The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

Rick

TR33 must have been change at some time for the wrong one, as NPN would be switch on all the time and RX/TX would be in conflict. I have seen the TR33 fitted in the wrong way round a few times, after the transistor as failed. I use a 2SA1282 in most radios, which use this form of RX/TX switching. A ...

Rick

His the B+ supply to the PLL and VCO free of noise and at the right voltage?

Rick

What is the voltage at Pin 8 of the PLL (IC5)?
What happens if you unhook one end of R171?

Rick

Has R104 a cold solder joint or o/c?.
Has C91 a cold solder joint or bad?

Rick

What is the voltage at Pin 10 of IC2 on channel 19?
Cold solder joint around IC2?
Is the down mix at TP 10 the right frequency?
So Pin 1 of IC2 is noisy Yes?
Is there any noise on the supply line to Pin 1 of the PLL?
Has the VCO coil L19 unstable?

Rick

If you inject 3.00 volts in to TP9 with one end of R207 unhooked, is the frequency stable and free of noise at TP10 or Pin 17 of the PLL?

Is the fault with one of the caps in the low pass filter (PD) C79, C80, or C81?

Rick

When ask for any help it is always best to give the PCB number. If the radio is working ok, I would stay with the bipolar transistors as long as you can, it makes no sense just changing them just to gain a few extra watts. I may find the info you need is on http://www.cbtricks.com/miscellaneous/fet...

Rick

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.

Rick

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. ------------------------------------------------------------------------------------------------------ Timrim, Zener diode D70 is ok, Q30...

Rick

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.

Rick

If you think, my last post was condescending its only because you do not understand. It is no good asking what the voltage should be, as this would not help you. How would it help you if I told you the voltage was too high or to low? It would be better if can tell me the voltages and then I can hope...

Rick

It is no good just replacing a component until you have tested them, this will not help you find the fault . To find out how to test component, do a Google search that may help you. I do not wish to be rude but if you do not know what you are doing, it would be best to take the radio to so one how c...

Rick

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.

Rick

I advised you the components to test on my 10th November post.

Rick

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 s...

Rick

The KEPC-225D is the PCB number, the PLL is at the front of the radio near the channel switch and will have a number like uPD2816. As the S/RF meter is not working in RX and TX, would suggest that you have a common wire broken or you have the SWR/CAL switch in the in the SWR or CAL position and not ...

Rick

Check the meter with a DVM on a diode test, and the meter should move. If the meter is ok then check you do not a cold solder joint or broken wire. If all is ok check the components, I would tell which components to check but you have not given the PCB number. It maybe a good idea to read www.radiom...

Rick

If your radio has a 2SC2166 driver then set the bias for 50mA using TP9 and TP8.
If your radio has a 2SC1969 final then set the bias for 100mA using TP9 and TP7.
Both bias are setup USB mode with no modulation in TX

Rick

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.

Rick

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 (IC0...

Rick

Well this all made me chuckle. About setup using a receiver and a telephone. TP6 is only used to setup the carrier osc in SSB and only in TX mode. The AM carrier test point is TP5, which is the output of the Balance Mod IC6. Ranger has not fitted a TP6 for many years now, and you use the resistor R1...

Rick

That is why I told you it was best to check the current being drawn.

It maybe the driver has a base emitter leak but I would check R258 and D92, R258 should be 2R2 or for people in the USA 2.2 ohms.

If R258 has gone hi also change C264 and C292.

I have seen R258 go up to 70 plus ohms.

Rick

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. ------------------------------------------------------------------------...

Rick

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.

Rick

Bob,
The crystal in your radio should be just fine.
It should be a 10.24000 MHz, term I used 10.240 MHz in my last is just a general term for the 10.24000 MHz xtal.

Rick

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...

Rick

If the radio is between S/N T70500000 and T70502000, change the 10.240 MHz crystal X1 and realign the PLL section.

On some radios, you may get away with just re-soldering the crystal, but it is best to just replace the crystal.

Rick

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 pl...

Rick

The PC-547 board is the sample, hold controller, and channel 9 squelch gate, which is part of the scanning system, it is not the main squelch, and the main squelch is on the main PCB. If you have adjust the per-sets on the PC-547 board you will upset the main squelch control, you will need to realig...

Rick

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

Rick

Ok then do you have a email ad.

Rick

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

Rick

Try doing the test in this thred.

Rick

Check to see how much current the PA stage is drawing, if low I would change the finals.

You could try unhooking the collectors of the finals and checking the current to see which final is low.

I have had the driver go low, but in most cases it is the finals.

Rick

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%

Rick

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 a...

Rick

The SS3000 is known to suffer with bad soldering.

Rick

You need the right test gear to do the job right.

RF signal generator (100 MHz).
RF power meter and dummy load
A standalone frequency counter (at less 6 digit).
10 to 1 probe
SINAD meter.

There are no short cutes

Rick

Kyle aka Pioneer621, I think you misunderstand me, I already know the answer to the fault, and it was just posted for a bit of fun. I have found some good faults with the President Lincoln and the HR2510 over the years. I have a quit a few more to post when I get my notes sorted out, some are real m...

Rick

Timrim, C130 is ok, this question had already been asked. Q124 is ok, this question had already been asked. ------------------------------------------------------------------------------------- Euhara, PA jack is ok. -----------------------------------------------------------------------------------...

Rick

If your radio is fitted with the X2 crystal of 14.010 MHz then replace crystal X2 with 15.360 MHz.

You will need to do a full realignment on the radio.

Rick

Pioneer621, IC104: RX mode PIN-1 = 2.85vdc PIN-6 = 2.10vdc PIN-7 = 2.10vdc PIN-9 = 2.85vdc IC104: TX mode PIN-1 = 2.85vdc PIN-6 = 1.95vdc PIN-7 = 0.92vdc PIN-9 = 2.85vdc --------------------------------------------------------------------------------------------------- Timrim, L111 has not been adju...

Rick

Timrim, Q135 is ok. Check R168 and R169 and C135 all ok. -------------------------------------------------------------------------------------------------- Pioneer621, IC104: RX mode PIN 8 = 1.4vdc IC104: TX mode PIN 8 = 1.6vdc D147 is ok. ------------------------------------------------------------...

Rick

Pioneer621, Q125: RX Mode B = 8.00vdc C = 0.25vdc C130 is ok. Q125 is ok. Q136: RX mode E = 0.00vdc B = 0.05vdc C = 8.00vdc Q136: TX mode E = 0.00vdc B = 0.04vdc C = 8.00vdc ------------------------------------------------------------------------------------- Timrim, There is a very weak signal at t...

Rick

Timrim,
The signal is good at Pin 9 of the Mixer (IC106) and is 300mw 27.000 MHz, same as what is showing on the display.
The signal at the Base of Q134 is good at 190mw 27.000 MHz.
The frequency changes when you rotate the VFO knob.

Rick

Smokinjoe
I think you should re-read the answers as I think you have missed something.

Zodiac
There is on current being drawn.

Rick

Smokinjoe, There are volts at the Collectors of driver, and the final, and there are correct at 13.8vdc. Pre-amp which one is that? -------------------------------------------------------------------------------------------- Timrim, There is no RF signal at Q124. Check pin 5 of IC103 with an oscillo...

Rick

You have a PM.

Rick

As I did not get the right response from you, I cannot help you with this fault anymore. I assume this is now closed.

Rick

Radio: President Lincoln & Uniden HR2510. PCB Number: PB-111 Condition: Stock Radio only modification 11-meter conversion. Symptoms: No TX power. What is working: The Driver and Final are ok. The Display show TX with key-up. The CPU/MCU board is working ok. All voltage regulators are ok. Skill L...

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