Have used many of the techniques learned so far but am now at a dead end with a Philco 89. Not sure what to do next.

The easy things are done (i.e. reviewed, caps replcd, tubes tstd, main rplcd). I have data to offer only. Not able to make sense out of results and don't have a compass.

This is the model with the #36 detector... http://www.nostalgiaair.org/PagesByMode ... 013876.pdf

I apologize if this is a boat load of data, but it is all I have at this point....

Values are taken as instructed in the schem. (i.e. plate to cathode etc....)

HV = 350 and 40 ohms to ground
= 235 and 40 ohms to ground

Rect filament = 4.5v target 5.0v
Rect plate = 360vac target 350vac
Other filaments = 5.8v target 6.3v

Ampl:
plate = 192v target 235v
screen = 230v target 245v
grid = .60 target .15v
k = strange activity, can not value target .15v

2nd Det:
plate = 100v target 175v
--- chgd 27 & 39, 67v
grid = 3v target .30v extrmly loud speaker when measuring
--- chgd 27 & 39, .23v no speaker scream remains
k = .17v target .20v
--- chgd 27 & 39, .93v
grid cap to ground - 2 ohms
tracer = no station tuned thru grid cap

IF:
plate 220v target 240v
screen = 67v target 90v
k = 2.5 target 3.5v
tracer = no station tuned thru grid cap

Det:
plate = 150v target 250v
--- chgd 27 & 39, 155v
screen = 40v target 90v
--- chgd 27 & 39, 52v
grid = 7.4 target 7.5v
k = 7.4 target 7.8v
grid cap to ground - .73 ohms
tracer = station tuned thru grid cap
= no station tuned thru plate with audio setting

RF:
plate = 200v target 235v
screen = 66v target 90v
grid = 2.45 target .3v
k = 2.1 target 3.5v
grid cap to ground - 4.5 ohms
tracer = station tuned thru grid cap

Thank you for any help you can give.

I am mostly concerned with the low voltages at the Detector (which is actually a Converter or Mixer/Oscillator, I never understood why they called them Detectors). Anyway, first a question and then a suggestion.

Did you replace the capacitors inside of the Bakelite Blocks? They are paper/wax caps too and need to be addressed.

Now, I would suggest tuning the dial on the radio to approximately 600 KC. Then with another really close radio (maybe a little transistor portable set right next to the 89), tune it to 600+260=860 KC/KHz. See if as you tune around you hear a signal from the 89 in the other receiver. If you hear something you can tune the 89 a little to make sure it is the source of the signal.

You are trying to determine if the Local Oscillator is running.

Curtis Eickerman

The 89 is one of the early Philcos with lots of coil trouble, due to corrosion of the windings. Check the windings of the oscillator and RF coils for continuity, and rewind anything which is open.

Hi,
You might not get an open reading, even thought it may be corroded.
The corroded spot still may be connected just enough to get a reading, but off spec.

Look around the small winding, seperated by a plastic strip. You just might see green corrosion with a high powered magnifier.

Hello and Thank you for all of your replies! Having read a few of the threads re Philco 89, it has earned a reputation.

Well Doc, I am happy to be on a mission with you again! Thank you.

The caps in bakelite blocks were not replaced. Didn't know what they were. I quess I turned the blind eye to them! That is a lesson learned.

Repacked new caps into 27 & 39 just now, tested values and added appreciable changes into the orig post data log.

To complete the remaining blocks, here are some questions re them:
5 - the rf cathode terminal actually is connected to the can (7) thru one of the white-black tr. shown on the schem drawing of the can caps. It too has a .09mfd rplcd w .1 mfd. 5 shows connecting to cathode if I am reading it correctly
- block 5 is currently connected to 6, 43 and tuners

8 - spec .0007mfd, have a 68pf, good to go?

26 - spec .00011mfd, nearest I have is a 150pf, too much?

30 - can't identify what values on the schem

45 - no block or mounting hole in chassis, will jump .05mfd to 44 & 46, good to go?

Haven't checked any of the coils yet. Do you recommend replacing the remaining blocks, checking the coils or firing up the transistor first?

I am a little short on time at the moment, and can't say I am exactly understanding this. I will take a look later if I get a chance. For the moment I would duplicate existing wiring.

.0007 uF would be 680 pF.

For 26 that would be fine.

I don't know why they didn't seem to identify this one, but I think it would be another 0.015 uF cap.

45 is actually in parallel across the field coil. I am not sure what you are saying. Was it missing? It is not critical if it was. They sometimes used these to resonate the field coil at 120 Hz to reduce hum. It will still work reasonably well without it if necessary.

I think it would be a good idea to do the ohm meter check of the coils since they are a known problem. I would not worry about turning the radio back on until you have replaced the caps in the bakelite blocks. We already know it is not working. After that is done, assuming no obvious coil faults, then it is time for the Local Oscillator test.

Curtis Eickerman

Update:

Powered up to perform the transistor radio testing and there is a station tuning in on the 89. If the volume is turned up alittle below the lowest there is loud motorboating.

Motorboating means more caps to go generally

Otherwise pretty good news. Maybe you have escaped the coil plague.

Curtis Eickerman

That would be nice!! But I am not holding me breath!

edited my sloppy explanation of cap block 5. sorry.

here is copy:

5 - the rf cathode terminal actually is connected to the can (7) thru one of the white-black tr. shown on the schem drawing of the can caps. It too has a .09mfd rplcd w .1 mfd. 5 shows connecting to cathode if I am reading it correctly
- block 5 is currently connected to 6, 43 and tuners

Sorry, this probably makes more sense when you can actually see the wiring in the chassis (which they do not show in the documentation), but I think the connection you are following is actually a ground connection between these various items.

By the way, for what it's worth, I was reading the page on "Correcting Intermittant Operation" and it sounds like the model 89 with the 36 tube has a "lot" of ways for the Local Oscillator to not work properly

So, I am anticipating problems in that regard.

Curtis Eickerman

Sorry Doc, I got pulled away yesterday.

I understand your last post.

Chgd block 26 just now, still motorboating.

Block 5 - maybe the connections are not important, but just in case here is an idea of how they are:
-the block has three taps that could be described as 1- ground tap 2 - middle tap 3 - end tap.
tap 1 - two wire connections, connection to tuner antenna and tuner detector
tap 2 - one wire connecting to the junction of a 99,000 ohm res and a 1,000,000 ohm res
tap 3 - one wire connecting to schem #2, then wire continuing and connecting to the junction of #21 and a wire to #18
- there were two caps inside, one has a large "10" sticker on it and the other is not quite legible and may read "40"
- block 5 is listed as .09mfd. The value is listed once and not twice like #26 & 39. Would you recommend installing a .09mfd between tap 2 and tap 1 and then another .09mfd between tap 3 and tap 1?
or
- Would you recommend connecting one .09mfd to tap 3 and 2, and then to tap 1?

Block 8 - two values are listed .09mfd and the 700pf caps
- Couldn't locate a 700pf cap, should be able to acquire it monday
- Will detach, rplc and suspend the .09mfd cap connections for now in hopes it is the cause of the motorboating, but I can not tell if the .09mfd is connected to R10 or to the ground from 6, 18, 23 etc. on the schem. How would I identify which is which?

Block 30 - this is the one that has no values on the schem. There was one cap inside. No marking was legible.
- maybe the connections are not important, but again, just in case, here is an idea of how they are:
- the block has four taps that could be described as 1- ground tap 2 - middle tap next to ground 3 - middle tap 4 - end tap.
tap 1 - two connections, connection to output tube terminal 1, and, ground of mica cap
tap 2 - three connections, wire to 2nd detector plate, a .01 mfd resistor (that appears may have been added) which connects to resistor 31, and, other end of mica cap
tap 3 - one connection, wire to output tube terminal 4
tap 4 - two connections, one to 99,000 ohms resistor, wire to middle tap of schem #43

The 89 is still tuning in stations at very low volume (higher volume causes loud motorboating yet)

Thank you.

Anything connected to the ground terminal might connect to anything else that has a ground. So I would just put those back as they are currently.

Unfortunately, according to the schematic, block 5 actually has just 1 cap (.09 uf and 0.1 uF would be an OK replacement) and 1 resistor (unknown value) or maybe it was a weird combination resistor capacitor device since they don't list the resistor (at least I could not recognize it in any of the blobs under the resistor heading). The only connections would be to ground and to pin 4 of both the 44 RF tube and the 44 IF tube.

The block 5 connections you are describing sound like Block 7 connections. One sounds like the capacitor connected to 21, and the other sounds like the capacitor connected to the junction of 41 and 42. So the question is, does block 7 actually have all 7 capacitors in it, and are they going where they are supposed to? I am wondering if they are using block 5 for them.

If so, block 5 may no longer be doing the cap and parallel resistor job at all. So, it comes down to what components connect between pin 4 of the two 44 tubes and ground (needs to be one cap and one resistor in parallel somewhere).

680 pF standard value is probably what you will have to use.

I think the only thing you can do is follow the cap wiring and see what components it is connected to. There is no way I can tell from here.

This is another weird one. The capacitor that connects between pin 2 of the 75 and pin 4 of the 42 is identified as 30 and should probably be 0.015 uF. This is the capacitor between tap 2 and tap 3 below.

Tap 4 seems to just be a tie-point to connect 41 (99K resistor) to 43 (tapped power resistor).

Curtis Eickerman

Thank you.

Re: connections between pin 4 of 44's:
- 44 output pin 4 is wired direct to 44 rf pin 4
- 44 rf pin 4 has two connections, wire wound resistor then to ground and, wired direct to can 7.
- all of the 5 wires going into can 7 have new caps per 'Figure 3 - Internal Connections Filter Condenser'
- it appears then that with the can 7 cap and the wire wound resistor located at 44 rf pin, these actually accomplished the function of block 5 of the schem

Yes, that resistor was the missing piece (identified as being in Block 5 on the schematic). I am assuming it is somewhere in the 1k to 10K range.

Sounds like in production they swapped some connections between block 5 and 7 which leads to a lot of confusion.

Curtis Eickerman

I will trace thru to see which one was switched.

I really hope this makes sense.....

Of the 5 connections to caps located inside can 7:
- 3 physically match the schem,
- one was to be performed by block 5
- and the last was to be performed by one of the two functions of block 8 (plates to ground)
so,
the two that were intended to be performed by can 7, but are not, are:
- junction of resistors 41 & 42 to ground (physically this connection currently runs to block 5)
- 18 & 19 to ground (physically this connection currently runs to block 5 also)

For the 5 caps listed in Figure 3, and, after accounting for the three that are correct, there leaves a .09 mfd and a .05 mfd cap that was intended for the connections that are currently running to block 5.

To complete block 5 (and can 7), would the .09 mfd correspond to the 18 & 19 to ground and the .05 mfd correspond to the 41 & 42 resistors?

Maybe we can talk about block 8 in the next post so it is not more confusing than it already is!

Your description sounds right, which is confusing if you try to follow the references on the schematic which are different.

So, I am thinking we may need actual component designations like R1, R2, R3... and C1, C2, C3... that are not based upon the "blocks" then go back and identify which resistors or capacitors are in which blocks. For example, saying that C1, C2, C3, C4, C10, C12 are in Block 7. Having a "7" that shows up in 7 different places is pretty useless when trying to point out a particular component on a schematic (expecially when some of them are identified in the schematic as "5").

Otherwise there will be no way for me to point you at a particular component without posting a picture every time (not real practical).

Curtis Eickerman

Agreed!

What do you use to make the drawings you have made?

You have seen what I use!! Professional in all aspects hey?!

The only one I made looked like an owl sitting in a tree!

I took a crack at it with Paint. I had to guess a little because some of the values in the table are not readable.

Curtis Eickerman