RCI 2995DXHP low power no receive

[Crambone]

RCI-2995DXHP

No receive on all modes & when connected to load on USB Signal Meter goes to S9, LSB S3, CW S4. AM FM & PA S0
Unit is only putting out dead key 2.5w and 28w modulated on AM, USB & LSB 26w modulated. That’s with amp in line, when I pull the J22 amp key I’m seeing 0.3w dead key and 3.5w modulated.

Also I notice that the 8 strip test connection on the board has a SQ and I’m seeing 5.55 - 5.65vdc when squelch at 0 to 10
J25 S1 shows 1.5-2.5vdc & S2 shows 0 - 2.5vdc

Any suggestions for troubleshooting?



Drew

 

[BayouRadioAmplifier]

No replies yet? your descriptions go all over the place.

I had fun working on one of these over a year ago.
found trouble in the modulator (replaced Q67).
Then I played around on the 10-meter repeaters
up in New York state and Toronto for days
from down here.

is your main board a 011 or 015 version? MOSFET or
bipolar transistor RF on that board? there are errors
in the drawing of the MOSFET version around the
relay on the external RF amp. with no receive,
sounds like a problem with that relay circuit. ??

start with the TX on the main board.

pull off J22 for no external RF amp.
Key up in SSB mode. measure the voltage
at shorting board for T.P. 7/8/9
for around 12 volts.
then key up in AM mode
and turn the RF Power control back and fourth
to see if it varies around 2 to 8 volts.

 

[BayouRadioAmplifier]

OIC / oic / oh I see you have a previous post
on this radio. ? ? sounds like there is
a problem with the external RF amp.

 

[Crambone]

OIC / oic / oh I see you have a previous post
on this radio. ? ? sounds like there is
a problem with the external RF amp.

It is a 15 board, I’m not sure it’s the amp because it has no receiver.
I put a meter onTP 7,8,9 and in SSB I’m seeing 11.7 - 12.8vdc
On AM I’m seeing 3.75 - 7.65dcv
Thanks for your help
Yes I may have had an old thread but was away for 4 months and thought it may be better to start clean.

Drew

 

[BayouRadioAmplifier]

looks like your modulation circuit is working.
and you get a few watts of carrier output
when with J22 unplugged you said.


I would look into the 8 V switching T/R circuitry.
maybe the 8 V for receive is bad.

 

[Crambone]

looks like your modulation circuit is working.
and you get a few watts of carrier output
when with J22 unplugged you said.


I would look into the 8 V switching T/R circuitry.
maybe the 8 V for receive is bad.

Ya I’m getting modulation and some power out. Any help trying to follow the 8v switching T/R circuit that you might be able to tell me? Known test points to look at?

Drew

 

[BayouRadioAmplifier]

so when in FM mode, squelch off, volume up, do you
get the usual receiver noise? the rush sound.?

and in SSB mode receive, all that usual noise, as a
radio with no antenna connected to it..??

 

[nomadradio]

Do you have a frequency counter you can put in line or patch into the 'counter' jack on the rear panel? Makes me wonder what frequency is coming out of it when you transmit. If it's the same as the display shows, you'll hear it in another radio in the room. Probably simpler than plugging a counter into the radio to read the AM carrier frequency.

If it's not on the frequency the display says it is, that would be the very-first diagnostic point to discover.

73

 

[Crambone]

so when in FM mode, squelch off, volume up, do you
get the usual receiver noise? the rush sound.?

and in SSB mode receive, all that usual noise, as a
radio with no antenna connected to it..??

No noise at all with no antenna, volume 100% and rf gain 100% in all modes

 

[Crambone]

Do you have a frequency counter you can put in line or patch into the 'counter' jack on the rear panel? Makes me wonder what frequency is coming out of it when you transmit. If it's the same as the display shows, you'll hear it in another radio in the room. Probably simpler than plugging a counter into the radio to read the AM carrier frequency.

If it's not on the frequency the display says it is, that would be the very-first diagnostic point to discover.

73

Just checked both was with another radio as receiver and with frequency counter. Sounds great in AM not perfect in LSB or USB but not bad in any stretch.
Frequency is spot on in AM on counter.

 

[BayouRadioAmplifier]

so no noise out of the speaker?
of any kind?

maybe a problem in the speaker switching circuit,
the external speaker jack. /

 

[Crambone]

so no noise out of the speaker?
of any kind?

maybe a problem in the speaker switching circuit,
the external speaker jack. /

Ya nothing at all I checked to make sure external speaker jack wasn’t bad and it’s good. No sound at all or movement on meter when I inject a 1kHz 0db signal on any frequency I’ve tried a few.

 

[Crambone]

Ya nothing at all I checked to make sure external speaker jack wasn’t bad and it’s good. No sound at all or movement on meter when I inject a 1kHz 0db signal on any frequency I’ve tried a few.

What controls the squelch power? I don’t get any fluctuation in voltage when I go from 0 squelch to full squelch. It’s like the squelch is on full all the time.

 

[nomadradio]

or movement on meter

Time to try the manual analog digital signal injector.

Lay one finger (digit) alongside the shaft of a small screwdriver. Find the black plastic 455 kHz AM IF filter. Probe the tip of the shaft to the foil pad for its input, and then the output. You should get raucous noises. They should be louder on the output pin than the input pin.

If it passes this test, find FL2, the small 10.7 MHz crystal filter. It either looks like a metal quartz crystal, or like a small brown blob of ceramic. This filter is in line with the signal path for both AM and SSB . It has three leads. The center one is ground. Probe the two outside foil pads, and you should get raucous noise on the output pin and a lot less on the input-side pin.

Selecting either sideband mode and trying the same test on FL3, the bigger metal-can crystal filter should also get you noises, louder on the input foil trace than the output trace.

If it flunks any or all of these tests, you can focus on what's downstream from the injection point where it flunked.

If it passes all three of these tests, the problem is upstream of FL2. Leaves more than a few possible suspects, but knowing whether to look upstream from the three filters, or downstream is a good place to start.

73