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For that radio to perform its best, the alignment will be far more effective if the clarifier is modified to control both the transmit (TX) and receive (RX) frequencies simultaneously. In other words, when you adjust the clarifier, it should shift both frequencies together to keep them in sync...

I use a Rigol TS-815-TG spectrum analyzer frequently, and I'm confident you would be very happy with one. It's an incredibly powerful tool for component-level troubleshooting. Once you learn to use it with a probe to directly observe frequencies, you'll find yourself wondering, "How did I ever...

I found this format in my old teaching aids from my golden days at community college, I went ahead and modified it some it may help and i may not but I offered it anyway. If you find mistakes feel free to correct them. I will take a look at the schematic and see what could be the issue with...

I don't use this particular device but I do use a scope for this and sometimes I use a spectrum analyzer depending on what I'm trying accomplish I also have an old Heathkit VTVM that I use with an RF probe and I really like it. So there you go. I have been using these kinds of equipment for...

Ok here is a Word doc. with all that mess in it sorry didn't know I had this I have about 1500 schematics on my new Computer system and still have not had time to look at it all.

OK BELOW IS ALL THE INFO I HAVE SORRY IT'S IN SEVERAL POSTS AS IT WAS TO LONG AND I DIDN'T HAVE TIME TO BREAK IT DOWN IN ONE FILE.

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.