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AM/FM transmitter circuit The first local oscillator frequency (37MHz band) and 10.695MHz frequency generated in the Q12 are led to the Pin #4 and Pin #1 of IC3, respectively, and mixed with each other, resulting in 27MHz band transmit frequency . The 27MHz output is led to the Q8, Q9, and Q10...

AM/FM receiver circuit A received signal passes T7 , then amplified in Q2O, and again passes the band pass filter consisting of T8 and T9, then, enters into the Mixer stage of Q22. On the other hand the first Rx local signal frequency is applied to the base of Q22 through a coupling capacitor of...

Fundamental theory of PLL circuit The word PLL is an abbreciation of the "Phase Locked Loop" in which a given signal is processed to track the frequency and phase of a reference signal. In other word, the PLL is of an automatic frequency control loop or automatic phase control. The PLL circuit...

The PTBM048A0X board was used in a wide range of CB radios from various brands, including: Colt: 480, 485DX, 890, 1000, 1200 (Excalibur) Hy-Gain: 2705 (V), 2720, 2785, 3108 (VIII) Lafayette:SSB80, SSB120, SSB140 (Telsat series) Midland: 77-002, 78-976, 79-892 Cobra: Though often...

In the last 6 months I have repaired over 100 units and built several solid state amps while I could possible do more I choose not to I takes up lots of time. Going forward I plan to do a lot more but it will be a few weeks out as I have a lot of my own equipment I took in trade for partial...

Actually this is one of the easy ones to do, That being said i'm going from memory from working on thousands of radios over the years but here it goes. there is a diode D75 I do believe it needs to be removed then you need to find the wire to the fine control on the clarifier "VoiceLock" that...

I thought I did send you a message I must have screwed it up somehow.

Still there have not heard from you in over a week, Just wondering.

People on Facebook? Ok that speaks volumes to your attitude. But just to show you no hard feelings don't use your little bag of trimmer "pots" be sure they are trimmer "Caps" there is a big difference.

Funny you mention the upc1156H I just received 2 of those in the mail as I have a Robyn 510D mobile that oddly enough was given to me 5 years ago the man said he didn't even get to use it as he hooked it up backwards so to speak it looks like a brand new radio but I put it on the shelf and...

Well if you can actually read schematics that should also mean you can tell the difference between "RECEIVE" circuits, PLL circuits, Transmitter circuits, VCO circuits, AGC circuits, Mic Preamp circuits, Receive mixer stages, Transmit mixer stages, Audio amp stages and of course "BALANCED"...

If the ribbon cable is with it that is fine as well. Let me know what you need for it and shipping and I will get it to you. Oh I assume it worked you just replaced it with something else.

If this is what you have I'm interested.

Thought I would ask you never know. I brought back from the dead a PRESIDENT WASHINGTON it tested my patience and forced me to get back to what I used to teach with respect to the proper approach to trouble shooting, anyway. After fixing all the problems it become obvious the channel selector...

Like Nomad I try not to work on radios anymore that I know it will be a real problem to find parts for, That being said I think if you still have the original meter you may be able to find that type meter in another radio and you can remove the face behind the needle and place it another meter I...

Wow have not done this for a bit. The below list is partial but all have been repaired in the last several weeks and have an old galaxy base on the bench right now. SBE LAND COMMAND LCBS-8 COBRA 142 GTL FOR A MAN IN OREGON COBRA 2000 GTL COBRA 148 GTL (X) 4 1 PILL MOBILE AMP 2 PILL MOBILE AMP...

The 45 watts is most likely the Power Supply rating not the RF.

With my credentials that I will not go into you would think I would be able to find all problems in a matter of minutes but NO! that isn't the way it works. I have been guilty of jumping to the end of line only to say Ok Dennis this isn't working so do like you taught it in Tech School and that...