Broken RCI 2990dx

[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 anyone willing to lend some guidance and advice on this 2990dx radio?

Someone or something did some damage to this rig. I bought it
this way. Board number is EPT695011A.

Besides the regulator Q51 being shot and the 7.5 volt Zener D68
missing, and now have been replaced.

The CPU display lites up but nothing shows in the screen.
A short trace going to the positive side of C306 was
burned open on the component side so I fixed that.
The TX led stays lit in RX and goes off when I unplug J10.

Q66 and Q67 were history, D67 was missing so I replaced those plus
the TA7222 chip.
I replaced all the electrolytic caps around the audio amp and TA7222
audio chip side of the board with higher voltage ones.
Replaced Q48 and Q49 and D65.
For all I know it could have been struck by lightning.

I stuck an old style CPU in and it fired up, of course I know it wont
work that way. Have a new CPU coming.

The PA mode works fine, volume, RF gain, Mike gain, RF power control,
and squelch all function. But the air noise coming through the speaker
has a fast oscillating sound.
I got it to recieve from another radio once by trying to find which frequency it is on.
I have traced the noise to the area around IC2. When I probe TP16 by IC2 and pins
7 and 8 of IC2 the noise gets very quiet.

U2 gets hot right away when CN601 is plugged in the CPU and the audio
noise gets really weak.
The mike will key up the transmitter sign in the old style display,
but the noise from the speaker comes back gradually when unkeyed.
I don't have a good way figured to diagnose this thing.
Wish I had a voltage chart or could have someone tell me where to look for
what voltages.

Please help.

Regards, Euhara

[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 what to check to find this fault?

Regards, Euhara