Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Zenith Model K725
#16

I got the kit today with the proper tool. Unfortunately, I can't get the FM aligned as there's no response in trying to do so. I hooked up the generator to the points indicated in the instructions on the 12AU6 tube(grid), put the VTVM on the proper point and hooked the ground to chassis and tried tweaking one of the first IF's and turned it several turns back and fourth but the VTVM didn't respond. The needle didn't move. I had it set on the -DC scale since the tubes grid is negative but nothing. I then tried setting the VTVM to what's called the "zero center indication" buy setting the needle right on the 0 in the +0- setting. Still no response. Any ideas what's wrong? Sort of aggravating when you've waited for the right tool to get here and then no response for FM tuning.
#17

I found out what was wrong. I disconnected all test equipment and tried to get some stations and from low to high end it was totally silent. I had gotten several stations some days before albeit, low volume. Now, there was nothing perceived. I finally decided just to tweak by ear several of the IF's and several stations started coming in and as I tweaked the cans the volume got louder. This FM section must have been way out of alignment so, it's back to the bench and try the alignment again, hopefully this time with some success.
#18

I'm having one heck of a time trying to get the FM stage aligned. I hook up the VTVM to the proper points according to the instructions, set the signal generator or 10.7mHz, tweak the point(s) indicated first and it just doesn't respond. There' very little if any needle movement.

I've tried with and without a 1 meg resistor in series with the VTVM probe to no avail. I know the VTVM is working as it will measure DC as well as AC voltage and ohms so, it has to be something else. All capacitors have been replaced as have most resistors and I've checked the tubes out with an EICO 625 and replaced a couple that were weak or questionable. I don't' know anything else to do. Any suggestions? These are the instructions I followed...

[Image: http://i180.photobucket.com/albums/x220/...161835.jpg]




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
39-7 Magnetic Tuning Vernier Issue...
Howard, First thing you can do is to soak this unit in some lacquer thinner . What happens is the old greese gums up ...radiorich — 01:23 AM
39-7 Magnetic Tuning Vernier Issue...
Hello Howard, I wanted to welcom you to the forum and you have come to the right place to get some help with you Tuning...radiorich — 01:16 AM
39-7 Magnetic Tuning Vernier Issue...
First of all, this is not a restoration.  This radio has been in constant use for as long as anyone in my family can rem...HowardWoodard — 12:14 AM
philco 91 detector transformer
hello i have a bad detector coil and i was wondering dose any one know how many turns and witch lugs aare used and size ...mg34.42 — 11:55 PM
Philco 46-480 Electronic Restoration
I have never hear of the Suppressor Grid to be used in parallel with the Grid. SG sole purpose is to be anti-dynatron g...morzh — 11:03 PM
Philco 46-480 Electronic Restoration
I forgot to make mention of it the other day, but last week I corrected another error on my schematic (applies to both R...jrblasde — 09:27 PM
Gloritone 27 Radio
I have a model 27 that someone painted the cabinet brown. I've been trying to sell it for awhile but the cabinet paint m...Jim Dutridge — 02:30 PM
Restoring Philco 96
Joseph Yeah. The situaction is complicated by me living with my family in NJ while mom is in FL. Were it not for my ...morzh — 10:55 AM
Restoring Philco 96
Best of wishes for your mother. I hope she recovers well. My mother struggles with sciatic pain as well, so I am familia...jrblasde — 10:41 AM
Restoring Philco 96
Well, because I am away, I cannot check it. Hope mom becomes better enough for me to get back. I think I will be here f...morzh — 10:27 AM

[-]
Who's Online
There are currently no members online.

>