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

Rick

Stay away from the S45 as you can get a bad one, I have sorted lots of them out, but it can be a costly job. Most Ranger radios (VR 9000 and SS158EDX) have some frequency drift, but this is not a problem once the radio is up to working temperature. It can be sorted out by a good tech. I have used th...

Rick

Scott,
I have probably have a new one. I will have a look one day in the week.

Rick

You do not give the model and PCB number, see www.radiomods.co.nz/forum/viewtopic.php?t=312

The low TX power is most likely a bad driver.
No RX audio is most likely the audio IC.

Rick

Check the AGC, while going from about 0.5uV to about 20uV. You can check it at Pin 14 of IC2 also check the AGC at D12.
One fault I have come across is filter FT6 being bad but only in AM.

Rick

It sounds like the radio has been connect up the wrong way round, so it would be best to check the reverse polarity diode D55 at the rear of the radio where the power cables come in, you may find that it is open circuit in which case replace it with a 1N4003. It is most likely that the audio chip (I...

Rick

2SC1419 is an NPN and not a PNP, and yes you can use a TIP31A which 45 volt at 3 amp.

Rick

TR41 it should be isolated from the heat sink. The voltages you have given are about right, but the Collector is a bit low it should be at supply voltage of 13.8 in RX and should drop to about 13.10 in TX. When the fault occurs, check the voltage at Pin 5 of IC5 TX Mixer chip and the voltage at the ...

Rick

Is the fault the same on all modes?
What is the voltage on the Emitter of TR903 in AM mode TX?
What is the voltage on the Base of TR901 and 902 in AM mode TX?
What is the voltage on the Collector of TR901 and 902 in AM mode TX?
Be carefully not to slip with your test probes or may blow the 2SC2290 up.

Rick

What is the voltage on the Base, Collector, and Emitter of TR41 in AM mode TX.

Rick

It probably is not the swing kit which causing the fault but stock radios is easier to find the fault.

Check all the soldering joints as it sounds that what the problem is.

Rick

It looks like you have lost the volts at Pin 8, it should be about 8 to 8.50 vdc. Check each side of R156, if the volts are ok on the hot side of the R then its likely that C138 is short or IC16 is bad. Also look out for cold solder joints. The voltage at IC16 should be: All readings in TX Mode Pin ...

Rick

Take out the swing kit and put the radio back to stock.
Then check radio and if the fault has gone away it must be the swing kit.

Rick

Have you check the radio for TX audio on SSB? What voltages do you have on Pins 1, 2, 3, and 8 in TX? An all too common fault over look is C141 (.22uF). You can check in you have any Mic audio up to the Mic Op-Amp IC16 with an old ear bud. Just cut the plug of the end and strip the wire back. Then c...

Rick

If VR15 is a bit jumpy. Check C10 (4u7), or try spraying VR15 with some switch cleaner or just replace VR15.

Rick

I did tell you without the right test gear it not easy. It looks like you have something loading the final, bad cap, short on a coil, diode, and resistor. The components may look all right (E.G not burnt) but some components fail and show no outward signs of failing. Of course, you could have blown ...

Rick

Check than the driver bias is right.
Components known to go faulty C265, C292, D93, R254, R258, R304, and R305.
I have had D90 or was it D91 which gave bad audio on SSB, when the component was tested it tested ok but was faulty.

Rick

You could email Cobra and they may help, but do not exept high quality sch. I did a sch for classic 20 LTD which may help you but has none of the bells and whistles. The diagram is on CBTricks http://www.cbtricks.com/radios/cobra/29ltd_29ltd_st_29wx_st/graphics/cobra_29_ltd_classic_sch.pdf You may f...

Rick

I do not have a sch diagram for this radio? as it will help you find faults.

Rick

The PCB number is right at the front the radio and will start with EPT2950??? As for warbling audio on SSB this can be due to a few thinks, like bad driver and finals check they are the right ones as someone may have change them for the wrong ones, also check the bias on the driver is setup right. I...

Rick

When you start a new fault, it is always best to start a new post, as this will help others in the future with the same fault. Q38 TX switch, is PNP transistors, so to get it to turn you need to make the Base negative with respect to the Emitter voltage, this is done by the Zener diode D73 and R220...

Rick

I would try a second radio from your 20 just to make sure its not your setup.
As from what you say about your SWR and power it seams OK.
It could be the mic maybe worth try a second mic just in case it is the mic.

Rick

Do all test with the radio switch off and the powre plug removed. What is the resistance between Top Pin 1 of J118 (Red wire) and ground with let me have the reading. What is the resistance between Centre pin 2 of J118 (Brown wire) and ground with clarifier control fully CW and CCW, let me have the ...

Rick

You need to do some fault finding for you self, you cannot expect us to know all the components which may have failed. When you us a sub device like the 2SC1969 any think can happen. I would start by check the input and output of each transistor in the PA stage with a scope or RF probe, or you could...

Rick

To Scott I am sorry if this post is not inline with the forum, if not please remove it. This is a problem I cannot give a straight answer too. There are some known problems with the new 2950DX Mosfet (EPT695015Z) PCB. I am only able to offer to repairs to the radio at this time. It may look like I a...

Rick

What is the SWR on channel 20?
What is the dead key output power on a power meter with a dummy load.

Rick

You may have lost the ground side of the clarifier control, which is formed by R198. The wiring should be like so: Clarifier control Pin 1 is Red and is connected to J118 Pin 1. Clarifier control Pin 2 is Brown and is connected to J118 Pin 2. Clarifier control Pin 3 is Black and is connected to J118...

Rick

If is the problem is the same in SSB mode, try replacing C84, C85 and C121.

Rick

Try the dealers below.

www.kenselectronics.com/lists/relays.htm
www.westgateparts.com
www.unicornelectronics.com/index.htm
www.digikey.com

Rick

A good 90% of microphones on the market today use a standard colour (Color) code, which has been in use for about the past ten years. Screen (Shield) = Common Ground. White = Audio. Red = TX. Black = RX. For a Cobra radio using a four-pin type plug. 1 = Screen (Shield). 2 = White. 3 = Red. 4 = Black...

Rick

Check the voltage on Pin 6 of the PLL on channel 1? Check the voltage on Pin 6 of the PLL on channel 40? Check the voltage on Pin 17 of the PLL on channel 1? Check the voltage on Pin 17 of the PLL on channel 40? Do you have a 6 digit frequency counter. If you do check the frequency on Pin 1 of the M...

Rick

What is the voltage on Pin 9 of the PLL when you go from channel 1 to channel 40?

Rick

Check for cold solder joints around the loop mixer, also check the voltage on Pin 8 of IC10.

Rick

When you use a 2SC1969 as a Final in the Lincoln, it can be unstable and can self oscillate and be very un-linear due to the lack of feedback, which will destroy the 2SC1969 and may cause other damage. You can cure the problem by using some R/C feedback network components. Solder one leg of a .0047u...

Rick

The easy way to find out what as gone on is un-solder the driver and final and test them.

As for setup, use the alignment data, that what it's for.

What is "bios"??. " I this my PC one of them lol.

Rick

You probably have a bad trace from the TR51 to TR41.This trace runs in the side of the board. Unit 67 The track from TR41 does not come from TR51, as TR51 always has volts on its Emitter is because it direct connected to the power socket. The volt for TR41 comes from the On/Off switch. If the volts...

Rick

Complete front panel chrome bezel with faceplate for Galaxy DX88HL, and heatsink fan for Galaxy DX93T.

Rick

You maybe doing the test right but it is strange that you have no volts at TR41. It looks like you are maybe not using your meter correctly. With your negative (Black) meter probe connect it to (power ground) and not the chassis the black negative wire coming from you power supply is the best one to...

Rick

This one will do the job, I have been using the SVC251 for over 9 years in all sorts of radios from Ham and CB.
SVC251
FC54M
KDV251
BB809
BB909B

Rick (Euro Radio Co).

Rick

Dennis, the SS3900 is a radio with history of frequency drift problems and with your method, you will just chase you tail. It is best just let someone with a good knowledge of the type of chassis set it up. Since SS3900 first can on the seen, I must have converted and serviced well over 800 of them ...

Rick

If you check my Sch diagram on CBTricks you should be able to work out where the wiring should go.
http://www.cbtricks.com/radios/rci/rci_ ... 50_sch.pdf
http://www.cbtricks.com/radios/rci/rci_ ... wiring.gif
Hope this helps, let us know how you get on.

Rick

Sorry my error. I need to go to Specsavers lol. This is happens when you get as old as I am.

I read it as TS520 opps.
I do not know of any problems with the TS850, but will have a look in my Kenwood fault finding guide.

Rick

Gee thanks, my head is getting bigger by the minute lol.

Rick

The Pearce-Simpson Super Panther was never a popular radio, therefore Sch diagrams are hard to come by, this is most likely why you are not getting a answer. They are two version of the Super Panther Mk1 and MK2 I think its only the MK2 which has the label MK2. If the PCB is the PTBM048ACOX or the P...

Rick

The spec Sensitivity 0.25uV for S/N 10dB Selectivity SSB 2.5KHz for -6dB 4.2KHz for – 60dB Image Ratio and IF Rejection Better than 50dB One fault I have had with low RX performance is mixer Q9, I could not fine any of the voltages to be wrong, but on replacing Q9 and all was will again. It maybe wo...

Rick

If it off frequency in TX try adjusting VR801.

Rick

The original TS-2000-DX do not have a PA function.
That why I went down the route I did.

Rick

People like to play, it keep some of us in work.

Rick

You do not need to use the Quote.

Check from Pin 2 on the Mic socket back to Pin 3 White with Screen cable of J110, J110 Pin3 is link to Pin 1 on J112 which go to one side of the Mic Gain control and centre from the Mic Gain control back to the Red wire on Pin 2 of J112.
Hope this helps.

Rick

It is not just a simple case of using a pot as the dimmer control. I do not know which Galaxy diagram you look at but none just use a pot to the 5 volt supply as there is no 5 volt supply in any case. The dimmer control is used in conjunction with a NPN transistor Q403 that has a limit resistor in t...

Rick

Do you have a TX carrier on AM and FM mode?
Is it just case of no TX audio on any mode.
Also please read the info on the link below
www.radiomods.co.nz/forum/viewtopic.php?t=312

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