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Radio: Ranger Superstar 158EDX MOSFET model.
PCB Number: EPT690010D
Condition: Stock Radio only modification 11-meter conversion.
Symptoms: Frequency counter some times show 10.695 MHz on some channels, FM TX sounds off frequency, TX carrier not very stable.
What is working: All voltage regulators are ok, RX/TX switching is ok,
Skill Level: Medium

You are welcome to ask me any questions that are specific in nature just as if you were troubleshooting the radio.
The Schematic to solve this problem can be found hear,
http://www.cbtricks.com/radios/rci/ss_1 ... et_sch.pdf

Do not be shy and let us have some fun!

Rick Jackson (Euro Radio Co).

The first thing I would do is press around on board to see if there is bad soldering. Then align the PLL and see if symptoms remain.
But I bet its not quite that easy.

Are voltages correct on IC2 (VCO) and IC9 (TX Mixer)?

Timrim,
There are no bad soldering joints.
Re-Alignment did not help.
The voltage at IC2 is within 5%
The voltage at IC9 is within 10%

What on one else trying.
Don’t tell me this is to hard.

Not having that issue with my 158 other than it not staying on freq. when cold I will be watching to see what the outcome is.Rick I think that this new line of posting is great, makes one think.
Bob

I think the fault is D53.The D53 is after L23.

Dxswe,
D53 is ok.
This diode is only used on AM and FM, and the fault is on all modes.

Sorry Rick, I have been busy with a sick TS-940SAT, or I would have been offering more ideas in here, the SS-158EDX is one of my favorite radios!

Ok, check the following parts:

Check the following varactors> D-99, D-100, D-148

Check the following caps> C103, C107, C112

You said that sometimes that the frequency counter sometimes reads 10.695, is that only on the radios counter, or on an external counter on transmit? Also, you said that happens on some channels, is there any pattern? Like high channels or low channels...etc..?
When the counter displays 10.695, how does the radio act on receive and transmit?

Timrim,
The Varactor diode D99, D100, and D148 are all ok.
The Caps C103, C107, and C112 are all ok.
Yes, the radios own frequency counter shows 10.695 MHz from time to time.
There is no pattern to which channels was playing up, it can be Hi or Low band channels, it is total random.
The radio was playing up on RX and TX.
TX was very unstable from time to time, but most time in was ok.

I feel it is time I had a go..

Check for frequency problems at Pin 2 of the PLL, if it is noisy or erratic then lift R121 and inject a stable 4.00V into TP2 (pin 5 of IC2) and monitor frequency at pin 2 of PLL, if problem persists then check C97, C98, TR29, TR28, if they are OK then replace IC2.

If frequency is OK after lifting R121 and injecting 4V then suspect PLL or 10.24Mhz crystal fault.

The Defpom,
The frequency at Pin 2 of the PLL is noisy if view on a scope.
Inject voltage into TP2 did not help, still noisy, but looks ok on a frequency counter at Pin 2 of the PLL.
C97, C98, TR29, TR28, and IC2 are all ok.
The PLL IC3 and the 10.240 MHz crystal are ok.

Note
Maybe this one is a bit hard to sort out.
Maybe I should tell you all the answer, lets see what happens in the next few days.

SOUNDS LIKE THE 10.695 MHZ CRYSTAL FILTER IS BAD

Ramblingman,
The 10.695 MHz crystal filter is ok.
Even if the 10.695 MHz crystal filter was bad it would not explain, why the FM TX sounds off frequency, as the crystal filter is not used in FM.

I may as well have a wild guess at this one..

Would you either test or replace these caps:

C95 C116 and C117 and see if that would help.

Regards, Jim

Is the frequency noisy at pin 10 of IC2 ? (when using the injected 4V at TP2)

Are RA3 and D149 OK ?

Is R140 correct value ?

Euhara,
C95, C116, and C117 are all ok.
-----------------------------------------------------------------------------------------

The Defpom,
The signal at pin 10 of IC2 is noisy.
RA3 and D149 are ok.
R140 is the correct value.
-----------------------------------------------------------------------------------------

Note
Maybe this clue will help.
There is less noise at Pin 2 of IC3 when you go to a lower channel on each band and when the radio is cold, there is very little noise.

Check C99, R129, D42, D146, R130, L47

Also, does lifting R126 change the amount of noise at pin 2 of IC3?

Rick, on a side note... some corrections for a later revision of the diagram.

Your diagram shows R124 as 10M, another diagram I have shows it as 10K, also IC2 is not marked with a part name (IC090), and L16 (22uH) is not marked as such (between C116 and C117)

The Defpom,
C99, R129, D42, D146, R130, and L47 are all ok.
Lifting R126 makes no change the amount of noise at pin 2 of IC3.

Scott,
Thanks for pointing out my errors.

I am not sure about (R124) I will need to check in a working radio.

No early EPT690010Z diagram IC2 was marked with a part name (IC090) but on the later chassis this was dropped and the new number is EPF000211J.

I will put the choke (L16) ref number on my next update.

Also JP237 requires further investigation, your diagram shows it as 100R, the other diagram I have here shows it as 1K, yours could well be right and this one could be wrong, R124 and JP237 just need to be confirmed.

What happens to the noise and radio function if the frequency counter is unplugged from J22 ?

The Defpom,
The fault is still there with the frequency counter unplugged from J22.

I have check out a new 158EDX and R124 is indeed 10M and JP237 100R.

I think the Sch you have is for the ETP6900010Z, which was only in production for 4 years and is now some 10 year old.

Yes, it was for a Z version, glad that yours is OK, just surprised by the large difference in component values between versions.

You called this one a "Medium" level problem, you may want to change it to a "Tricky" instead

I am obviously missing something...

How about cleaning the channels selector, in case of dirty contacts causing the PLL to rapidly switch frequencies.

I think there is a cap connected to the X4 (10.6975)crystal that has failed I think C136 should be checked if not already done.


Jim

The Defpom,

You called this one a "Medium" level problem, you may want to change it to a "Tricky" instead

Well I thought the fault was easy to sort out.
I found the fault in less than 10 minutes with the aid of a scope, and the total job was 20 minutes, which included check and setting up the PLL section.

The channels selector was working just fine.
----------------------------------------------------------------------------------------------------
Euhara,
No C136 is ok.
----------------------------------------------------------------------------------------------------

Note
The radio was only two weeks old when this fault started to occur.

Rick wrote:The Defpom,

You called this one a "Medium" level problem, you may want to change it to a "Tricky" instead

Well I thought the fault was easy to sort out.
I found the fault in less than 10 minutes with the aid of a scope, and the total job was 20 minutes, which included check and setting up the PLL section.


Note
The radio was only two weeks old when this fault started to occur.

Then I am definitely missing something...

Are you sure that there would have been noise at pin 10 of IC2 when it was running off of an injected 4V (clean) supply onto pin 5 ?

At the moment it looks like a loop problem, but breaking into the loop should have changed the noise problem if it was a fault with the low pass filter out of the PD, the PLL, or the mixers feeding the PD input.

Unless you are going to say it was just a bad alignment of L15...

The Defpom,
Inject a clean 4.00 volt into TP2 did not help the signal at pin 10 of IC2 it was still noisy.
L15 alignment was ok.

When you say "tx carrier not very stable" do you mean the frequency, or the carrier level ?

I need to step back and look at it from a different angle...

Also how clean is the DC supply on pin 8 when viewed on a scope ?

There aren't any component leads touching each other on the PCB are there?

Also, are there any cracked traces ?

The Defpom,
The carrier level shows instable on the spectrum analyzer.
There are no component leads touching each other.
There are no cracked traces.

The DC supply is not very clean at pin 8 (IC2) when viewed on a scope.

Scott, you are getting hot.

I that case I would say to check C170, D72, D73, Q35, Q37, C173, R214, R213, R215, R218.

Is zener diode D-70 breaking down? what does the scope tell us when put on Q-30 and Q-31?

The Defpom,
I did say that all voltage regulators are ok, RX/TX switching is ok,
All the components C170, D72, D73, Q35, Q37, C173, R214, R213, R215, R218 are ok.

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Timrim,
Zener diode D70 is ok,
Q30 and Q31 are ok and have on noise on them

OK, check C105 and C106 then...

Scott beat me to it, going by the clues I was going to say check C106

Jim

The Defpom,
Bingo, we have a winner.
It was C105.
On a cap test it show just fine, but with very hi impedance moving coil meter it show just under 1 meg.

Well done Scott.

You did well to find that in 10 minutes, it would have probably taken me about an hour to find that cap as being the problem... it is not exactly the sort of part I would expect to fail in a new radio.

OK, onto the next one I suppose, lets see what I can put together this time, I will have a look through my notes and find something suitable.

hi all dose anybody know how to mod the echo in the ss-158edx,wheen i meen mod i ment alter the echo so as when radio is keyed up the echo continuese to reverb till it is un-keyed,
so all in all what i want is a continuese reverb till its de-keyed,speed is fine its the length ov time before it dies off,any ideas many thanks

serial No-T70600514