SUPERSTAR 360FM EPROM

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mm3stb
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Re: SUPERSTAR 360FM EPROM

Post by mm3stb »

I've just tested checked the voltages at TP2.
Ch23: 7.83v
Ch24: 7.89v
Ch25: 7.96v
Ch26: 7.92v
Ch27: 7.92v
Ch28: 7.91v
Ch29: 7.92v
Ch30: 7.92v
Ch35: 7.93v
Ch40: 7.94v

So i guess i need to adjust the vco?

I've got the wax out. should i be screwing the core in or out?
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The Defpom
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Re: SUPERSTAR 360FM EPROM

Post by The Defpom »

Yep, you need to adjust it, make sure you use the correct size screwdriver to avoid breaking the core.

Monitor the voltage on CH40 and adjust the VCO until it reads 7V, then recheck on CH1 of the lowest band to make sure you have at least 1V there.
zodiac
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Re: SUPERSTAR 360FM EPROM

Post by zodiac »

You'll find TP2 just at the back of the PLL's pin 7, it's R126, 27k.
It's looking like that's all that's wrong with it and the other Eprom that was in was a good one maybe.
With a bit of luck you'll have it working again soon Richard.
Anybody on 40 to give us a rig check PLEASE.
How far is it.
Twice it's length from halfway.
mm3stb
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Re: SUPERSTAR 360FM EPROM

Post by mm3stb »

The old eprom worked fine for a while. it was in the radio when i got it.
So when adjusting the VCO should i be screwing the core in or out or should i just wing it?
When adjusting it should i just monitor the volrtage at TP2 until it rises or is there a set voltage i should aim for?
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Re: SUPERSTAR 360FM EPROM

Post by The Defpom »

You will just have to adjust it and watch the voltage, like I said in my earlier post, aim for about 7V on the highest channel the radio has got, and check that you have at least 1V on the lowest channel the radio has got.

The slug could need to be turned either way, as it depends on where it is set now, it is always a case of turning it to see what happens, you will not need to turn it much, usually only 1 turn is enough, but it depends on how far out it is, what I mean is dont just go and screw the slug all over the place, make small adjustments.

I would say the easiest way for you to see what is happening would be to put the radio on CH20, and watch the voltage, you want it to drop by about 1V, when you have done that go to CH40 and check that you have about 7V, and adjust as required.
mm3stb
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Re: SUPERSTAR 360FM EPROM

Post by mm3stb »

so i am aiming to bring the voltage down rather than up? As i am geiing 7.94v on Ch40uk

Thanks
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Re: SUPERSTAR 360FM EPROM

Post by zodiac »

Yes that's right.
If you look at the voltages you have given above there is next to no change between channels 23 and 40 as you have reached it's limit.
The PLL runs at 8v so the VCO cannot operate above that, you should see a small increase in the voltage as you change channels from the lowest channel to the highest channel and as it is it cannot do that, it's too high.
How far is it.
Twice it's length from halfway.
mm3stb
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Re: SUPERSTAR 360FM EPROM

Post by mm3stb »

SUCCESS!
I have Ch1 low to Ch40 uk. Adjusting the VCO did the trick
Thank you so much for your help.
Now for the 4k7 VR. It states connect to "wiper of course tune" Where should this be connected to? Also the radio is slightly off-frequency should i put it back on frequency before adjusing the 4.7k VR if so how do i go about that?
mm3stb
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Re: SUPERSTAR 360FM EPROM

Post by mm3stb »

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zodiac
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Re: SUPERSTAR 360FM EPROM

Post by zodiac »

KC.png
KC.png (18.67 KiB) Viewed 20875 times
Connect a wire from the 4.7k variable resistor to the unused hole for L35 at the front of the board, this leads to the centre of the KC shift. Connect another wire to 0v Grnd back to one of the other pins at the VR and adjust the VR for the UK off set.
How far is it.
Twice it's length from halfway.
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Re: SUPERSTAR 360FM EPROM

Post by zodiac »

Richard,
I forgot to mention that one of the wires from the VR needs to be wired to the same switch as the one you are using to switch to the UK band, it goes on the other pole or other side of the switch.
The switch should be a two pole switch with three pins on each side making it a two pole switch, see your drawing with the Eprom fitting instructions.
As for aligning the radio you'd be better to take it to someone with the proper equipment and experience of working on the radio, the adjusting slugs are very delicate and brake easy.

Dave.
How far is it.
Twice it's length from halfway.
mm3stb
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Re: SUPERSTAR 360FM EPROM

Post by mm3stb »

OK,
I have Wired it up as per follows. L35 - centre pin on switch - top in on switch to middle leg of 4k7 VR - right leg of 4k7 VR soldered to can L15.
When i try to adjust the frequency on ch1 I can only get it to go as high as 27.60049 instead of 27.60125 with VR turned anti-clockwise. When turned fully clockwise i get 27.59307.
I have check that corse tune is in the centre position and KC shift is off

Any ideas where i'm going wrong?

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Re: SUPERSTAR 360FM EPROM

Post by zodiac »

Richard,
From what you've said it would appear to be wired correct.
The coarse fine tune should both be at the 12 o'clock position when making the adjustment to the added 4.7k VR.
You did say that the radio was off frequency and maybe that's the reason why it won't tune in but if you look at the maths you've given there's only 0.00742 of movement from one end to the other, it should have about 4 to 5KC's on the 4.7k VR. So something is not right and even with the radio off frequency it would still move a lot more than it is.
Check the wire you fitted in the empty hole for L35 and follow the track to the left turn the radio over and you should see the screen print above the wire that's in that hole, it has (M) above the wire and COSE below it.
The wire that's in there goes direct to the centre pin of the coarse tune and saves you the trouble of removing the front of the radio to take the control out to fit the wire on.
Also the AM/FM power adjuster VR13 is turned up full, I'd turn it down if it was my radio.

Dave.
How far is it.
Twice it's length from halfway.
mm3stb
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Re: SUPERSTAR 360FM EPROM

Post by mm3stb »

Thanks, will give it a go when i next have the soldering iron out. the radio is just slightly off frequency so i would of thought the trimmer would of compensated for it. Thanks for the advice on VR13. Will turn it down. Everything is the way it was when a got the radio with the exception of the relay board and old Eprom. It came from a tinkerer me thinks.
Will keep you updated
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