[murf]

Hi Philco fans,
Have a Philco lowboy model 90(later version)
Has the 9 tube chassis that does not have the twin 45 tubes.
Looks like a 47 and 27 instead.
Tube lineup is 3  24 tubes, 4  27 tubes, a 47 and an 80 tube.
Looked on NA and they only have info on the earlier version.
Looks like there is a couple 800 volt caps under there. Is that what it came with from the factorey?
Do they need to be replaced with the same?
Thanks,
murf

[Ron Ramirez]

Look again:
http://www.nostalgiaair.org/Resources/881/M0013881.htm

Scroll down the several pages...they do have the schematic for the 1-47 version of the 90 in there.

Or if you get bored, you can always look here:
http://www.philcoradio.com/tech/images/90b.jpg

You can use 600 or 630 volt caps to replace the caps inside the bakelite block shells; 450V is fine for the electrolytics.

[murf]

Thanks Ron

[murf]

Have a couple questions.
Eyeballing this chassis, and have found a mica cap that was apparently added at some point.
It is connected to bakelite block #52 on the parts list(farthest terminal from screw) and to ground.
It was broken in half and taped together with elect. tape.
Leads were loosely attached.
Don't know what value it is, or if it is needed.
Don't see it on the schematics.
Also noticed electrolitics 56 and 57 have 6 and 10's in the copper housings.
Looks like 1 terminal on the bottom of the can on each.
How are these 2 caps wired from the bottom? Not real familiar with these old Philco's.
Schematics don't show both 6 & 10 caps wired seperately.
[Image: http://i1161.photobucket.com/albums/q509..._mica2.jpg]

[Image: http://i1161.photobucket.com/albums/q509..._mica1.jpg]
I am probably just reading them wrong.
I assume I can use 10mfd x 450 volt for all 4 of these?
Will send a pic of the mica cap in question.
murf

[KCMike]

Murf, you might check any changes that might have been made to that model.
When recapping a philco 16b I found a mica cap coming off one of the tube pins that wasn't on schematic. It was noted in the changes info. and explained why it was added.

[Steve Davis]

Remove the mica capacitor. Replace the two capacitors inside of item 52 with .015 or .010 safety caps. The filter capacitors 56 and 57 should only have one capacitor in each can, 10 uf would be fine.

Steve

[murf]

Thanks guy's.
I imagine Mark Oppat would have the safety caps.
I need to place an order for more caps anyway.
murf

[morzh]

I bought like 100pcs, in Mouser.

These

http://www.mouser.com/ProductDetail/Vish...r%2f1SM%3d

[murf]

Well, Did some checking tonite and it looks like a couple 10uf electrolitics were added under the chassis, but they never disconnected the old caps in the cans. All wires are still tied to the lugs and the cans show no signs of being opened.
Caps were added downstream.
Have never seen this before.
Just to verify, I removed the tabs from the lugs with all wires still attached and powered it up.
Powered up fine, so I checked a few tubes for voltages.
The 24's are supposed to have 250v. Two of the were around 240v and the 3rd one was only checking about 5 volts.
Apparently something is choking off the power to that 24 tube.
Have no sound other than some crackling and a slight hum coming from the speaker.
If I tune across the dial with another radio playing, I can get some interference type noise from the other radio at a certain frequency.
ANy suggestions from the Philco experts?
murf

[morzh]

You have an open coil, most likely.

[Steve Davis]

Check the primary (the outer winding) of item 6 on the schematic for continuity.

Steve

[murf]

Well guy's, I checked the coil tonite, and here is what I found.
Have 235 volts coming into the coil. (#7 on the schematic)
Ohmed it out between that lead and the lead going up to the #24-RF tube. Checked open.
Guess I should pull that coil and send it to Ron for re-winding.
Also found that someone had replaced the tone switch and hacked the 2 leads up.
I want to re-wire that, but I can't decipher the schematics on the end points of both of those leads.
One was cut long and wrapped up with one of the leads from the switch which is also quite long.
I am wondering if the 2 leads wrapped together are supposed to connect to something else? There is no tape on the ends of the wires.
Or, did they just leave them both long and wrap tape on the ends because they were lazy?
Could someone tell me how to wire the tone control switch?
This thing has been repaired by a hack for sure.
I can send a pic of the wires in question if needed.
murf

[morzh]

Murf

The tone control switch has to be rebuilt as it has capacitors (part 31) that have to be replaced.

The slider is grounded, so the capacitors (in order that they are, the values are here)
http://philcoradio.com/tech/images/90b.jpg
are connected to the common wire that goes to the plate of the 47 tube, and the other end of each is wired to the contacts of the switch to which the slider connects in each position.

So you only should have one wire coming out of the regulator. (the other is GND)

Bite off the old wires, pull the potted part out (it is wrapped in fish paper), separate and discard the caps and save the paper.
Then put the paper back, place your caps inside, connect them together on one side and solder to the case, route the other wires (use thin insulated wire soldered to caps' leads), solder to contacts, pot with hot glue.

This is it.

I showed it in my 90 restoration.
connect your caps with

[morzh]

http://philcoradio.com/phorum/showthread...light=tone

This is a 90 tone control restoration by myself.

[morzh]

Murf

I ain't sure no more but the component you are showing looks an awful lot like a volume regulator potentiometer, not the tone switch.

Now if it is the case (it is part # 20) you have one end grounded, the middle one goes to 27 tube DET AMP's grid, and the third pin (you are holding the wire from it) goes to where caps 18 and 19 connect together.