Galaxy saturn ept360014b vr16 low power will not adjust

[Handy Andy]

Believe it or not, your parts list checks out ok.

The Losses are due to factors further upstream from the Final and Driver - or Down Stream if you are having heating up issues - but SSB signal - when you have TOO high of a signal gain from a previous stage - kills the signal - it degrades it - from OVERAMPLIFICATION further down the strip from where ever this caused the original condition.

So that means - since IF is mixed in from TWO locations - the inputs from BOTH locations needs to be EQUAL.

That may mean a resistor Check /Verify - swap - fix - at two locations to help balance the PLL IF and Clarifier's IF to be equal and balanced so the mixing can occur with less distortion. Tweaking coils is great to help but only go so far - that is what they're there for to take the unbalanced and finely tune it to meet level - 2 - level so the BYPRODUCTS are less and you don't get too much distortion.

I can tell you from experience - R231 and R232 - they are a *<EXP>* to find but are two resistors that enter IF signal into L43 and L44 - one "starts" at 100 Ω (R231) while the "other" is 560 Ω (R232) - and that is on their parts list, but in real life? No not always those values - L44 or L43 can peak in varying amounts of RF at any given moment in production forcing them to change on the Fly - so they may have subbed values - or if the radio passed QC and was sent out (if it was even checked) - does not mean it was verified - and they just may have kept those two resistors as listed on the schematic.

This becomes the problem for you when AM or FM modes are great, signal looks good and have power.

Why does SSB? SuX? It's in the finer details of SSB mixing, it's trickier, you have IF from one section flooding the Mixer with it's RF, the other side has IF that arrives when you talk - so the mixing effects has to take the weaker signal and not over amplify the other IF in the process - the dynamics of mixing - so the FILTER then has to do all the work in removing the lower IF ringing but allow the 27MHz mixed stuff thru - so if you understand this entire paragraph - you're doing better than most.

So L43/L44 mixer - and possibly R231 and R232 will have to be altered (by age too) to balance the IF signal better.

 

[Handy Andy]

I have to break this apart into two sections...

Part II

Are you trying to Hi-Fi a Saturn? You can, but not at the expense of SSB - so DON'T mess with the Balanced Modulator too much - it will generate more mixing products that will WEAKEN your signal you're trying to amplify.

So if you've changed caps or put in some changes to the Balanced Modulator (AN612) or even it's input caps - this will work AGAINST you when you want to Hi-Fi a radio - so don't overdo the Mic amp section for it will do the very thing you're NOT wanting the radio to do.

 

[BAGEBOY]

Thanks Andy No I don't want the Saturn Hifi I am happy with a descent working radio..so do u sugguest changing R231 R232 if so should I use theschematic value or ???? Should I change the AN612. I will follow your lead

 

[Handy Andy]

Ok, here's the problem - or one of the problems(s)...

If AM and FM seem to modulate ok, but SSB seems weak - then you have research two "forks" the Audio signal goes in...

​

One; in AM (or FM depending) it goes to the AM Regulator and is processed and goes to the Driver and Final.

In FM the PLL side gets modulated as Deviation.

If everything works ok, you get equal levels of signal from 3 (yes THREE) sources - two from the IF (PLL and AM / FM Section).two go to the Mixer S042P - while the 3rd is your AM Regulator Audio and power - since none of the IF's mess with the AM output - you get predictable results.

It's harder to get these SAME results in the SSB - where you have one IF that is constantly on - sending signal - to the mixer THRU L43 - awaiting the other one that is arriving from FL3 THRU L44 - into the mixer -

So what does the mixer do? Simple. Amplifies the one signal (PLL thru L43) and keeps it on - like a carrier - waiting for something to appear on L44 and then try to amplify that EQUALLY into a 27MHz signal. Only it has to discard that carrier generated in the mixer - it's only 1/2 the ENTIRE signal it needs for 27MHz - it uses a band pass filter and balanced bridge internally for that so you don't want to send too much power into the mixer from one while it waits for another - it will have to dissipate that power for that 1/2 while it awaits for something from the other 1/2 - and that Mixer part - is subjected to age thru it's lifetime. (L42/C182 accept output from the Mixer out)

The critical part here, is FL3 - if it's old, or isn't tuned right to "match" Dollar for Dollar - All Bets are off...
The Output of the AN612 HAS TO BE on Frequency, so the PLL IF of CARRIER and the two sidebands of IF from the Clarifier side - one "side" of the audio information is saved - one side is saved to go thru L44 into the Mixer, the other two are discards - thrown out.

FL3 is used by L44 and Clarifier IF - the Balanced Modulator sends output all the time to FL3 - even in FM and AM so you can have the L43/L44 combo make a carrier for 27MHz - the only time it doesn't send audio - is when it is in AM or FM mode - it simply "amplifes" what the Clarifier IF sends to it (why you have those 3 frequencies you "peak to" when tuning USB is 1, AM is 2nd and LSB is 3rd)

If FL3 is not correct, or has too much of one being sent to it and not enough of the other - FL3 generates a MIXING result from itself - that is SAPPING AWAY the audio signal because of spectral artifacts involved - the band pass of voice amplified by the Balanced Modulator - is not symmetrical - and you can generate an OUT of PHASE or MIS-PHASE issue where a reflection artifact CANCLES OUT (like an interference pattern) parts of the audio signal. Caused by FL3 not processing the output of the Balanced Modulator correctly.

Too much audio can do this - so watch your output levels and work accordingly - too much audio in the wrong spectrum range of audio - will REDUCE the effectiveness of FL3's ability to pass Audio ONLY.

The two parts of the radio that it uses - to make the 3rd - your audio - work - if they can't be made equal - one side will suffer more than the other. In this instance, L44 and the Audio Side seems to be suffering.

If you're not having "TVI" problems with L43/L44 tuned the way they are, you might need to work further back - to the input resistor network at FL3 - THEN "tweak" and balance L44 and L43 - using the OUTPUT of R232 - you change the value of R232 up or down to rebalance the AM/FM carrier mixing...

So work small steps - recheck the IF tuning for Clarifier - make sure the Audio "tone" of both USB and LSB are nearly the same - Carrier Balance Adjust as needed so you're not thrown off your "center slot".

Locate FL3 - in fact Locate L44 too - there is one trace that "communcates" from FL3 to L44 thru several components. D18 and R232 - there may also be a Resistor - R79 a 10K - kind of a critical component - if it's drifted off in value - can force a change in FL3's performance - also a "band pass" filter is used on the OPPOSITE end of FL3 from the Balanced Modulator...

​

 

[BAGEBOY]

I have dome all this my power on the arm I'd about 40-42 WATTS AM AN 25-30 SSB IS THAT NORMAL OR SSB TOO LOW?

 

[Handy Andy]

Now power is even higher on Am, Woof - this then looks back to being a "spectrum" of audio issue more than power.

So since you've got more on the AM side - hope it's not in spurries'. I hope that you're pushing actual 27MHz and this is not tied up in 2nd harmonics and above kinda' stuff.

What I mean by SSB being low, is the frequencies it needs to amplify - some part of the range it needs doesn't seem to be present...

​

It's band width used to amplify - is rather narrow...like 1kHz in width so that would include from about 500Hz to 1.5kHz - which is more Tenor than Alto (Treble compared to Bass) - if you're Hi-Fi-ing a radio - this spectrum if TOO wide - and it will not amplify well - it will take tones that are closer to it's resonance (being more Bass) because of where you mix (How the Balanced modulator sees this) and it produces in it's artifacts - set up as. It will amplify all the energy there - whether it does make it thru the Crystal or not.

They try to "trim this up" by using the Mic Amp in such a way that it will amplify more speech than wide fidelity audio - like broadcast audio. Not a good idea to have widebanded fidelity on a SSB mode. You can but not with this setup. In the case of these Galaxy radios, They set up the Mic amp to amplify general speech range of tones - so they (these wider ranges of spectrum) would normally get dropped off BEFORE back at IC4 (4558 Audio Side). What gets thru can "color" the results sent to the mixer. But, they wouldn't be noticed until AFTER this stage when the Mixer truncates this sharply - but you produce lower bumps of frequency energy that saps (takes away) Audio power. Your results are; lost PEP you could have had from the speech tones that aren't getting thru because the amplifier is cutting them off.

This could be something as simple as replacing a few older Disc caps with newer ones of one range Smaller in value - say a 104 (0.1uF) is used, switch to a 683 (0.068uF) instead - this reduces the DRIVE. But not by much, just less energy getting sent in to be wasted.

If you have a scope you'd see this as LOWER Fundamentals showing up and you'd see how they get filtered out - and then the strip amplifies what exists in 27MHz after all of this...

You're actually doing great - but use AMC or a little less of the AM Regulators output cap - that 100uF thingy in the back, if you have too much going into AM and FM - it's harder to balance this out...

You're doing fine...

 

[Handy Andy]

This could be something as simple as replacing a few older Disc caps with newer ones of one range Smaller in value - say a 104 (0.1uF) is used, switch to a 683 (0.068uF) instead - this reduces the DRIVE. But not by much, just less energy getting sent in to be wasted.

This is to clarify what I mean by "Drive"...

​

Every stage of amplification needs to have a signal arriving to it- in a SPECIFIC range of energy level - a DYNAMIC and POWER range - so the stage can accept and amplify the signal.

• Brown Arrow - This resistor for example - not only set's drive, but a level of spectrum the easily passes into the amplifier - by affecting the reactance the Capacitor following it will do to the amount of audio in both volume and frequency
• It is a Basic SERIES-PASS filter - which lets the predominate tone the mic cartridge will have produced when you're talking into it - pass easily enough with little attenuation.
  • To save breath - this is similar to a Hi-Pass filter. The Capacitance is tiny values, and uses a higher resistor value than what normally would be used for a PA system where full reproduction is preferred
• When you change the Resistance and or Capacitance - in the Red Circled areas or even the input cap to Pin 3 of the Mic Amp itself - you affect the GAIN of the circuit and how much signal is processed.

Too much of a "good thing" usually is...
IF you don't follow this guide using OEM schematic values - you can wind up getting screwed up audio and an angry customer and laughing operators cheering on the effort.

So take heed of the schematic values - being conservative here helps - especially when in comes to the Audio QUALITY - not content or volume thereof, this is about the Drive level this Mic Amp Shown Above - develops and if you're not careful will also DAMAGE your radio from improper drive and or bias here from messing with values trying to get more from it.

 

[BAGEBOY]

I was going through the radio I found (2)caps replace c195 1000uf change to 4700uf and c194 1000uf change to 3300uf should that make a difference

 

[Handy Andy]

It is not necessary but if this radio is old, can you find or source parts to refresh some of your audio chain parts - both Disc and Electrolytic cap types?

I recommend some of the audio chain gets recapped - so you can eliminate problems from showing up later.

But these caps you mention are power supply input types - to get the "peak watts" like you are with AM - the radios terrific - but the SSB part - that section might need more TLC to get it right.

 

[BAGEBOY]

I saw another saturn today that has capacitors at the bottom that mine doesn't have.Please see photos ..any explanation??

 

[Handy Andy]

Hmm.. Can you spare of photo of that Saturn's foil side?

The caps above in yours are placed as they are to offset space lost on the top side.

Caps themselves also have various tolerances so the caps used in a low-power section like the VCO are very small and can be made with tight tolerances.

It's when you get into higher power and the required power dissipation needs - do the larger caps size and tolerances for a particular value start showing up in many different way and configurations - including their composition - Silver Mica being a popular one to use in power sections.

Silver Micas'

Small Signal NPO's



Hope you're getting the idea ...​

They may have just run out of room on top of the board so they fill in those missing parts for those holes on the bottom side.

 

[BAGEBOY]

I have gotten the power between30/32 watts ssb and 40watts Am
What I have found which I never paid attention to the radio is transmitting on frequency but on the counter it is a bit off in the frequency display only on Lsb Ssb Am is fine .I tried the ssb adjustment but even when it is on frequency the when I transmit I off
...see photos

 

[Handy Andy]

That is the IF and how the counter cacluates from it.

Do you trust the counter or the IF?

Then the counter should have an Xtal "base" that can be trimmed using a cap - by changing it's value can raise or lower the "base counter and sample frequency" by changing the "speed" the crystal works.

Examples are like the FC-347 ...

There are several caps along the route of the Crystal...
VC1 if present is the trimmer you "trim" to match.
They may have done it earlier you're just reseating and
resetting the "Base" back to match the IF and counter together.​

 

[Hawkeye351]

Hello again Handy Andy,
Sorry for my extended absence, but I've been busy getting my test equipment and tools setup and learning how to use them. I am back now with this Saturn issue now that I'm back to working on the radios instead of collecting all my gear and supplies.

I now have an HP Agilent E4411b spectrum analyzer, digital 100mhz oscope (my analog 100mhz is on the way, hp 1740a), esr meter, capacitor meter, etc... Along with a stock of nichicon capacitors of different values (mainly the typical ones for galaxy radios), silicone and other diodes, finals, resistors of different values, desoldering station and other stuff.

As far as this Saturn issue:
I have yanked out the following electrolytic capacitors from the pass regulator section, power supply section, final section:

C195
C194
C190
C193
C150
C151
C145
C146
C604
C703
C702
C174
C164
C165
C166

I have tested them all on 3 different testers, esr meter (v2), longrunner component tester and a standard capacitor meter. They all show below the "worst case scenario" gauge on the esr meter with no issues and shows close to their respective values on the longrunner tester and capacitor meter.

I see no burnt resistors no where in the radio at all, they all still look new.

I replaced the pass regulator and AF regulator facing the pass regulator. I also replaced the voltage regulator on that same side of the board.

I am lost now, not sure where to look next. I see no solder balls, shorts, etc... But that one transistor in the rear right corner near the pass regulator still gets scorching hot within a few seconds of just flipping to sideband, even while receiving on ssb. I think it's called the ssb switching transistor. I had removed it once before and tested it in my component tester and it showed fine, so I put it back in.

Instead of putting these old caps back in, I'm just gonna go ahead and put in New ones since I have stock supplies now.

Still stumped on the weak output on ssb, lights dimming with modulation on ssb and the frequency counter dropping to "0" when modulating on ssb.

I did find a broken ground tab solder connection from the chassis to board next to the PLL on the bottom side (I found that this is pretty typical on most of these galaxy style radios).

Any other steps I should take on this issue? The customer is very patient with me because I've done other radios for him that he was pleased with afterwards. I'm the only tech for 75 miles in my area due to the other decades old tech recently passing away.

The people in my area have been very impressed with my tunes. I tune their radios to an oscope and spectrum analyzer only, I could care less what that watt meter shows. When I'm done realigning a radio it normally comes out with less swing than they had before, BUT they claim my tunes drives their amps harder than before. I explain it to them that the signals are clean and pure now, not wasted power going all over the spectrum is why they get more power out of their amps with less swing from their radios as compared to how it was tuned previously. I've learned a lot in my absence, I have to because they need a good tech, not a hack shop or truck stop cb shop splatter job.

I ran into this same issue on a superstar 3900 recently, and after replacing all the electrolytic caps in the pass regulator and audio section the problem was solved, but this Saturn is busting my chops, lol...

Any help would be greatly appreciated. Thank you for your patience and guidance previously.

 

[nomadradio]

That transistor that gets hot is TR52. It serves to "switch" the big PNP transistor TR51 so that it's saturated and has a minimum voltage drop in sideband mode. A resistor R243 in line with TR52 also gets hot if you don't beef up the wattage rating.

This is supposed to be a sideband-only function. If it gets hot in AM or FM modes, that's a problem.

73