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

euhara

board number ept695015a
sounds like it is in both am and ssb dont remember which trannies do the switching.
also volts don't go up when switched from am to ssb.
any help appreciated.
Thanks Jim.

euhara

Can anyone help with this problem on this 2990dx RCI radio Main board number EPT695011A? Got a new CPU and that helped, now trying to adjust the VCO's at 24.890 Mhz neither L13 or L14 will do anything. Pin 15 of IC2 and TP10 has 5.00 volts and both should be around 2.00 volts. Can anyone tell me wha...

euhara

Radio Make and Model: RCI 2990dx surface mount PCB Number: EPT695011A PLL Number: Test gear available: Scope, freq. counter, DVM, solder station Symptoms: What is working: see below What has been tried: see below Did it suddenly happen ?: Bought this way Anything else that may be of help?: Hello, Is...

euhara

What you are calling the hotmelt pack plugged into CN611 is the echip which gives you 11 meters. Far as your problem goes I have no idea of the cause.
Regards, Jim

euhara

I like to be ignored. Doesn't look like much is happening on this forum.

Thanks anyway,
Jim

euhara

Radio Make and Model: RCI 2990 Old style PCB Number: ept295013z PLL Number: ???? Test gear available: DVM, Frequency counter Symptoms: Onboard SWR test doesn't Reach set point What is working: Everything else works What has been tried: Turned RF power up fully and tried to set calibration, will not ...

euhara

Only other thing I can think of is to check IC19 and C216 and C219, but I am not a tech.

Jim

euhara

Have you checked Q54 the SSB/CW audio switch?

Jim

euhara

Yes the 1ss53 is a proper replacement for the mc301 diode

Jim

euhara

Thanks anyway, I got it fixed

Jim

euhara

Radio Make and Model: RCI 2990 PCB Number: EPT295013z PLL Number: ????? Test gear available: DVM Freq. counter, watt meter, mod meter Solder station Symptoms: Can't get rid of talk back What is working: Everything What has been tried: Checked and tested D78,D100,D47,IC16,IC19,Q41,Q42,Q45,Q52,Q53,Q55...

euhara

If it uses a battery test the battery.

Jim

euhara

Well I think the problem must be in IC2 one of the diodes on there must be kaput.

JIm

euhara

Then R207 must be the fault.

Jim

euhara

I believe your answer will be that you was just joking about the problem

Regards, Jim

euhara

Well then would you test L20 and see if it is keeping its setting properly?
Also Test L19 just for fun.

HOW about FET3 that looks like a good one to test. And don't forget to test L46.
Jim

euhara

Seems we have been all over the PLL area and no luck there in finding the fault.
We have proven some things and disproved others. So would you tell us whether we have been close or need to go another directio, else give us a clue.

Regards, Jim

euhara

How about testing L16 is it the cause of the noise?

Jim

euhara

Have you tested L17 to see if it is working properly and is it?

Jim

euhara

Seems our test giver has disappeared perhaps James and myself angered him complaining about the schematic. LOL

JIm

euhara

OK I will try once more. By the way your schematic is a little worn and I haven't found a better one so I have to look in the radio to find numbers.

Is there any noise on pins 5,8,or10 of IC2?
Would you test Caps. 80,81,90, and 92 for me.
Is there noise on pin 7 of IC3 TX mode?

Jim

euhara

Well then I think this is not as esay as you thought for us. I'm about out of guesses.

Jim

euhara

Have you tried a known good michrophone?

Jim

euhara

Would you test C172, 173, 174, and D63, and D64

Also have you checked for solder bridges on the track side and that all solder joints are ok concerning these?

Is there any noise on pins 1,6,and 8 of IC4?

Regards, Jim

euhara

Are the voltage readings ok at IC6? Have you tested all the electrolytic caps in the audio circuit. Since it is an old radio some of these may be faulty. Perhap I should ask, is the PA working normally and is it noisy?

I'm just guessing as usual but I try.

Regards, Jim

euhara

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

Jim

euhara

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

euhara

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

euhara

All you need is a helicoil to fit from 5/16 to 3/8, you should have them there. They come with a tap and a steel insert in sets. Hope this helps.

Cheers, Jim

euhara

Many thanks Scott,
Success!!

Got the Mike wires on right and thanks to you it is finished and working fine in all modes.

It is a fine looking Radio and will now look good on my shelf for a spare.

Cheers,

euhara

OK Scott, You are correct the audio works fine by shorting those two pins and this radio has been golden screwdrivered and wires chopped up but I have fixed all those except at the mike internal plug (the one in the radio.) Can you help check those out or maybe be sure I have all correct in mike plu...

euhara

OK Scott, By the way thanks for having such a good Forum. It is the most active helpful one I can find. I just discovered that the external socket must not be grounded properly as when I physically ground it the audio comes up full. So there must still be a wire wrong in the mike. Can you straighten...

euhara

Sorry Scott, it is C186 next to TR43 which I replaced. Can you furnish the voltages for TR43 I can't find a reference to that one, also what type is Tr43?? On Rick's schematic which he redrew the Transistor number next to C186 is in fact TR45 and is a 2SC458. Board must be wrong I think. Thanks, Jim

euhara

OK thanks Scott for the fast replies, Replaced C182 and no change. The wire is connected from mike pin 3 to speaker wire in board at rear of radio it is a green wire. But can't find TR45. Is it possible the board is marked wrong? As it should be by C182 but the board is numbered TR43 there although ...

euhara

Thanks Scott,
I have the audio connected to an external speaker, easier to work on that way. Since the PA speaker is so loud i assume everything must be connected. Am I wrong?
So I am thinking it must be some faulty component and will check all you suggest.

regards, Jim

euhara

Hello to the forum, Guess I will look for more help and post my problem, I try to help myself much as I can until I get lost as where to look next. I have a older Cobra 148GTL with low volume in receive mode. Board number PC-412 is all I can see PLL Chip is MB8719 When I got this radio it was dead, ...

euhara

I'm sure Rick will correct me as I am not a tech, but did you test D83?

Perhaps it has something to do with your problem. Anyway I tried to help and hope this does help.Regards, Jim

euhara

There is another setting you need to do to center the transmit and receive to the same frequency, I'm not a tech but I believe VR5 or VR7 centers the frequency, also I believe CT2 needs to be adjusted you can find the alignment procedure at cbtricks.com radio information. So don't take my word for c...

euhara

You might try this for the clicking relay, in the left rear of the radio near the finals is a Tantalum capacitor number C179 it is directly in front of a green Mylar capacitor. Try removing this C179 capacitor and replace with an electrolytic capacitor of the same value, I believe it is a 2.2uF. Tha...

euhara

You might try this for the clicking relay, in the left rear of the radio near the finals is a Tantalum capacitor number C179 it is directly in front of a green Mylar capacitor. Try removing this C179 capacitor and replace with an electrolytic capacitor of the same value, I believe it is a 2.2uF. Tha...

euhara

The battery is on the back side of the display about the size of a computer battery and looks the same. Just below is a good review and history of the 2900. http://www.cqdx11.com/CB-Radio/RANGER/RCI_2950DX/index.html Try this, they say it is a factory service manual, Jim http://www.cbtricks.com/radi...

euhara

I guess I need for you to test D165 for open or short.

OOPS someone already asked that.

So check to see if the PA jack is stuck open just for fun.

Jim

euhara

Sorry I can't tell which is which without looking in the radio, but I suspect the pre driver has no volts because the transmitter is not being turned on. So I will just watch.

This is interesting though and a good idea Rick.

Regards, Jim

euhara

I don't know anything but I think Q124 is the pre driver or is it Q134, and I would have you check the collector of that with the mike keyed for about 8 volts and go from there.

Just thought I would give this a try. Don't be too harsh with me.

Jim

euhara

Simply turn down the mike gain some and the radio will still modulate enough to get out.

Jim

euhara

I agree.

Thanks to all,

Jim

euhara

Thanks to both Timrim and Rick, Rick Here are the voltage readings you asked about TR903 Emitter transmit AM 7 volts Tr901 and 902 both have the same voltage on collector or base in both transmit and receive mode in AM Base 0 volts on both Collector 14 volts on both it now does not transmit at all i...

euhara

Guess ya can't win em all. Thanks anyway guys.

Jim

euhara

Hello everyone I have one more problem with a Ranger 2990. This one has a problem with the little amp at the rear of the radio. Board number EPA010010A This was evidently not working when I got the radio. Now the radio works fine but when keyed with the amp plugged in the output power drops instead ...

euhara

Thanks again Rick,
Don't know how I got 2 identical posts but anyway I replaced all the parts you mentioned and SSB is working ok but think I need to watch VR15 because it is a little nervous and jerky when I adjust it. Must have some bad spots.

Regards, JIm

Search found 62 matches