My old friend President Jackson.

[Robb]

well now today this radio is all over the place, just when i got the suv all warmed up, made some contacts, then after about 30 min the radio was off freq again, then later again, and again, seems a guy is always having to adj the clarifier. its too bad because when its on freq it is a great workin radio.

thinkin this radio is going in the closet or ebay. if you are a guy that always likes to be turnin knobs this is the radio for you,,lol

oh well, at least it wasnt too expensive.

it might just be the conditions from a cold vehicle then warming up and hot air from the heater in the suv?? maybe if the radio was used indoors it would be more stable, but going from 0-20*f to 80*f in a vehicle its all over the place.

Got a fix for that!
I'll post it up.

 

[Robb]

The fix for the drifting SuperStar JA

If you just touch or even so much as breathe on the 14.010mhz Loop Oscillator crystal, the freq will shift 2khz! Not saying this fix will help in extreme temp changes because I haven't checked that yet. But I'll bet that it will shift a lot less. I can tell you that it won't shift anywhere near as much as it used to - by a far cry. I can now touch the crystal and the coils and it won't even shift 10hz!

The following pictures are 'before and after shots'.
All you have to do is link the Loop Oscillator tuning coils to the 14.010mhz Loop crystal. The coils will take solder. but the crystal won't as it is nickel plated. You will need to use a Dremel tool and nick a corner of the crystal so that you break through the nickel plating; then that nick will take the solder. Don't break through and make a hole in the crystal; just nick the surface. Then let it all cool for five minutes or so. Then, you will have to re-tune all three of the Loop Oscillator coils once more. Just allow your freq counter and radio warm up in a warm room for 15 minutes before you do the alignment. Don't forget to center your Fine Clarifier control too.

This radio is FAR more stable now.
Solid mod.


This works . . . Before . . . and After . . .

 

[camaro1]

ill try that tonight!

 

[The Mad Scientist]

Instead of going through all that why not just replace the crystal with a high stability one? Having to add a ground like that makes me beleive that the crystal is on it's way out and to old to be of any real use, and or a possible grounding issue as well.

Using hi stability crystals made a world of difference in the older galaxy radios and I wonder if they would make the same difference here?

Good job at stabilizing it.

 

[Robb]

Instead of going through all that why not just replace the crystal with a high stability one? Having to add a ground like that makes me beleive that the crystal is on it's way out and to old to be of any real use, and or a possible grounding issue as well.

Good job at stabilizing it.

Because the problem isn't the crystal; it just needed to be grounded to its corresponding coils. I think that modding as I did proved that to me.

Even new crystals aren't exactly on freq and you can even tune them to freq if you remove in of the small pf value of the two stabilizing cap and put a compression cap in its place. That works for the Reference oscillator crystal (eg. the 10.240mhz xtal); not for the Loop oscillator crystal.

But that isn't the problem here. The mfr just didn't do the grounding link is all.

 

[The Mad Scientist]

Naw, it isn't a mutant hybrid. It is a SuperStar JA. Question is; when did they come out? I can tell you that it had to come out just a short period after the original Jacko did. My guess is 1984; the serial # on the back begins with a '4'. Again - a guess. But the evidence from visual finds on/in the chassis dictate that must be so.

Ok, Then this is that long inticipated rig that everyone has been waiting for that never made an entrance. A n.o.s jackson board that has been tweaked to use both old and new components, and ended up worse than the origonal:glare:.

And if they did in fact come out I am sure someone would have seen it. Perhaps they were introduced to a select few and then for some unkown reason shelved all these years.

 

[The Mad Scientist]

Because the problem isn't the crystal; it just needed to be grounded to its corresponding coils. I think that modding as I did proved that to me.

Even new crystals aren't exactly on freq and you can even tune them to freq if you remove in of the small pf value of the two stabilizing cap and put a compression cap in its place. That works for the Reference oscillator crystal (eg. the 10.240mhz xtal); not for the Loop oscillator crystal.

But that isn't the problem here. They just didn't do the grounding link is all.

Ok, I can see that. So how much of the shift that is left do you think could be cleared up with a hi stability crystal cut for that frequency?

 

[Robb]

Ok, I can see that. So how much of the shift that is left do you think could be cleared up with a hi stability crystal cut for that frequency?

Doesn't shift very much - if at all in the same room after turning it off for fifteen minutes like it used to.

Naw; it is just fine 'n dandy now.
A high stability crystal isn't needed at this point

 

[The Mad Scientist]

Went back through the pic's of the origonal and I don't see this ground in place.

 

[The Mad Scientist]

Doesn't shift very much - if at all in the same room after turning it off for fifteen minutes like it used to.

Naw; it is just fine 'n dandy now.
A high stability crystal isn't needed at this point

Why would you think that?

Ok, This is good if it is going to be used as a base in a temp controlled enviorment. But I am sure that won't be the case if used mobile in a colder climate. Maybe someone could test this out. Subject it to temps around 10 degrees f and see how she does after that modification. My geuss is you would be right back in the same boat.

At least it has been stabilized enough for base use.

 

[Robb]

Why would you think that?

Ok, This is good if it is going to be used as a base in a temp controlled enviorment. But I am sure that won't be the case if used mobile in a colder climate. Maybe someone could test this out. Subject it to temps around 10 degrees f and see how she does after that modification. My geuss is you would be right back in the same boat.

At least it has been stabilized enough for base use.

The point is that it has stabilized. Not the same boat; not even on the same lake. I made no other claim one way or the other. Since it is far more stable now, it should be somewhat more stable in a mobile environment. Probably no better nor worse off than a Cobra 148GTL/Uniden Grant XL would be. I am in CA; 24f temps are pretty rare in the flatlands

ANY radio will have shift due to temp change. However, the CPU-controlled radios like the RCI 2950 or the Magnum 257HP will have far less as the Loop Osc function has been absorbed into the CPU function..

 

[Robb]

I hooked this radio up to the Hp 8656B Sig Generator. SSB receive can easily hear a .25uV/30% modulated 1khz tone as well as just move the needle by just a hair. Then tried it with .1uV and it could still be detected by ear. The receiver section is working quite well; even xlnt IMO . . .

 

[The Mad Scientist]

That's correct. But then again we are not talking about any other radio we are talking about this one. And yes, I agree that it should be more stable but by how much? I understand that you didn't make a claim one way or the other but how do you know that it won't be as bad in a mobile enviorment if you cannot test it to that fact? All we know for certian is that you have stabilized it at room tempeture.

And I am also wondering being have had the origonal jackson and had no trouble with it drifting as you have observed prior to the modification that you just did as to why the origonal does not have this grounding and this one needs it?

Any crystal controlled radio WILL benefit from the addition of hi stability crystals and would operate the best they will be able to short of adding a TCXO.

 

[Robb]

That's correct. But then again we are not talking about any other radio we are talking about this one. And yes, I agree that it should be more stable but by how much? I understand that you didn't make a claim one way or the other but how do you know that it won't be as bad in a mobile enviorment if you cannot test it to that fact? All we know for certian is that you have stabilized it at room tempeture.

And I am also wondering being have had the origonal jackson and had no trouble with it drifting as you have observed prior to the modification that you just did as to why the origonal does not have this grounding and this one needs it?

Any crystal controlled radio WILL benefit from the addition of hi stability crystals and would operate the best they will be able to short of adding a TCXO.

The fact that it has become far more stable can only mean that it is far more reliable than it was before the mod. How this translates to a cold mobile environment is not in my corner to determine. Not a gambling man; but my money is on it being more stable in a cold environment simply because what i consider a very serious deficit in the radio had been changed for the better.

Camaro1 said he would mod his radio and give it the test. We will have to hear from him and wait. Don't expect anything miraculous; just better than before.

Doubt there too many of these radios even being available from those that retailed them at this point in time . . .

 

[The Mad Scientist]

I hooked this radio up to the Hp 8656B Sig Generator. SSB receive can easily hear a .25uV/30% modulated tone as well as just move the needle by just a hair. Then tried it with .1uV and it could still be detected by ear. The receiver section is working quite well; even xlnt IMO . . .

Well this is good news.