly restored, stock 89 can work just about as well as one does with the "Super 89" mod - IF you take the time to bake the oscillator coil in your oven for about 30 minutes at 200 degrees F, then clean off and rewind the outer (tickler) winding. This is critical. These oscillator coils are very prone to moisture absorption. Also, be sure you replace the 15K resistor in series with the oscillator coil tickler winding - part (10) in Bulletin 146 - with a 10K or even 8.2K unit; 1/2 watt is fine. In addition, you must replace the capacitor in parallel with this resistor, part (8) in Bulletin 146, with a new 680 pF mica or NP0 ceramic cap. The original was 700 pF and is a paper-wound cap inside a bakelite block shared with a .09 uF cap connected as a B+ bypass. 680 pF works fine as a replacement for the 700 pF cap. This will cure most, if not all, of the ills associated with Model 89.

[gary rabbitt]

Hi guys,
Thanks Ron for that explanation. The 36 tube was original as far as I could see, but I suspect the Riders diagram was of the later model set with the 77 tube. No one has tried any mods on this as far as tube socket changes, and I really don't want to start changing things on this set.

I know about the model 60 and it's chages. I just did one, it was a Run 11 model. Had to do a little decyphering but I made out ok on that one Your resources on that model helped immensely. Worked great when I was done.

If the 89 works, I probably won't bother with the rewind of that coil. But I wll keep it in mind if there are problems. I will have a look at it though to see what it's all about.
Ron, is there a place to view the bulletin 146, or do I have enough info from your post to do the repairs?

Thanks a lot, and take care,
Gary.

[exray]

Gary,
In Rider's you'll see some additional pages addressing the oscillator issues with the 89 along with recommendations. I think you'll find these pages on NA if you look thru the various listings. Its a sore point on this model but is easily fixable.

Adios,
Bill

[gary rabbitt]

HI Bill,
Good to see you

I have a set of Riders, so I will look in related pages for the osc coil issue. I didn't see it off hand with the model 89 (123) diagrams.
Waiting fo the guy to bring some electrolytic caps so I can at leat try to power it up. I have some 10/450 on order.
I was looking for an excuse to stop work for a day or so on it, so I can get some yardwork stuff done.
Take care and see you later,
Gary.

[exray]

HI Bill,
Good to see you

I have a set of Riders, so I will look in related pages for the osc coil issue. I didn't see it off hand with the model 89 (123) diagrams.=

Its in there. All about drying the coil and resealing it and fudging the cathode R values. That was a CENSORED after a year or two of coming off the assembly line. Imagine 70 years later!
89 is a good radio but they seem to require some intuitive savvy to get them back to par.

[gary rabbitt]

Hi Bill,
I found the data, thanks.
I tried to power up the set last night, nothing at all. But I seemed to have a very high voltage on the B+.

Did some checking and founf the wirewound 2 section resistor to be open.
OK, it liiked like broken wires on the form, but that was just string wrapped around.
Still, under the string, I was able to pull a couple of pieces of the wire from the resistor. Here is the part. (Chassis parts 23 and 33) The wire ends had tiny blobs on them where they burned apart.
[Image: http://antiqueradios.com/gallery/d/90514-1/89res1.JPG]
.
.
I think the spec on this was 235 Ohms and 32 Ohms.
[Image: http://antiqueradios.com/gallery/d/90516-1/89res2.JPG]

I assume I can install seperate resistors, but about what wattage whould I use on this. I have some 2 through 10 W resistors I can make up an substitute unit.

Was there any reason Philco used a wirewound part in this location?

Hopefully it will power up, as everything else looked ok.
Thanks,Gary.

[exray]

Hi again Gary,
You can estimate the current thru the resistor from the schematic and calculate the wattage. Its not terribly high. They used wirewound so as to obtain the precise values that weren't available in a normal carbon resistor.

[gary rabbitt]

Thanks BIll,
I installed a couple of 4 watt parts , and not I can get the set to receive. The resistors didn't get hot.

Today, I am going to recheck the remaining dogbones, they all have been way off in this and other sets.
The symptom is, the set will receive from 1600 and tune down to about 1200, then tuning a little more will stop receiving.
I doubt it's the tuning cap plates, but I will still check. It does not stop abruptly, but 'fades' at a certain point. I suspect there is a low pf cap that may be leaky. The SW band does the same thing, receive on the high end, then fades off.

The issue about moisture in the osc coil, I wonder if this would be a symptom? I'll probably remove that also and have a look.

Well, that''s the plan for today, at least the set is somewhat working.
Will let you know what happens.
Gary.

[exray]

Yes, I'd be suspicious about the coil. If the tuning cap sections check out ok for shorts that would be the next place I would look.

[Texasrocker]

Hello Gary,
Since you have the set working now, and receiving some stations, have you checked the alignment adjust using the chassis adj compensation condensers? The orig mica in them could be bad, or dirty,shorting internally? I took another look at the Riders schemat you posted originally, and the 89 has a intermediate freq of 262 khz?
If your RF gen signal goes that low, check for alignment on the compensating condensers with 1st harmonic. Or 2nd harmonic at 524 khz, or 3rd harmonic at 726 khz. Peak the compensating condensers for max vol by ear according to schematic. If you dont have a freq counter onhand to be precise on your RF gen output, a digital am dial receiver can verify your exact RF gen signal output at 262 khz by ear, listening for the harmonics carefully.Use low-output on your RF gen as possible to keep stray-harmonics low as possible.
If your main-tuning condenser is working correctly, and clean of debris,with no shorts,you should be able to tune the set fully once the chassis compensation condensers (3) properly aligned?
Read again carefully on the compensating condensers adj. for the mod 89 on Riders page 7-78.
Just tryin to help if I can, for proper alignment on your set if accidentally overlooked. Best of luck on your Philco restoration!

[gary rabbitt]

Hi Randal, Ron and everyone
Thanks for the tips.
I have been having fits with this set the last few days.

<<EDITED>> I have just read the Philco from He** text about a cantakerous model 89, symptoms sounded like this one.
I had already tried the heating of the coil a few days ago with no luck.

A little history and my current situation.

(Even though this is the AM/SW set which is a code 123, I am using the early diagram for the AM only using the # 36 tube. The bakelite blucks match up with that set, I have recapped according to their original part content.)

OK I was able to receive stations, but only on the high end. Took the grid cap off the 36 tube and it would receive all the way across the band! Ooooo K.

After about 10 minutes it would just stop receiving at all. I have a sig generator and when it was receiging It aligned very well. Tuning cap is very clean. Mica sheets in the trimmers look clean.Receiving lots of stations at night.

Ok, next day, fired it up, received half the band again. (I reconnected the grid cap)After messing with it as far as looking for a loose connection which I didn't find, the thing would oscillate on the high end of the band! Receive well below about 900khz. Tuning higher it would start to squeal. Grounds good, tube shields in place the works.
Today squeal still there, tried to realign, no change.

What could be next? This afternoon for some reason, the set stopped working totally. The stages past the IF was ok, audio had strong buzz when tube cap touched.

Last resort, I pulled the oscillator coil that is widely known to cause issues.
Now I am not positive, but I think that one of the hair wire leads was broken near the terminal. No problem. But when tested for continutiy it showed open.
I connected one lead to one end of the winding (This is the small winding on the outside of the coil) and I probed on the wires that were wound. It had continuity until I got about halfway across, then it was open. (See photos)
So, the break in in the winding itself. Time to do a rewind I guess.

Here are the questions I am dealing with right now.

***Is this the winding that needs to be rewound after the "baking in the oven" procedure? As seen in the photo it's the smallest winding.

***How many turns should it have? I believe I have the same diameter wire on hand.Looks like about 29 to 32 turns.

*** Is the winding just one layer?

I assume there are no taps on this winding. The diagram shows just a small coil on the Cathode of the 36 tube.
NOTE: I had measured this winding when I first started and it measured 150 Ohms. The spec says 5.25 Ohms.
Probably part of my original problem.
Here's the pics.
[Image: http://antiqueradios.com/gallery/d/91130-1/Phil89a.JPG]

[Image: http://antiqueradios.com/gallery/d/91132-1/Phil89b.JPG]

I really hate to give up on any set, but this one is getting the best of me. It's for a customer/friend and I like to get it out of here ASAP.

Thanks for everyone's help.
Gary.