Need alignment,frequencies points?

[work in progress]

Can I get some help here,my son had some fun when I walked away for a moment. He thought it was funny to play turn the cores,on these pots.
I posted pictures,can someone give me the low down on how to repair adjust the pots,and where are my frequency check points,as I can align this with minimal equipment, but have it all,,what I would need. I am in need of some major assistance, Thank you all. Here is the radio he turned the pots on.

 

[ForestRunner98]

Wow...just turning any pot willy nilly? You’re going to need quite a bit of equipment if all the pots were messed with. Oscilloscope, spectrum analyzer, frequency meter, tone generator....not say you can’t do it but I would just have it done by a qualified tech. Just my $.02

 

[Shadetree Mechanic]

Welcome! With minimal equipment, I have heard of tuning one radio to another. With everything adjusted, it may be hard to know what to do first. The alignment info should be on cbtricks.com and would be a good place to start. I am sure someone that knows this radio will be by soon.
Chris

 

[nomadradio]

The drawback of published alignment procedures is that they assume you have a working radio, receive and transmit.

Don't remember ever seeing anyone publish a "from the grave" procedure.

I would start with the PLL. Turning a couple of tuning slugs randomly will cause it to lose its grip (lock) on the selected channel frequency. When this happens, most radios will totally shut down. FCC rules require the transmitter to shut down any time it could accidentally transmit on a frequency that's not a legal CB channel. Some radios shut down the receiver audio as well. Can't remember right offhand if the Cobra 29 Night Watch radio does both.

Trouble is, the only way I know to get a PLL circuit back to proper behavior is with an oscilloscope. Might as well be a swiss-army knife for working with PLL circuits. Never learned any other way. A meter alone just doesn't tell me enough.

If the green receive LED on the front fails to turn red when you key the mike, the radio's PLL channel synthesizer is the first target to fix. The entire rest of what the radio can do depends on that circuit.

73

 

[work in progress]

The drawback of published alignment procedures is that they assume you have a working radio, receive and transmit.

Don't remember ever seeing anyone publish a "from the grave" procedure.

I would start with the PLL. Turning a couple of tuning slugs randomly will cause it to lose its grip (lock) on the selected channel frequency. When this happens, most radios will totally shut down. FCC rules require the transmitter to shut down any time it could accidentally transmit on a frequency that's not a legal CB channel. Some radios shut down the receiver audio as well. Can't remember right offhand if the Cobra 29 Night Watch radio does both.

Trouble is, the only way I know to get a PLL circuit back to proper behavior is with an oscilloscope. Might as well be a swiss-army knife for working with PLL circuits. Never learned any other way. A meter alone just doesn't tell me enough.

If the green receive LED on the front fails to turn red when you key the mike, the radio's PLL channel synthesizer is the first target to fix. The entire rest of what the radio can do depends on that circuit.

73

Thank you,I did find a alignment book,manual,I figured I should look around. Jumped to fast,I appreciate your time.

 

[work in progress]

Hey, the alignment manual ain't worth a ,99 cent bar of soap,I really need a ALIGNMENT procedure. I am screwed silly without the procedure,I have a Oscilloscope,Freq counter,and borrowed a Rigol Function,Arbitrary Generator,I believe I can go for it now. Can I get a alignment procedure from someone. Thanks, I am really in a bind. What to do with the kids, should make him learn how to undo his game with the pots,make him FIX THIS. I am mad,but I left the radio out,with the cover off,and tuning tools next to it. It is my fault. Any info is needed,I thank youfor info

 

[Handy Andy]

WOOF - to See a Cobra 29 Belly up on a table!

Well, what have I got left in my graphical bins...

(**Rattle - Rattle - sounds of Rummaging and Mouse Clicks...**)

Hmm...haven't seen this in a while...

Would this help?

​

 

[work in progress]

Yep,this is partly what,I have,Thanks,I need also where do I check the frequencies I am setting? I have a small Freq counter that is almost on frequency,maybe a few Kilohertz off,nothing major. What do I hook to to get the different stages or frequency. 455, 10.240, 10.695, 27,185 ( TX ),18.??! ( RX )where are these hook ups. I can somewhat read a schematic,I can find my way around. With this and the check points,I may be able to get her back. I will wait for frequency points before I attempt this. Talk soon.

 

[guitar_199]

This is genuinely not being put here to "push buttons".....but.....

a few kilohertz off? It is only 10 Khz to the next channel and half of that BELONGS to the next channel. If there is any way you could calibrate yours....even if it is just by comparison with someone else's and setting yours to match. Your experience would be a lot better!!!

Best of luck!
Bob

.......I have a small Freq counter that is almost on frequency,maybe a few Kilohertz off,nothing major. .....

 

[Handy Andy]

Yep,this is partly what,I have,Thanks,I need also where do I check the frequencies I am setting? I have a small Freq counter that is almost on frequency,maybe a few Kilohertz off,nothing major. What do I hook to to get the different stages or frequency. 455, 10.240, 10.695, 27,185 ( TX ),18.??! ( RX )where are these hook ups. I can somewhat read a schematic,I can find my way around. With this and the check points,I may be able to get her back. I will wait for frequency points before I attempt this. Talk soon.

Oh, so you're looking at doing this for them...

Best to stop and check with you on what you actually have to work with.

IF you have a FC-3XX - counter from "Galaxy" or perhaps a Palomar or some other off-brand in a little box with brilliant colored light that giving you numbers it thinks you should know...well, can we get closer to something that you DONT have to connect to the Antenna Connector, Key up equipment and see something like this?

(Why are my initials up there?)
​

Anyways, need to know What you have so we can then guide you...

Meanwhile I'll grab some of your shots and see if the patient is Focused enough to stay as a working model and not have to substitute in another Crash Test Dummy as a Stunt Double...

There's Union reps and laws that may come up ....

 

[work in progress]

Bob,all I have to do is throw it on th Sigi

This is genuinely not being put here to "push buttons".....but.....

a few kilohertz off? It is only 10 Khz to the next channel and half of that BELONGS to the next channel. If there is any way you could calibrate yours....even if it is just by comparison with someone else's and setting yours to match. Your experience would be a lot better!!!

Best of luck!
Bob, it's not that bad,I just have to throw the Freq Counter on the Signal Gen,throw a Freq at it,and align the Freq Counter. The person I got it from,tells me must align the counter every time he uses it,it losses freq when sitting and cooling down. This counter has to warm up for a 1/2 hour before use. I made that comment about the Counter seeing if someone is on their toes,looks like Bob is up to part this afternoon. Thanks their Bob.

 

[work in progress]

I have enough equipment to do the job,I have a $99.00 Signal Gen,25W 50 ohm Dummy Load on a SWR- Watt meter,I also borrowed 100 MHz Oscilloscope,one of those digital ones with a carry handle on it. I believe I have the tools to get me there. I started with the 3.20 Voltage fromm the VCO? I set the Generator to 27.205, on channel 20,Mod. 1000 kHz at 30% AM Depth,and adjusted the Gen to 2 Volts for receive alignment. I am going to peak the 2,3,4,5,6,7,8,and L9 coils. I shall do the receive,but may need help on the TX part. Thanks gentleman.

 

[Handy Andy]

Well-equipped!
But study the "big graphic" it has the Test Points and the steps to help you get TX working

Ok? Back later today as some home stuff has to get finished up first...

Happy Wife = Happy Life...

 

[Handy Andy]

While I work on the home project...

Wanted you to go over YOUR work and fix that wax mess, we have to find Test Points in all of that...

​

Best to REMOVE some of the wax - just dig out components carefully and gently pry / lift / pull away wax so you can get access, for you will need to possibly Scope L22 if you can't get any RX noise to start this.

I didn't see one on your NW but if you have one, or muddeled (a Modification) in this one Be sure to Center your DELTA TUNE Knob Before you start this whole process.

Delta Tune is on SOME Cobra 29's but in the NW the DIMMER knob replaces it and there is no provision for it NORMALLY on the Night Watch - I've seen worse...

Why ask? Because when a radio doesn't have any RX or TX or both, there may be a botched mod in the Delta Tune area - killing power to the PLL - you have lights siren and all the stuff of radio - but no heartbeat because they killed the L23 (10.240 Crystal) section by trying to mod in a slider or some other similar concept.

 

[work in progress]

Done done and done, dug it all out. Used a hot mini screwdriver. Take a butane mini torch and heat the end of the mini screwdriver, ( with the radio unplugged ) then when you think it is hot enough,run it through the wax. The hot screwdriver melts the wax,but sometimes it comes back when it cools. But there won't be much left as it all melted.. This is the way I clean the wax,ready to "Rumble". Pro wrestler.