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
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
Restoring Philco 96
Nice find! I hope it completes your console.jrblasde — 08:45 AM
Gloritone 27 Radio
Hello john, That, is the first time I have have seen or heard of that brand and model. Welcome to the party !! Sincer...radiorich — 08:08 AM
370 Norman Bel Geddes trim pieces
Thank you! I’ll probably use the half-round molding and tone it to match the original. Thanks for the replies!Max T — 06:34 AM
Gloritone 27 Radio
I'm kind of late to this thread, but Buzz1151 has a 3 part restore series on the model 27: A little bit of extra t...Eliot Ness — 05:48 AM
370 Norman Bel Geddes trim pieces
You can get half-round moulding in various diameters at any home improvement store. That way the flat edge is uniform. ...GarySP — 12:03 AM

[-]
Who's Online
There are currently 1693 online users. [Complete List]
» 1 Member(s) | 1692 Guest(s)
Avatar

>