[criageek]

Hey jcassity - if you're going to stick with this hobby I think you should get the equipment and learn to do the alignment yourself.  For the couple hundred bucks you're going to pay someone else you could pick up a decent signal generator.  Still...I love the work you're doing!  Just my $0.02!

Rich

[jcassity]

>
Grounding the chassis will eliminate this voltage.

3 prong plug in is the solution then i guess,  i have 35ohms on my utility ground... so my N leg is fine.  My 2011 notes on my panel board say i had no neutral current with my amp clamp either.  the garage where i am working doesnt have any motor loads on right now.  I'll have to redo my power chord and see if that that helps any.

either way when on short wave i still hear a tiny bit of humm,, it reduces in audibility when a chassis gnd is added.

I was actually thinking the band seletor section is rubber isolated somewhat and thought the error was there. THen i looked again and see Philco has a jumper wire from the chassis of the main section to the chasssis of the tuner section so...... i was wrong there.

on my hallicrafers the rubber isolators keep the exterior completly isolated from the radio.

[jcassity]

Hey jcassity - if you're going to stick with this hobby I think you should get the equipment

Rich

yeah but i dont have anyone to teach me how and not make rookie mistakes along the way.

on this radio i count three mistakes that cost me about 3 extra weeks of fooling around when i could have moved forward.

i spent about a month of digging around before joining here.  I had to learn a lot of simple stuff you guys take for granted like the resistor color code differences where the body color was the 1st significant digit, or  "MM" means milli + milli = uF.  there is a huge generational gap on these radios..  I had to learn that what appears to be a resistor is not ,,, its a bumble bee capacitor! 

I learned a lot, not sure how i am going to get the information down to the boys.

[jcassity]

i got a 3 prong power chord installed, im happy with it.

I still have a slight hum on my make shift speaker in the garage.

i turn of all the lights and insure the only thing plugged into any socket is just the radio,, still have a humm,, not bad,, its like a signal hum if thats the right way to put it.  all the hum goes away as soon as i hit a station that tunes in... but comes right back as i roll over into a dead zone.

I live in zip code 24941,, there isnt anything around to cause this issue, we are pretty isolated.

if i recall correctly, this was normal , its been a long while since it was alive.

thoughts on how to cure this?

second question,
i have a bunch of spare tubes and some i have never tested yet because they were given to me many years ago.
is there any possible harm in plugging each in one at a time to verify they operate so i can properly store them for my use later?  can i smoke check any components by plugging in a bad tube?

~~i checked the temp on my R102 issue  , the one getting hot my temp sensor cant find a value greater then 200degF,, is this ok?

my next task is to hide the pieces parts that enable satalite radio or internet based stations. gotta figure this out.

[jcassity]

powered up each spare tube one at a time and found one bad.

as to the humm, i was wrong,, the hum does not go away when i am on a station, its still there... its just low enough to sorta wash into the stations reception so to speak.

Moved wires around a little with a non-conductive tool to listen to an audible differece and there was none.
placed a metalic shield over the 7AF7 , no benifit other than it seemed stations came in a tad better.
sank a 10' copper clad gnd rod and sourced the radio ground here, did not take humm away


i have a couple tubes that i will never use, if anyone wants them.

not sure what to do about the slight hum i have on shortwave only,,

troubleshooting repairman guide says that a hum will occure if the C209 is open,, i had 19vdc on one side and 0v on the other so its certianly not open,,, C209 is grounded on one side.

[morzh]

I do not see the C209 (or anything with this order of referencing) here
http://www.nostalgiaair.org/pagesbymodel...013588.pdf

C35A/B could potentially cause hum.
Also, powering through a cheater plug might tell you if grounding affects it.

[jcassity]

see section 2 , very far bottom left.. C209 bonded to chassis

nostalgia air does not have a code 125,, they do have a code 121 available. code 125 is a make up of code 122 and all of its updates.
to be nice,, i updated post 1 with all this information so the reader has the info on the front end.

this diagram coupled with the code 122 run updates and code 125 updates= a code 125.
there is no known schematic dedicated unto a code 125 stand alone

also i used a three prong to 2 prong adaptor to gain controll over my third prong, thats how i was able to reference ground to a new source.  The third prong adaptor had an eyelet available ,, the kind you utilize the outlet face plate screw to gain the third conductor.

[jcassity]

i just solved my Hum i had.

i started tinkering with all the IF transformer caps and noticed something.
each one of them was almost if not all the way bottomed out.
i was wondering why i was not hearing any real good usable sound until i rotate my vol knob about half way up.

I tuned to a station that came in really clear and then one IF at a time i payed attention to what my fine adjustment did to the signal then put it back where it was.  I moved on to the next one and repeated.  Then the final IF transformer i did the same.

I simply backed out the adjustment and payed attention to other stations and particularly wwv.

seems i have a ton of volume and i am getting more stations than before with the volume knob at a lower setting.

I have no idea what i just did but it sounds like progress for another piece of this project.

As a kid i remember the radio coming back home after being fixed and dad saying,, "this radio isnt playing right, that guy didnt do a good job". sometime soon after the radio broke and it sat as a decoration in the house till mom one day said to get it out of here. it went out into a little storage shed without any real climate control and that was i think around 1980.  Who ever that was,, perhaps he was setting up for a alignment but forgot to finish it.

all the caps on the IF's were basically bottomed out. 

once i fiddled around with the three of them backing off some,, like all in probably i have them backed off a half turn or so,, things are much better.,, well more like the difference of night and day.

[jcassity]

part 2 of today.

prior to my discovering how to fix the volume issue,  i thought that since my R102 that was getting really hot, i retofitted in a multi-tap resistor in my pic.  end to end its 611 ohms.
i relocated one of the wires to give me 400 ohms in an effort to see if this got rid of the hum and my minor lack of high high volume.

I am so lucky i stayed with the radio for a while when i connected to the 400 ohm side, i was tinkering around and wow!!, my transformer was getting very very unusually hot!!   Laser temp gun said it was 168 deg F. 

my goal was to introduce 400 ohms to see if this would fix my volume problem and maybe my hum.
this did nothing for the hum or volume.  It resulted in my 6k6 pin 3 sitting on 305volts and pin 4 getting to around 260v.

when i found the transformer was getting too hot i reverted back to 611 ohms side of my R102.

It occured to me that i have an opportunity to let heat out of the transformer easily because one side comes off whithout any wiring conflicts.

i removed the one side cover of the power transformer.
i drilled a hole on each side down low.
the purpose i feel for these two holes is to allow the heat convection to suck air in,, then the opening at the top acts as a chimney.
I hacksawed a slot along the top and sorta bent it out a tad so nothing can drop into the transformer giving it an awning so to speak.

now when there is a heat issue, a lot of it can get out instead of being trapped and such.

now i cant find any spot on the transformer that is over 115 deg f.

the vast majority of the heat introduced on the power transformer is sourced from radiant heat off the rectifier tube and the 6k6's on the other side you cant see.
what i do know is that 300 ohms is wrong for the code 125 update.. 500 ohms is ok,, and 600 or so is working for me. just my 2c worth but its been a good trial and error on the part of an amature here who knows little about these sets , but thanks to the help here, im getting more comfortable.

[jcassity]

now on to sourcing my dial glass.
since i have a pointer thats broken up at the slider part, RadiolaGuy said to just fab up a pointer and attach it to my slider then paint it up and be done.
seems like a reasonable fix to me. I should be able to do this with little delay.

putting the radio back together and in the chassis will be my last step, should have the needle built tomorrow.

glass wont be in my hands for 2 weeks, since they are custom made to order for around 25$ or so.

[jcassity]

my first go at making a pointer needle.  Had to make it two parts if i wanted it fast and i was surprised this only took an hour to fab up,, not counting paint. had to stare and compare at various images and such to get the shape fairly close. I think i have my colors wrong though,, i think OEM was white on red,, not red on white.
also i was able to shave off an addtional 20degF off of R102 by adding that pigtail copper roll heat sync you see there that stands out like a green fly in a sugar bowl.
so far so good.  just waiting on the dial glass and im all set,, umm,, well until idecide to work on the turn table part.

[jcassity]

on the upper right control knob that switches from Broadcast to SW to Phono, the linkage is in error by design.
it can only be installed two ways.
one way works until you go to sw
one way works for both shortwave and Broadcast however when you switch to PHONO, the linkage presses up directly against the dial string.
to fix grind away the metal that gets in the way to clear out the phono position.

[jcassity]

I did some reading and found an old patent on heat sync slip on metal corrigated tubes that slip over a hot tube to help wick heat.  That gave me the go ahead to rig something up on my own.


I studied where the vast majority of heat production was and found that its the hottest right at about 90% up the tube.  of course this makes sense so i designed a heat sync for my rectifier and dual 6k6's.

I used metal strap material and made it into a hook which comes around and bolts to the aluminum plate.  think candy cane hook.  It friction slips on and can expand and contract without worry of breaking the glass.

another thing is that when installed, the chassis sits at a 45deg angle,, well close enough for the sake of conversation,, and the orientation of the recitifier tubes and the two 6k6's , these tubes just radiated a ton of heat upon the transformer. prior to this mod with the radio on the work bench simulating the angle, i recorded 138degF on the transformer. Now i am hard pressed under the same simulation to find over 100 degrees.

i was able to shave off about 40deg on each tube doing this. 

funny, now that one 6k6 that had a lot of blue dancing around ,, well you can barely notice any blue at all.

i have since added another hunk of aluminum to gather even more heat but this has to be enough.

[jcassity]

got my glass today from Radiodaze.... awsome!

for some reason i believe i recall the back of the glass being a gold ish color meaning that you only saw the pointer needle trhrough the oval like dial slots, i dont recall being able to see the whole needle on the old glass.

this is good enough ,, and its worth the purchase

[jcassity]

back in service,, now to figure out a random outside antenna wire now that its in the house.