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The problem with fixing radios...

brandon7861

Loose Wire
Nov 28, 2018
1,107
1,202
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is that your friends buy "untested" stuff on the internet and assume you can fix it for them.

This one is a Royce 621. It doesn't transmit, and the garbled up stuff it does receive comes in exactly the same on every channel. There are the wrong capacitors electrical taped in place in the power supply, solder blobs and flux all over the board, and various other parts obviously messed with. At least the meter light works. My friends are getting charged an hourly rate from now on lol.
 

is that your friends buy "untested" stuff on the internet and assume you can fix it for them.

This one is a Royce 621. It doesn't transmit, and the garbled up stuff it does receive comes in exactly the same on every channel. There are the wrong capacitors electrical taped in place in the power supply, solder blobs and flux all over the board, and various other parts obviously messed with. At least the meter light works. My friends are getting charged an hourly rate from now on lol.
What is the hourly rate for necromancy these days?
 
What is the hourly rate for necromancy these days?
Havent decided yet, but it seems like a sought after skill.

If its a Royce, toss it in the dumpster. Junk crap that nobody wants to fix....
I want to. It is a good learning experience.

This is where I am at:

The PLL has it's VCO topping out at 38.5MHz, nothing coming out of the TX test pin, and the LD pin is high suggesting out of lock (which makes sense looking at the VCO frequency).

This is what I believe is supposed to happen....

There are three crystal oscillators in the sardine can. 10.24MHz, 10.695MHz and 36.19MHz. The 10.24MHz crystal goes through a /1024 to make 10kHz for the phase detector during RX and TX. The 36.19MHz signal mixes with the VCO signal (at 37.66-38.1MHz) to create 1.47-1.9MHz for the programmable divider (N=147-191) to make the other 10kHz signal for the PD on both RX and TX. The 10.695Mz signal is mixed with the VCO signal during TX to create the output frequency.

Right now, I have 38.5MHz coming out of the VCO, and nothing coming out of the TX pin. What I do not understand (lacking a schematic) is if the 36.19MHz oscillator and the 10.695MHz oscillator are both dead (scope says so), or if the LD pin is keeping the 10.695MHz oscillator turned off. It uses the M58473P, and I believe those were programmed at the factory for the strange divide by N numbers (they even rearranged the binary input pins at the PLL programmable input pins with respect to the channel selector so it isn't as easy to attack with a switch forcing people to swap mixing crystals instead, dirty rascals lol) and I bet they are very hard to find. I am hoping it is just a dead 36.19MHz crystal.

Looks like I might be taking the sardine can out and drawing a schematic for it. Was hoping to avoid that, but I think many people out there want a schematic for that too. Also, there is a 200Ω variable in the PLL that was maxed out and I have no clue where it should be set without a schematic to offer a hint.
 
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It never fails, when I am out in the garage, neighbors stop by to see if I can look at their mower, weed eater etc. Guy down the street stopped by and asked me if I can put a transmission in his car......

I have been fixing things since I was old enough to break things. I fix broke junk for a living. (Ok not really junk) Then I come home and fix more junk. I am all junked out and working on cars is not as fun as it used to be. I am starting to work on radios, but for now, just my own junk.

I would much rather talk to you guys on the DX!
 
It never fails, when I am out in the garage, neighbors stop by to see if I can look at their mower, weed eater etc. Guy down the street stopped by and asked me if I can put a transmission in his car......

I have been fixing things since I was old enough to break things. I fix broke junk for a living. (Ok not really junk) Then I come home and fix more junk. I am all junked out and working on cars is not as fun as it used to be. I am starting to work on radios, but for now, just my own junk.

I would much rather talk to you guys on the DX!


I hear ya. I did commercial broadcast equipment repair and installation for 22 years. Basically a one man army for the last 5 years or so that I was in the business. I got burnt out. Changed careers and put the soldering iron away so to speak. I still have people ask me from time to time if I would look at this or that. I always reply that I have neither time nor space to do so and even if I did I have no desire. I still work on my own stuff but that is it.
 

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