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Hallicrafters S53-A
#46
i just reached out to hallicrafters expert Chuck Dachis , i totally forgot he was the one who confirmed with me my conclusion that the another radio of mine (S38-d) had an error on the schematic.

today i am focusing back on the IF T10. I have 100pf caps installed. as a result to achieve max volume the slugs need to be bottomed out.
This must mean the IF does not have enough capacitance accoring to Terry which is a great god like epic super hero here to me.

we considered some options to solve the low volume issue now that i was forced to omit my oem silver mica cap.

the radio is trying to tell us to increase the capacitance in order to be able to back out the slugs some.

I installed 150pf on each side of the IF and the volume went up some.
i installed 200pf and with the vol knobe at max, the sound from a local station feels like the knob is at 60%.

if i open the tuning caps and inject the freq gen, the noice coming out of the speaker is unbearable with the vol knob at max.

Maybe Chuck will help my cypher this more as well.
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#47
When performing an IF alignment, it is important to keep the signal as low as possible so you just hear the audio out of the speaker. With a ac voltmeter across the speaker with volume at max you start with T12 secondary and peak it, then go to the primary and peak it. If the volume jumps up, turn the signal down again. This is critical as the AVC circuit cuts in with too much signal and you will never find the peak.

If you keep tuning the transformers without any success, they could all be so far out that you may have to start by injecting the signal at the grid of each stage and peak one transformer at a time.

For example:

With a small cap, .01 or so in line with your signal generator, inject the IF frequency into the grid of the 2nd IF tube, (pin 1), and peak T12 again with low signal. Repeat the process at the 1st IF tube grid, and the go to the mixer grid last. All the while you should have to keep reducing the signal as I mentioned earlier. If each stage peaked, you can now keep the signal at the mixer grid and then re-peak every thing again starting at T12.

If along the way you find a transformer that won't peak, then it is likely bad, or the tube is not amplifying. Each stage while working backwards to the mixer should have gain requiring you to lower the signal. It is not impossible to have more than one bad stage, and this will help you find it.

I forgot to mention that the sig gen should be modulated with 400 Hz audio during this test.

Hope this helps.
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#48
tbone
thanks, that first set of suggestions taught me something.
I have been peaking the IF's in order by the way. Any time i made a change i would start over at S1 and migrate over to s6. i was not jumping in at random.


i have two ceramic caps listed as ".22" in my spare parts.
when caps are stamped with a Decimal point before the numbers, arent these supposed to be default Nano Farads?

since i have 200pf installed now on T10, and i have noticed it wants more capacitance, i could r&r the caps and insert these two .22nf caps which would be 220pf......
this lends to my earlier question of ceramic caps as well just a couple posts back.

on my siggen, i am using internal modulation, i thought that would be sufficient.???
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#49
tbone
just saying 'typically",, when measuring the voltage at the speaker, how much voltage are you seeing?

i was for the sake of convienence measuring from the headphone jack paying no attention to backing out the signal.
i was lured in by the increasing voltage i could see at the headphones and where i am now, i can see 3.5v there.

My simpson 360 walked on me (a friend must have borrowed it) so i am stuck with a super cheapy analog meter which the lowest scale is 10v.
using my digi meter i can range in milli volts easily but i would like to see the needle movement.

what target range of voltage are you all typically using to peak IF's?
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#50
The headphone jacks are a good test point, but the issue here is that you can't hear how weak the signal is, and how much it increases as the tuning peaks. 3.5 VAC seems high and seems to indicate you are using too much signal. You could turn on the speaker and listen to the signal and switch back, but I always find it best to measure and hear what you are doing. With a weak signal the volume won't be that loud.

As far as the caps go, without knowing what values were in there it becomes an experiment. Nothing wrong with using what you have to find what works, but then I would install permanent mica caps.

If the sig gen has an internal modulation tone, that would be fine.
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#51
yesterday i muddled through all my vintage domino caps to lay them out in catagories so i can bag and tag them.
i discovered this was a good distraction beacause i have about 12 different pico farad sizes. i thought i only had about 3 or four.
these come from the 20$ extra large tote i bought at a flea market along with a 60$ somewhat inoperative S38-d hallicrafters which motivated me into ultimatly fixing my grand dads Philco.

on my s53-a on the T10 IF , i have two 200pf caps installed to replace the old mica caps.
my volume when i am on a station is rather weak., my volume knob during this test was at max but by ear feels like 50 or 60%.
i touched various caps across the pri and secondary experimenting with what size would raise the volume ultimatly increasing the capacitance.

i have dozens of 1500pf, 22pf, 10pf and a couple 200pf, a few 50pf and more domino caps. i am actually considering building myself a Decade Cap and Decade resistnace box.
i knew earlier that 100pf across the coils of the IF was not doing the trick a few days ago,, and during that time a few days ago i added an additional 100pf across each coil or inductor or whatever we would classify it as...

yesterday i bridged an addtional 10pf across one of the coils and my volume of a particular local station increased slightly with the knob on max.
I added another 10pf and volume came up more.
keep in mind i am just touching these caps by hand.
i start over with a 22pf and volume comes up more.
so......... i take 2) 20pf caps parallel them together and touch 40 more pf across my 200pf i have soldered in to now total 240 pf.
volume came up even more.

i twisted on another 10pf to my two 20's.
i now parallel 50pf with the 200pf and volume came up.

so i bridge 3) 20pf caps across the 200pf and volume still came up.

so i bridge 4) 20pf caps across the 200pf and volume started to go DOWN.

as my slugs are postioned right now with both slugs bottomed out on T10, i assume that the set is trying to tell me more information.

in order to enable me to back off on the slugs CCW, and if this is an inductive reactive circuit,,, XL=2piFL then in order to reduct inductance (since now i am at max), it seems reasonable i would install 250 or 240"ish" pf caps then re peak this IF. 260pf works best now with the slugs bottomed out.
i am thinking doing dual 240 or so pf caps would allow me to turn my slugs ccw.


on the other side of the fence i want to mention something that has me second guessing my assumptions.

if i were to just simply ignore all this bla bla about inserting experimental cap and just discuss "what the set does with i open the tuning cap, here are my results....
when i inject 455kc and tuning caps open, with max volume the noise out of the speaker is inbearable at max.
I know i am wrong before i say what i am about to say but............... with only 200pf across the T10 if, i would expect that the signal generator to be low volume as if i were on a local broadcast station yet it is way loud.

why is it with 200pf caps on my T10 pri and sec, i have low vol condition on am stations yet too loud when the sig gen is inserted?
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#52
well, i did up some 240pf caps on each side of T10 and it did allow me to re-peak the IF's although i was surprised that i was not really backing off on the IF's as much as i was expecting.
i added the siggen and kept the volume knob low where it showed 1vdc on my meter plugged into the headphone jack and headphone selected.

in the proper sequence i was able to peak in another tenth or two of a volt across all six adjustments by going ccw

time to re-string this puppy, get the pointer setup on teh braodcast side then move on to learning how to align the rest of the radio.
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#53
UPDATE,
had another symptom that i was not sharing with anyone because i did not want to add it to the growing list of odd ball reactions this set was giving us.
I did not feel it was too important and frankly i would have felt bad adding it to the list of things i knew i would need help on. I was greatful to get help with the high level problems i was having, let alone nit pick about minor issues.

Since day one out of the box, with the radio on and sensitivity all the way CW, the volume control was spot on what i would expect.
If i rotated the sensitivity knob slightly CCW, the entire speaker output would go completely down. Lets say that rotating the Sensitivity knob 20deg of its total 320deg range would totaly null the speaker to zero audible output.

I worked on the IF T10 by inserting 240pf caps to remedy the fault of silver mica disease.

I noticed the sensitivity knob still had the same problem and i had a gut feeling this is not the way the factory turned out the radio as new.

i studied the circuit and with some clues Terry gave me a began another adventure down a rabbit hole for no other reason than standing a chance of learning something new.

It turns out what i suspected was correct.

I ordered some pico farad caps from Gary at PTOTP and he tossed in my order some random Automatic Corp IFs (branded as Stag) based on some pics i sent him.
these are NOS Stag brand IF's and the resistance on the pri & sec some were 17ohms and the others were 15ohms.

My orginal T10 IF pri / sec resistance was 9.5ohms. I was assuming this was a correct value but to test my theory on how it affected my sensitivity knob i did some tinkering.

What i know is my other two IF's (T11 & T12) resistance on pri / sec are reading about 15ohms.

the manual tells me that two IF's are the same pn, and the other is a different.
I cant tell by the manual and the actual set which is correct. The manual says T10 and T11 are the same but T12 is different.
T12 resistance is the same as T11.
T10 is pysically stamped with a different pn than T11 or 12. Confussed yet?
dont feel bad, i still am and So is Mr Chuck Dachis the Hallicrafters expert.

I totally tore out all my capacitor test subjects on T10.
I removed the IF completely because i just kept coming back to the idea in my head that i believed something was slightly bad about my T10 inductor windings be it corrosion, wear and tear or just plain ole kaput.

I installed one of Gary's Stag IF's which i picked out to be the 15ohm pri/sec variety.

Like magic, this cured my sensitivity knob response. Now the sensitivity slowly and more linearly adds in what i want to call bass or muffle.

with the old if, barely rotating the sensitivity knob cut out all sound.

now that the IF is totally replaced with a nos type, its working like i "think" it should.
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#54
the next thing i did was last night, i ran through the entire alignment process.

At this point have have a broken string on my dial needle and it occured to me that to make thing difficult on myself i should do the alignment the hard way.

example, and i am sure this is all basic stuff to you all but to me, im by myself with no one but this board for help.
let me know what you all think about the step by step i did below... i found it very interesting.
-at this point i have all my IFs peaked out. i had my speaker on and my meter set on millivolts.
-i set my volume knob up to make the meter show 100mv. (keeping in mind the advice earlier from Tbone)
-i followed step 1 and 2 of the instructions and peaked out the IFs and was able to achieve about 150mv after the last adjustment.
**step 2 isnt working all that well, its for the side band CW adjustement,, i will have to come back to that later... this will remain an open topic as i discover if its even worth my trouble. My S38d does a way better job as CW than this set is doing. From what i can see, apparently the S53a does not have a good CW function.

On to step 3, instructions say to set my needle to 1.5mc, my freq gen to 1.5mc then ajust some caps to peak the output.
wash rense and repeat using 600kc.
(i assume this is to ajust the low and high end of the broadcast bands).

so... i move on into step 3(A) setting up High end of broadcast band like this...............
-Open both the fine tune and major tune cap.
-turn on feq counter then connect it up to the set (through a 300ohm resistor at A1, and using chassis gnd.)
-rotate major tuning cap till my freq counter reads 15455000 and stays there steady as can be then disconnect.
-connect feq counter up to my freq gen and dial in a steady 1500kc then disconnect.
-connect freq gen up to the A1 and chassis.
-turn up volume till i hear the tone at the speaker and adjust volume control till the meter reads 100mv.
-peak the two caps per the instructions and observe the meter agrees with what i hear wtih a goal of increased voltage.
-turn down volume.

Step 3B (set 600kc low end of broadcast band............
-turn on feq counter then connect it up to the set (through a 300ohm resistor at A1, and using chassis gnd.)
-rotate major tuning cap till my freq counter reads 1055000 and stays there steady as can be then disconnect.
-connect feq counter up to my freq gen and dial in a steady 600kc then disconnect.
-connect freq gen up to the A1 and chassis.
-turn up volume till i hear the tone at the speaker and adjust volume control till the meter reads 100mv.
-peak the single cap per the instructions and observe the meter agrees with what i hear wtih a goal of increased voltage.
-turn down volume.

contine on with same process for remaining steps 4-7.

When i got done here is what i did last night.

i hooded my freq counter up to the set with the target station of 960AM band.
-hooked up freq counter and adjusted main tuning cap to 1415000hz.
-disconnect the freq counter.
-leave radio on but volume all the way down for the night for no other reason than to make sure its going to play nice and basically to see if its actually fixed or not.
My local station 960 washes out around 8pm at night and it seems to "Wash" back in around 9am.
MY expectations are that when i walk out in the morning to turn up the volume, I will expect to hear AM band 960 coming out of the speaker.

tomorrow has come and so the results are this.
I turned up the volume and i could hear 960 on the speaker and a tad of a sign i needed to move the main tuning cap a hair or two.

this was a test of sorts to see if my above process was possible and to verify if my work panned out or not.

now i can place the dial needle with confidence because i also verified a high and low end station was matching up to my frequencey counter.

thoughts?,,,, sorry so long.
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#55
a few completed pics.
I decided a hinged bottom cover turned out to be a bad idea so a clear cover is now in its place.

From the factory you would have a solid metal bottom which i felt was a bad idea, having access to the components is better.
A clear cover was more for the fun of it than anything else.  Chance is young but one day he will have his own kids and they will be interested to see the works inside as well.


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