Why no love for this GE roundie ? - Page 14 - Videokarma.org TV - Video

tvcollector · #**196** 01-08-2015, 05:27 PM

I mounted the new terminal, reconnected everything, and it's still doing the same thing.. BTW the hum turns up/down with the volume control, all the way down you don't hear it.. I don't know what else to think of.. Either there is a problem with the first can, or I could have accidentally disconnected something else by moving the chassis around.. Or blew something up even though I didn't ever hear anything or smell anything.. I don't know where to go from here, other than give the set to Dave to look over.. I even checked for possible wires for continuity, ground continuity from terminal etc.. And everything looks fine.. I can't check the big green power resistors on the power board seeing how Sams only lists specs for only a few of them, and don't know the values..

Here's a pic of the crystal that glows when HV comes up..

Electronic M · #**197** 01-08-2015, 06:57 PM

N701 appears to be a neon bulb...They are supposed to glow orange. They were often used like zezer diodes are now. A gas regulator diode tube (0Z4 for instance) is basically a fancy version of that.

tvcollector · #**198** 01-08-2015, 07:41 PM

So I guess the problem is only speaker hum.. I did power set up again, and did some tests the B+ voltages are normal.. The picture is the same as it was... I did remove the audio output tube and the hum went away.. Seeing how the audio TS is on the very front edge, and I did set the chassis on it numerous of times, the problem maybe that... I did look at it and I don't notice any issues by eye.. The old can, the last one I replaced seem to have some bad values in it, one value, my ohm meter could not get a reading out of.. It sat there trying... Perhaps maybe I replaced with good caps now causing an issue somewhere else that perhaps was adjusted to bad caps? Perhaps maybe try to adjust any sound coils? When I power set up, I notice a slightly louder transformer hum than I normally heard, and I don't think it's coming from the power transformer, it's coming from the audio transformer..

DaveWM · #**199** 01-08-2015, 07:48 PM

what was the orig problem?

tvcollector · #**200** 01-08-2015, 08:02 PM

I don't know what an original problem would be.. But now it's speaker hum..

Electronic M · #**201** 01-08-2015, 08:28 PM

He means what was the matter with it before you caused the hum.

Here is a good way to isolate the hum: unplug one and only one at a time the audio tubes before the output and see which stop the hum and which don't. For instance if the one before it stops the hum then that stage is not at fault, but if it does not then look for a problem in the components between it and the output.

Don't tweak the adjustable coils unless you can confirm via proper troubleshooting that they are at fault if you walk them too far away from correct when they are not the trouble you will only give your self needless headaches down the road.

tvcollector · #**202** 01-08-2015, 08:47 PM

There was no other issue before I caused the hum, other than things not related to that..

I unplugged one at a time 6EH7 one and two, and then 6EJ7 that are located near the Audio Transformer still a hum in between..

Unplugged the 6M11, still a hum.. Then I unplugged the audio output tube, again and no hum.. I tested that audio output 6AL11 tube just now again, and the short light comes on, on my tester.. Hmmm... Not sure if a shorted tube would cause that, and it be all of a sudden...

DaveWM · #**203** 01-08-2015, 08:59 PM

HK shorts can cause hum in audio tubes.

tvcollector · #**204** 01-08-2015, 09:10 PM

Well, I guess I'll be making a tube order again.. If that is the case than I guess there was never an issue with my restuff job...

DaveWM · #**205** 01-08-2015, 09:19 PM

does not always but "may" cause a hum. is it a hum or a buzz?

tvcollector · #**206** 01-08-2015, 09:45 PM

It's more of a low pitch transformer hum sound coming out of the speaker.. Some people may call it a buzz noise.. I've been running the set for an hour now and it has seem to be gone or at least very minimal.. looks like it may be a drift issue..

zeno · #**207** 01-09-2015, 08:11 AM

6AL11 is 1/2 audio out & 1/2 audio detector.
http://tubedata.milbert.com/sheets/127/6/6AL11.pdf

Bad part is most likely the detector if its a buzz.
Also if the out section were bad the hum wouldnt go away
with the VC turned down. As a rule hum= output
buzz=detector hiss=sound IF.

If its not the tube watch for open coils, the set must be getting
brittle & moving things can do it.
DO NOT tweak the coils !!!!

73 Zeno

DaveWM · #**208** 01-09-2015, 08:18 AM

what zeno said about the coils. watch out for those flat coils all over the place very fragile and easy to break.

tvcollector · #**209** 01-09-2015, 01:07 PM

Believe it or not the noise went away on it's own.. I let it run for a few hours last night, then a cold power up just now, and still no buzz.. I think with the volume control all the way up, I can hear a hum noise ever so slightly.. But that's odd how it goes away on it's own...

tvcollector · #**210** 01-12-2015, 08:26 PM

Well I went to replace some more orange drop caps.. Forgot to resolder one of the resistor leads that I mistakenly unsoldered thinking it was the cap.. And the anode wire broke off.. I resolder that to where it broke off, at the solder terminal next to where the shunt tube wire cap connects to.. Powered the set up, and the HV output tube started to get super bright.. I then resoldered the resistor lead, powered up again, HV output tube lights normal, but HV does not come up now at all.. And I just tested the 6JS6 and it's real weak now.. I don't have any other tubes that are 6JS6 and the RCA models have a different tube number.. Not sure if one from a CTC15 or 16 would work as a substitute to at least power up..