1. The PHILCO Phorum
  2. Various and Sundry Categories
  3. Test Equipment
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Threaded Mode
RCA WV-98c
morzh
Odobenus rosmarus
*****
Posts: 15,797
Threads: 553
Joined: Oct 2011
City: Jackson, NJ
#31

11-10-2024, 09:22 PM
strange. It should have more even to the GND, and the GND is 1M to the case.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Find
daveone23
Member
***
Posts: 95
Threads: 19
Joined: Jun 2024
City: tampa State, Province, Country: florida
#32

11-11-2024, 08:30 AM
Are you saying if I measure ohms from the ground lead to case it should be 1m ohms? That low resistance tells me there is a leak to ground, right?
(This post was last modified: 11-11-2024, 09:03 AM by daveone23.)
Find
morzh
Odobenus rosmarus
*****
Posts: 15,797
Threads: 553
Joined: Oct 2011
City: Jackson, NJ
#33

11-11-2024, 08:47 AM
Well, in the sch you provided (there is something missing at the very bottom, but I think it is GND), the sole connection to the case shown is the 1M resistor R31, which is used to bring the case and the GND under the same potential.
Unless I am missing something.

Of course there is a cap across that R31. And it could be bad. Or, again, we are missing something.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Find
daveone23
Member
***
Posts: 95
Threads: 19
Joined: Jun 2024
City: tampa State, Province, Country: florida
#34

11-11-2024, 09:17 AM
I guess I need to look at r31 and C7.


Attached Files Image(s)
   
Find
morzh
Odobenus rosmarus
*****
Posts: 15,797
Threads: 553
Joined: Oct 2011
City: Jackson, NJ
#35

11-11-2024, 09:25 AM
That too.
There might be other things.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Find
daveone23
Member
***
Posts: 95
Threads: 19
Joined: Jun 2024
City: tampa State, Province, Country: florida
#36

11-11-2024, 04:28 PM
Interesting readings, r31 common ground to case bounced to 1meg on analog meter, r31 common to case bounced to 1meg. R31=1meg.  Across c7, which is common to case with a parallel resistor = 40k ohms steady.
(This post was last modified: 11-13-2024, 11:41 AM by daveone23.)
Find
daveone23
Member
***
Posts: 95
Threads: 19
Joined: Jun 2024
City: tampa State, Province, Country: florida
#37

11-11-2024, 06:40 PM
My resistance readings are not even close. Worried about pins 1 and 6. Even though they are off, the meter works on dc 50v and higher.
(This post was last modified: 11-13-2024, 11:41 AM by daveone23.)
Find
morzh
Odobenus rosmarus
*****
Posts: 15,797
Threads: 553
Joined: Oct 2011
City: Jackson, NJ
#38

11-11-2024, 07:20 PM
>>r31 common ground to case bounced to 1meg on analog meter, r31 common to case bounced to 1meg.

Would you re-read and correct?
This does not make sense.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Find
morzh
Odobenus rosmarus
*****
Posts: 15,797
Threads: 553
Joined: Oct 2011
City: Jackson, NJ
#39

11-11-2024, 07:21 PM
Check all your caps. Even ceramics. I am not sure what is going on.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Find
morzh
Odobenus rosmarus
*****
Posts: 15,797
Threads: 553
Joined: Oct 2011
City: Jackson, NJ
#40

11-13-2024, 10:24 PM
Just occurred to me: what if you have a power transformer leak? From a, say, secondary to the case. If it is bolted to teh case.
Not sure how to better check it.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Find
daveone23
Member
***
Posts: 95
Threads: 19
Joined: Jun 2024
City: tampa State, Province, Country: florida
#41

11-14-2024, 09:46 AM
Thats a good thought but the secondary does go to ground via R30 27k resistor.
Find
morzh
Odobenus rosmarus
*****
Posts: 15,797
Threads: 553
Joined: Oct 2011
City: Jackson, NJ
#42

11-14-2024, 10:26 AM
Yes.....it would connect GND to case, and you do have 1MOhm.....

I am not sure how the wiper has resistance to the case.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
(This post was last modified: 11-14-2024, 10:29 AM by morzh.)
Find
daveone23
Member
***
Posts: 95
Threads: 19
Joined: Jun 2024
City: tampa State, Province, Country: florida
#43

11-15-2024, 03:56 PM
From now on iam using an analog meter. R31 removed is 1 meg and c7 .01 but chassis to common is 600k. Why is that?
Find
morzh
Odobenus rosmarus
*****
Posts: 15,797
Threads: 553
Joined: Oct 2011
City: Jackson, NJ
#44

11-15-2024, 04:22 PM
Are you saying the Chassis to GND became LESS when you removed the R31?
And we are sure the C7 and other caps are not leaking?
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Find
daveone23
Member
***
Posts: 95
Threads: 19
Joined: Jun 2024
City: tampa State, Province, Country: florida
#45

11-15-2024, 05:57 PM
Yep, hunting down the source. Will get back to you. Thanks
Find
« Next Oldest | Next Newest »




Users browsing this thread: 6 Guest(s)
[-]
Recent Posts
IF can wire size and Rubber mounts?
Hello PHORUM members, I am still working on restoration of my PHILCO 37-640.  I want to start with rewiring the IF ca...georgetownjohn — 06:32 PM
Gilfillan Brothers Car Radio?
There is a Mission Bell model 19/19A that could be what you’re looking for, Riders vol 4. It has the tube line-up of: 0Z...Joe Rossi — 05:01 PM
Looking for verification of correct schematic.
Definitely 870044RossH — 01:12 PM
12' Philco
Wonder if the chassis was big too.daveone23 — 12:38 PM
Philco 38-2 Automatic Tuning
Hi Ron, I have sent Radio Daze my concerns with the dial so I guess we will see. They used my original to make the repro...dconant — 12:27 PM
Hickok AC51 tube tester
How does the  5W4 and 83 tube filaments get fed?martinj — 12:25 PM
462ron
Hi Dan, your original dial appears to be lighter, easier to allow light through. My original is similar except it’s crac...462ron — 12:07 PM
Philco 38-2 Automatic Tuning
I received my new 38-2 dial. I'm a little disappointed. As you can see in the picture the blues have a white shadow. The...dconant — 11:13 AM
Philco 38-2 Low Volume
I have been playing my 38-2 for a while now and it is doing very well. I did have to replace the 6A8 (osc) as it develop...dconant — 11:03 AM
Philco Speaker Spider
Hello, Does anyone with a 3 D printer make the spiders for those old Philco speakers? That might be a good idea for some...dconant — 09:41 AM

[-]
Who's Online
There are currently 3562 online users. [Complete List]
» 2 Member(s) | 3560 Guest(s)
AvatarAvatar

>
  1. The PHILCO Phorum
  2. Various and Sundry Categories
  3. Test Equipment