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

RCA 85T ??
#1

I have an RCA 85T, I'v recapped all the paper Caps, I used 10 Mfd Electrol. for C 18 C19 and C20 (was 8, 5, and 5) No static but when I tune 89 and higher on the dial the volume drops considerabilly. All stations track there place on the dial. do i have an A.V.C. problem ? or something else ? can any one steer me in the correct direction ?
b.t.w. I replaced the power Transformer, it was leaking wax.
Thank you for any and all help !
Jack
#2

Check your alignment instructions and see if there is an adjustment for the high-end of the band.
#3

Looking at the schematic, looks like this would be C1.
#4

Also check your 6A7 tube. I've seen too many recently with the weak pentode section, and in this radio where it is both mix/osc and 1st RF it may be critical.
The tube should be at least 800 (the chart gives 1000) on the pentode and above 150 on the osc.
#5

Thanks TA, morzh's
I touched up the Alignment(C1, C5) it helped somewhat.
I will get another 6A7 to try.
Thanks again Both of you

Jack
#6

Jack

Make sure you DO know your 6A7 is good.
I had weird experience with them just a month ago (I needed to check the theory that my 6A7 was not oscillating properly below 6MHz, my FB band did not work there at all) where I bought an NOS tube from a guy (and he was an honest guy) and it tested about 600 instead of 1000, which is "?" territory. I was able to prove the theory (the oscillator worked as it should) but the tube was weak. That was #1.
Then I bought another NOS tube from another guy and it was near-dead, at 300. The guy admitted he did not test the tube as his tester does not test them, and sent me another RCA NOS one and that one was just fine (that's the one I keep in the radio). That was #2.
But before this guy had a chance to react I bought the third tube, also NOS and this time the guy claimed he tested it and it was like 150% or so (not sure what that means).
The tube came, and again, the pentode section was extremely weak. I suspect he tested only the oscillation section (in all three tubes it was indeed very strong).

So, out of four tubes and from three sellers only one was testing properly.
So make sure you buy from someone who tested it on a mutual conductance tester that tests both parts, the oscillator and the pentode, and both are close to new value or at least show strong "good". Ask the seller about how he tested them.
Or go to one of the sources folks here recommend (Bob Dobush at findatube.com).




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
The list of my radio & TV collection!
A little light Saturday positive about our hobby in our feed... My new every Saturday video about antique radio equipme...RadioSvit — 02:12 PM
Model 70 Cabinet Trim
musar , Well if you have any more questions feel free to post away . Sincerely Richardradiorich — 08:56 PM
Model 70 Cabinet Trim
Although I have not made any cabinets or cabinet parts for a couple of years, I still have some parts left over, includi...Steve Davis — 06:26 PM
philcorepairbench.com - shadow-meter
Thanks Ron. But I can't find those articles.fenbach — 02:43 PM
Model 70 Cabinet Trim
Thank you, Gary. Before making my original post, I had clicked on "Steve Davis Cabinets" only to find that it...musar — 02:25 PM
philco predicta
Welcome to the Phorum, cgl18! I am not your resource for television repair, but lots of friendly help is available here...GarySP — 02:12 PM
Model 70 Cabinet Trim
Welcome to the Phorum, musar! You can send Steve Davis a private message (PM). The site is at the top of the Home page...GarySP — 02:09 PM
Model 70 Cabinet Trim
How do I contact him? The only contact information for him I could find when searching online was a telephone number th...musar — 10:38 AM
philco predicta
Hello, good afternoon, I would like to ask what the possible problem could be if I don't have an image on the screen. I ...cgl18 — 10:19 AM
Philco model 38 code 121 not receiving signal.
So one last question before I finish this radio. Regarding the speaker and output transformer. I salvaged the original o...Stormlord5500 — 09:31 AM

[-]
Who's Online
There are currently 1170 online users. [Complete List]
» 1 Member(s) | 1169 Guest(s)
Avatar

>