Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Antique Radio

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #1  
Old 07-22-2017, 01:42 PM
Schanz's Avatar
Schanz Schanz is offline
Pioneer Stereo Fan Club
 
Join Date: Jun 2014
Posts: 94
Another Philco 87 question

Brought it to life today but I need to solve an issue with the volume. Seems to be a bad connection like it just needs a cleaning. However, when I do get volume it's just loud, there's no variance. I took the control out and began cleaning the band with deoxit. It is covered in a very thick layer of black. Almost like it was coated on purpose. Should the band be cleaned to bare metal?

Sent from my SAMSUNG-SM-G920A using Tapatalk
__________________
Looking for a dial glass and knobs for a R-30s Fisher console.
Reply With Quote
  #2  
Old 07-22-2017, 02:22 PM
Schanz's Avatar
Schanz Schanz is offline
Pioneer Stereo Fan Club
 
Join Date: Jun 2014
Posts: 94
Ok, so I took the band out and it appears to be some type of carbon. I reassembled and tested and I get zero to 20k ohms.

Sent from my SAMSUNG-SM-G920A using Tapatalk
__________________
Looking for a dial glass and knobs for a R-30s Fisher console.
Reply With Quote
  #3  
Old 07-22-2017, 02:51 PM
Electronic M's Avatar
Electronic M Electronic M is offline
M is for Memory
 
Join Date: Jan 2011
Location: Pewaukee/Delafield Wi
Posts: 14,758
Carbon resistance element pots SHOULD be coated in carbon, don't remove it or the pot will go open/be ruined.
__________________
Tom C.

Zenith: The quality stays in EVEN after the name falls off!
What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
Reply With Quote
  #4  
Old 07-22-2017, 06:47 PM
Winky Dink's Avatar
Winky Dink Winky Dink is offline
VideoKarma Member
 
Join Date: Apr 2010
Location: Meridian, Idaho.
Posts: 583
I think the volume control pot is part no. 3076, which is 10K ohms. If you're at 20K and want to reduce the resistance, you can sprinkle powered graphite on the carbon element and burnish it with a smooth instrument. If the resulting resistance is too low, just lightly wipe off some of the graphite with cotton. Keep adjusting that way until the resistance and taper are satisfactory.
__________________
Winky Dink
Damn the patina,
Full speed ahead!
Reply With Quote
  #5  
Old 07-22-2017, 09:07 PM
Findm-Keepm's Avatar
Findm-Keepm Findm-Keepm is offline
Followin' the Rules...
 
Join Date: Jun 2007
Posts: 2,832
I have the Model 86 with a very similar chassis - my volume pot measures almost 18k out of circuit, and I can control the volume okay. One thing about my Philco, and yours as well - the volume pot is more of an RF gain - with my hand on the knob, I can couple enough RF that it raises the volume, and when I remove my hand, it lowers by 50-75%. So I set it "loud" and remove my hand for a more pleasing volume.

My radio has been in the family since the early 70s. Dad got it from a customer that "needed room" - one 27 tube later, and she played fine. Original cap blocks and filters, no alignment what so ever, and I can tune the AM dial, strong stations only, with no antenna - I get 7 stations out of 11, so I'm leaving it alone.

One thing I do need for my 86 "lowboy" is a pattern for the grille - everyone with one that's intact has declined to trace it for me. One of these days someone will offer up a PDF or a stencil on eBay - another way folks can make money off scarce Philco stuff. It's a back burner project for me...
__________________
Brian
USN RET (Avionics / Cal)
CET- Consumer Repair and Avionics ('88)
"Capacitor Cosmetologist since '79"

When fuses go to work, they quit!
Reply With Quote
Audiokarma
  #6  
Old 07-22-2017, 10:36 PM
Schanz's Avatar
Schanz Schanz is offline
Pioneer Stereo Fan Club
 
Join Date: Jun 2014
Posts: 94
After putting it back in, the volume adjusts nicely but the volume is very low and inaudible if I take my finger off the shaft. It is nighttime though. I'll try again in the daylight but I may need to try the graphite as well go through all the components again.

Sent from my SAMSUNG-SM-G920A using Tapatalk
__________________
Looking for a dial glass and knobs for a R-30s Fisher console.
Reply With Quote
  #7  
Old 07-22-2017, 11:37 PM
Findm-Keepm's Avatar
Findm-Keepm Findm-Keepm is offline
Followin' the Rules...
 
Join Date: Jun 2007
Posts: 2,832
Do you have a longwire antenna connected? Remember, the volume control is in the RF stage, and you've gotta give it some signal to work with.

I'm somewhat urban, with 10 of the 11 AM stations within 30 miles of me. With a longwire antenna, I get only two - the strongest two, bleeding over the others. At night, it's better.

If you are rural or more than 30-50 miles away, you'll want a longwire antenna. Mine is simply magnet wire suspended in my attic, about 25 feet in length. Ground is via a grounding rod outside, also unsure of length, as it was here when I bought the house in '90...
__________________
Brian
USN RET (Avionics / Cal)
CET- Consumer Repair and Avionics ('88)
"Capacitor Cosmetologist since '79"

When fuses go to work, they quit!

Last edited by Findm-Keepm; 09-29-2017 at 06:39 PM.
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 03:21 AM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
©Copyright 2012 VideoKarma.org, All rights reserved.