Philco 41-285 wiring issue
 

Hi all working to restore my 41-285 Philco console.
Flipped over the chassis to see under the 84 6Z4 socket..to find out there has been some modifications. Running off one of the electrolytics are some soldered in resistors to the 84 6Z4 socket. There was also a pin cut off the tube when remove?
So not sure how to wire it correctly?
I have an 84 tube with all the pins but I wanted to ask if I should cut out the resistors and wire it another way?
And could one of you comment on the correct way it should be wired?
Not so good at reading the schematics..:(
everthing else seems to be normal but this socket.
thanks

forgot to mention
I put an white arrow on the pin that was cut out..not sure why it was done

Check the secondary of the power transformer. One side might be open. Use an ohmeter to mearsure from the center tap to each of the other two taps.

Or maybe one plate of the 84 was shorted and they didn't have another.

I couldn't follow the wiring in the photo.

John

It appears that two diodes (not matching) as well as a series resistor (27 ohms) for each diode have been installed between the plate connections of the 84/6Z4 and the filter cap. These diodes bypass/replace the diodes of the type 84/6Z4 (dual diode) rectifier tube. Perhaps one of the plate pins was cut off of the tube to prevent arcing, if the old tube was gassy.

On a 5 pin tube base, pin 3 is the pin with the widest gap between the pins on either side... so (counting CCW around) it appears that pin 2 is the one that has been cut off... is this correct? Then it is indeed one of the plates. Pin 1 which is the next pin around, is one of the heaters for the tube, but looking under the chassis there appears to be NO connection to pin 1, therefore the tube will not light up. The wire to pin 1 may be cut off short somewhere... you will have to find out where pin 1 was connected and restore that connection. It also appears that there is NO connection to pin 4 of the tube. This would be the cathode of the tube, which would normally be connected to the filter cap, had the tube not been bypassed by the two solid state diodes. This connection would have to be restored as well, for the tube to function normally.

Could you scan in a schematic for the set and post it?

Does the radio function ok with the 84/6Z4 bypassed?

jr

The schematic can be found here:
http://www.nostalgiaair.org/PagesByM...7/M0013417.pdf

I couldn't tell if one leg of the heater was disconnected or if the wire was dark and matched the bakelite.

John

Looked at it again.
The cut pin on the tube has the electrolytic wire and resistor going to it..it looks fried..and that is the pin that was cut.
The other wire and resistor goes from the same source to the pin above.
I put white dots on the pin/sockets..that have no wire going to them.
So maybe with the help of y'all..you can tell me the correct way it was suppose to be wired..I have another tube with no pins cut..and I could give it a go...
Bulbs lite up..but no sound or sign of life when plugged in...this tube was cold when plugged in.
Not sure why such a cludge was done.
any help or suggestions..is so much appreciated!
I would never get these things going without the help of others..thanks again.
Hope you can comment.

Mick

Yeah, Jr_tech is right. They're not using the tube at all and substituted diodes.

John

So is this the number pin out?
Since I have another tube..I was going to cut out the diodes and resistors.
Good idea or bad?
Those diode,resistor points still have the original wires in place.
No wires though on pin 1 or 4 ..as I understand it.
Looking at the schematic..the green wires go to the heater plates. right?
But it looks like there is a green wire going to #5 :scratch2:
I am stumpt to find the correct wires to 1 and 4.

The 84/6Z4 is notorious for shorting out as are the earlier 6X5 rectifiers. All of these tubes are electrically equivalent but have different bases. I had the 84/6Z4 in a 1939 Philco short out on me once. On sets that use these rectifiers I have been getting into the habit of disconnecting the rectifier tube from the circuit and replacing it with a pair of silicon diodes and dropping resistors. That way you can leave the tube in place for aesthetic reasons. If you decide to go that route I would replace the silicon diodes currently in your set with a pair that are of the same type. 1N4007 diodes are the typical choice for this purpose.

I think that you have correctly identified the pin numbers.

I would do a few more checks before cutting the diodes and resistors out of the circuit. Do you have a voltmeter?

1. Can you measure any DC voltage (perhaps 250VDC or so) between the capacitor (+) where the diodes are connected and ground (chassis), when the radio is on ?

2. Pin 5 (still connected) should be one of the heater pins of the tube. Can you measure AC voltage between that pin and ground? If it is 6.3 VAC, you are in luck, and you merely have to ground pin 1 (perhaps to the ground lug on the nearby terminal strip) to get the tube to light up.

It looks like the green cloth covered wires are connected to the PLATES of the tube (pins 2 and pin 3) This will be a fairly high AC voltage, perhaps as much as 500 Volts between the two green cloth covered wires. Be VERY careful, if you try to measure this voltage.

Is the base of the tube charred or is the socket in the radio charred?

jr

reports are in....
Measured DC voltage between cap(+) and diode connections..pin1 is 275-280 and pin3 is 281.
Pin 5 grounded was 5.9 VAC.
ground pin3 was 213AC... ground pin2 was 214AC.... and between the two it was 495AV voltage.
I also ground the pin1 as suggested and the tube lit up..but still no soudns or stations with antenna and speaker hooked up.

So should I replace these electrolytics with new ones and wire them as they are currently?
And proceed to install caps and check along the way?
suggestions and comments....much appreciated

Progress is being made! Can you measure between the + of the cap and chassis ground, and between the + of the cap and it's other end ( - ) The cap should have about 250VDC across it.

jr

measured (+) cap and ground to chassis it is 251VDC.
Measured (+) cap to other side (-) of cap and it was 271VDC

awaiting further instructions......:D

OK it sounds as if the solid state diodes are working ok and producing a decent B+ voltage for the set as measured on the cap. Now this voltage passes through the speaker field coil (part #60 on the schematic) to a second cap (part #27a on the schematic) the second cap should have about 180VDC or so between the + side and chassis ground. If that voltage is not present, it is possible that the field coil is open.

If you can't locate the second cap take another picture that shows a bit more of the wiring, and I can try to spot it.

Does the speaker plug in to an outlet on the chassis or are the wires just soldered to the circuit?

jr

I can almost hear the music! You're making great progress with jr tech's help.

John

ALL RIGHT!!:banana:

I am starting to really follow along. Thanks man.
I think I haver located it here on the drawings...but not sure location in the chassis.
Are we talking about the other bigger electrolytic..since we are talking (+) sides of caps?

Yes, It is the one that you have indicated with the "smilie" face on the schematic. It would be an electrolytic, perhaps a metal can on the chassis, or perhaps similar to the the one the diodes are connected to, under the chassis. Perhaps if you took picture that shows more of the wiring, I can spot it. It could be the one that is right next to the first cap, but I can't tell from the picture what that cap is connected to.

jr

Great.
I will take a few pictures and post them tonight.:thmbsp:
thanks again

few shots in search of next step.

Also forgot to ask..as we looked at the diodes and resistors..there are two lines to two differents pins. One pin is cut off on the tube..so one of the diodes is not doing anything. But was it wired this way with the intent that the tube being used had all pins attached?
So should I use a tube that has all pins?

Could you take a picture that shows the end of the capacitor that is above the one that the diodes are connected to? I think that it is C27 and C27A and the Red and Blue leads that are visible in the picture connect to it. If that is the case the red lead should measure about 180VDC to chassis ground and the blue lead about 100 VDC to chassis ground.

The fact that the pin is missing on the tube is of no consequence YET as the diodes are getting voltage from the blue wires attached to pins 2 and 3. You could pull the tube and still get the same voltage at the first cap (part #62 on the schematic).

jr

hope this is what you mean

Yes, it appears that the Red and Blue wires that go to the terminal strip come from the cap that is mounted in the same clamp as C62 (the cap that the diodes connect to). I can't quite see the end of the cap but there is nothing else in that corner of they must be connected to that cap. Measured to chassis ground, can you measure any DC voltage on the Red and Blue wires?

jr

Measured the red wire to ground and it was 146 DC
Blue wire was 82 DC.

Seems a little low, but at least there is voltage... But you hear NOTHING from the speaker?... no hum, no scratch when you turn the volume control? The Type 41 output tubes should both have DC voltage on pins 2 and 3 (measured to chassis ground)...anything there?

jr

there is crackle ..slightest hum...especially when I put the probes on the wires I hear crackle from the speakers

How about the voltages on the 2 audio output tubes... (The type 41s) These are 6 pin tubes and the pins are numbered with the two larger diameter pins as the "key"... the large pins are #1 & #6. These are the heater pins, and should have about 6.3 VAC between them. Pins 2 are the plates, and should have about 175VDC on them (on both tubes) measured to chassis ground. Pins 3 are G2 and each tube should be around 175 v as well. Pins 4 are the grids of each tube and should be negative voltage. You should hear a louder click in the speaker when you touch pins 2 with the probe, as the tube should amplify the signal.

jr

I replaced all of the caps.
Except the electrolytics that are hooked up screwy to the diodes.
I can now get two local stations (only) with a weak crackly signal.
But that is a milestone..as I got nothing before.
Few weird things though:
Put in the 84 6Z4 with all the pins on it and it works better.
ground pin 4 and the tube lights up..but this does nothing to improve function or signal. so left that out and did not solder a wire to ground there.
On the antenna I hooked it up the way I took it apart and the speaker gets quite.
If I only hook the "G" wire I can get the weak signals..if I hook up the "A" antenna wire..I get no signal...weird huh?.....
So now wondering if I should replace the electrolytics and wire them the way it is with those diodes and resistors on 84 tube.
as the next step?
Look forward to any advices or comment.
Much appreciated.

Just a question about the antenna. There are three wires, right?

John

yeah 3 wires "A", "G", "S".
that how they were labeled with a marker...no signal unless I tought the "G" screw on the radio with a screw driver..or hook up the wire.

What do you think..should I now replace the electrolytics?
Think that could help?

"I replaced all of the caps.
Except the electrolytics that are hooked up screwy to the diodes.
I can now get two local stations (only) with a weak crackly signal.
But that is a milestone..as I got nothing before."

GREAT! REAL PROGRESS! :banana::banana::banana::banana:

"Few weird things though:
Put in the 84 6Z4 with all the pins on it and it works better.
ground pin 4 and the tube lights up..but this does nothing to improve function or signal."

NO! pin 4 is the cathode of the tube... you need to ground pin 1 to connect the heater, it is right next to a ground lug on the terminal strip...about 1/2 inch away from the pin.

"so left that out and did not solder a wire to ground there."

Good for now! It has been suggested that the diodes are more reliable than the tube rectifier... Do you want to keep using the diodes, or cut them out and use the tube?
If you want use the tube, you will need to connect pin 1 to ground to light it up, and pin 4 (cathode) to the electrolytic cap + where the diodes are connected, to put the tube in the circuit. then you can remove the diodes and use the tube. If you want to continue to use the diodes, perhaps ground pin 1 of the tube to light it up but leave pin 4 disconnected.

"So now wondering if I should replace the electrolytics and wire them the way it is with those diodes and resistors on 84 tube. as the next step?"

I would first decide if I want to use the tube or the solid state diodes.

Have fun!
jr

I think Jr tech is right, you need to decide first whether to use the tube or diodes. If the electrolytics were bad you'd either get a lot of hum or they'd probably have killed the diodes. They should get replaced though.

Are you able to tune the stations or do they just come in regardless? I wonder if you might have some bad switch contact.

If the antenna is good you should be able to measure continuity between each wire.

John

Okay..I probably did ground pin 1 for a test and the tube lit up..but it made no difference.

If I have checked the diodes and resistors and the numbers looked okay to Jr.
I would like to just leave that socket alone...and move on.

But I did put in the other tube that did not have one of the pins cut off...that pin went to the #2 pin with a diode..now that the other tube is in that has all 5 pins..it seems to work better.
I can change the stations and only two come in weak and crackly.
The volume works..but not with any great volume.
The trebble/bass also works.
The selector switch that rocks the light selector to different bands seems to have shitty contact..need to get it just right to get a good spot.

Lets please proceed the patient is starting to wake up..we need more anesteshia (wrong spelling)

The voltages that you measured before on the Red and Blue wires of the second electrolytic were a little low... Did these voltages improve when you replaced the other caps in the set?

jr

The red has gone from 146 to now 205
The blue has gone from 82 to now 100
On the tube socket pin3 was 281 it is now 240 and pin1 was 275 and is now also 240.

I checked the (+) cap to chassis ground it was 251 and now is 276
(+) cap to other side (-) was 271 it is now 291.

When I solder pin1 to ground is it to the chassis or somewhere on a terminal strip??
Used cleaner on the control selector..didnt do anything for reception..stayed the same.
Signal only comes in with the A,G,S, three wire antenna..by only hooking up the "G" wire. Put them all on proper screws and no signal..?
Put just "G" back on alone..Touch it with a screw driver it makes loud crack sound and comes in better when I do that.

"The red has gone from 146 to now 205
The blue has gone from 82 to now 100"

Sounds ok if anything the red may be a little high

"On the tube socket pin3 was 281 it is now 240 and pin1 was 275 and is now also 240."

Do you mean pin 3 and pin 2 on the 84/6z4 socket?

"I checked the (+) cap to chassis ground it was 251 and now is 276
(+) cap to other side (-) was 271 it is now 291."

Sounds ok.

"When I solder pin1 to ground is it to the chassis or somewhere on a terminal strip??"

It looks as if the one of the middle pins on the terminal strip (right next to pin 1 on the 84/6z4 is connected to the chassis (Rivet that holds the strip to the chassis), that is where I would connect pin 1.

"Used cleaner on the control selector..didnt do anything for reception..stayed the same."

Oh man, that should have helped !

"Signal only comes in with the A,G,S, three wire antenna..by only hooking up the "G" wire. Put them all on proper screws and no signal..?
Put just "G" back on alone..Touch it with a screw driver it makes loud crack sound and comes in better when I do that."

Do you have a signal generator to use to align the set?
Are the tubes good?

jr

"On the tube socket pin3 was 281 it is now 240 and pin1 was 275 and is now also 240."
Do you mean pin 3 and pin 2 on the 84/6z4 socket?

Yes those are now 240 and pin5 is actually at 6.3 just like you mentioned it could be.
I do not have tube tester or signal generator to do alignment.
I have two rocks that I bang together..it does not help much.
You think my next step is to take the tube to a shop for testing?
They will probably tell me they are all bad..to sell me something.
hope you have some new suggestions..seems like we made some awesome progress so far..but now in limbo...have to put my tin foil hat on an think.

If you have not already done so, you might want to clean all the tube pins. Many times the loctals such as the 7c8,7a6,7b7, XXL will become really corroded. Also it appears that you have two 7b7 tubes ... you might try exchanging the positions of the two 7b7s to see if it makes a difference.

jr

Okay.
I will used some of the solvent cleaner and clean the tube pins and socket assembly.
Also..in my bag of caps I got from Radio Daze..they sent me a .002mf/1600.
I can not find anything in my Philco that this is for.
Also..they ran out of .0047mf/630's..they did not send me them or tell me they could not provide them. Then when I call two weeks ago to replace an order for them..they took the order..never sent me them and when I called back again...they told me they are trying to find some and do not know when they will come in. We are talking almost a month of non commumnication.
Not so good.

Have you replaced Part# 57 on the schematic? ... it is between the plates of the two type 41 output tubes, and is shown as a .002mf.

jr