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

GE M 65 Volume issues
#1

Started on GE M -65( I believe this is identical to RCA 221) and cannot get any volume control. I replaced electrolytics and all other caps.
The pot that was in there I believe is not the right one. According to what I see on the schematic, I need a tapped pot. I cannot find the value of the tap, I have a 250,000 k pot that has a 125,000 k tap. don't know if this is correct. Gave it a try-- medium volume, no control. Found that a 2A7 was in the place of the 2B7, put  2B7 in and volume went down but still no control (AVC here?). Am currently checking resistors and have replaced a few out of spec ones, still working on that angle, the resistor board is next. Also found 2A5 to be very weak, ordered one. Tone control was cleaned and does work.
Any ideas? Last four pages of attachment are for this radio.


Attached Files
.pdf M0014835.pdf Size: 420.24 KB  Downloads: 182
#2

I'd get a new 2A5 in there and do an alignment. You may find that you got a bad IF can or just badly out of tune.
Terry
#3

Any idea what the correct pot should be? 
Thanks
#4

According to this schematic, it does look like a 250K with a loudness tap. Tap isn't super critical.

As far as your volume issue, check to make sure your pot has continuity (250K across the outer terminals), and check R13, 850 ohms, to make sure it's good. I suspect it's gone a ways up in value, and since it looks like a bias resistor for the tube as well as the ground return for the volume control it could be giving you problems.

Also check R10 and R11 (both 1M ohm) as these are in your AVC circuit and almost assuredly have gone up in value. I've seen these go as much as 500% high, or open.
#5

Thanks. These three resistors were first three checked. Both 1 Meg's were way high and the 850 was over a thousand. Had the 1 meg but not the 850- replaced with a 1 K- is that ok?
The pot is checking out Ok. Waiting on the 2A5.
Thanks again. Will get back with results. Plan on looking at if cans after checking resistor board.
#6

No real change with new tube. Wonder if pot is incorrectly wired. How should this be wired? 
Thanks,
Joe
#7

Have replaced all resistors- almost everyone out of spec. Replaced any cracked, brittle wire. Had a little more volume but no control. Still not sure if pot is wired correctly. Any thoughts or ideas would be appreciated. Will recheck everything done so far, even recheck the tubes.
Thanks,
Joe




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 42-345 Restoration/Repair
Hi, there's a lot to consider when designing these circuits so you shouldn't have a lot of concern when replacing caps. ...RodB — 02:03 PM
Philco 42-345 Restoration/Repair
I have ordered and received new caps for this radio and hope I've ordered the correct ones. I tried matching them to the...osanders0311 — 11:35 AM
Philco newbie with P-1891-WA console questions
Hello Jeff , Far as the Electrolytic capacitors go here is a list of parts. that will work . I like using Nichicon and...radiorich — 09:50 PM
Philco newbie with P-1891-WA console questions
Well, I've been stumped at trying to get the first of 11 electrolytic capacitors. I got a schematic and have a list of t...Jeffcon — 07:54 PM
Model 80 Antenna Issue?
Thanks Gary and Rod.  I also found an article in the Philco Repair Bench under Service Hints and Tips, about installi...Hamilton — 12:32 PM
Model 80 Antenna Issue?
Hello Hamilton, here is a little information found in our Philco Radio Library at the bottom of the Home page. Hope it ...GarySP — 11:28 AM
Model 80 Antenna Issue?
I did as you suggested and touching the middle of the volume control did nothing so the coil has to be rewound. Any idea...Hamilton — 10:19 AM
1949 Motorola 5A9M
This would be the second portable in the "other radios" forum where I have a similar one in my collection. I h...Arran — 12:41 AM
Looking for any info: 1977 Ford-Philco Console Hi-Fi Turntable and Radio
Hi PittsburgTost. The record changer looks like a Garrard or BSR (Likely Garrard). The spindles just pull out and pu...MrFixr55 — 11:57 PM
Looking for any info: 1977 Ford-Philco Console Hi-Fi Turntable and Radio
Hello PittsburghToast , Welcome aboard and it looks like gary may have something for you ! now if I dig through my se...radiorich — 11:35 PM

[-]
Who's Online
There are currently 1078 online users. [Complete List]
» 2 Member(s) | 1076 Guest(s)
AvatarAvatar

>