The Electronics Universe
Electronics Forum => Test Equipment => Topic started by: The Radio Shop on August 08, 2014, 10:25:31 PM
-
https://www.youtube.com/watch?v=HO_nYitbozU&feature=youtu.be
https://youtu.be/HO_nYitbozU (https://youtu.be/HO_nYitbozU)
-
Here the the circuit that is bad.
-
The next 2040 I am going to attempt to fix is in bad shape.
The first issue is the PLL is not operating properly. Very little signal out and it does not change when you select different frequencies.
First thing we will do is check the power supply and verify we have the correct voltages. Since the 74xx chips needs 5 volts to operate we will have to verify that they are spot on and have little ripple.
-
Another 2040 here in the shop has bit the dust. This is the one I repiared the meter error months ago.
It has the deaded PLL unlock symptom. You turn unit on set to generate and the radio under test hears nothing. A few minutes later the radios hears a signal sweeping the band. So the PLL is running wild and is not locked on one frequency.
My weakness in radio has always been the PLL circuit. So I have a lot to learn. There has been others that have helped me through it to understand more about how PLL works. The PLL in these type of generators are a bit different than you ham or cb radio. These unit run a 27 MHz signal at the VCO's output.
The stock service material available for the 2040 is not bad. However they did not give you a block diagram, there are no frequency path on the schematic, and most circuit blocks are not labled what they are. There is a copy of the manual with some of this info available. The stock manual does provide a voltage chart.
So at the momnet I have 3 of these units. My 2040 on the main bench is in pretty good shape and works fine. Now the unit on my other bench has failed. This one is the one I replaced an opamp in and is a very clean and has never been worked on that I can tell. The third unit is one I bought that was non working. Someone had modified it for extended frequency coverage. Has a lot of hack jobs done to it but it is doing the same as the other unit.
So what I am going to do is take my working unit and open it up. Go through it with a volt meter and scope noting readings onto the schematic. In all hope we can find out more of what goes on in these old test gear.
-
The manual listed below is the one that has the circuit lables. It is what I will be using to make the test notes.
I like all that want to join in please do. But lets keep the thread on topic please.
-
What I found today
It has a 10.240 and a 10.243 oscilator.
I figured out say channel 20 you take 27.205 subtract the doubler frequency of 20.48 equals the clock frequency of 6.725.
The VCO runs at 27 meg signal. Have not figured the doubler signal yet.
What I did find on the bad unit is at Q307 there should be 27.205 MHz while on channel 20. But I am getting 24.7526 MHz there.
Also IC304 should have 6.725 MHz on pin 12 and 13. 12 and 13 are tided together. I am getting 8.889 MHz on 12 and 4.279 MHz on 13. Not sure how this is happening unless there is an issue with IC304.
-
schematic
-
schematic
-
Greetings!
Man I'd just hate to have you start dropping in parts, but I've gone over both schematics. The programmable dividers...how many clock cycles to the carry before the "overflow - carry" onto the next divider? I see Pin 11 looks to be the reset so the pulse train starts back at zero back at IC305.
Something I really do not want to do with this old thing. The way you have to lift the board out to get under it can cause lots of problems. The board is double sided with plated feed throughs which opens another can of worms. A lot of care had to be taken not to damage things.
Now, if the PLL is going on out lock, how is the health of Q304 and Q307 - now I do see the Varactor on Q307 as well as several electrolytic caps - it's why I'm asking about their health. I'm under the belief that if both Xtals - going through the phase detector and the separate frequency divider - if they don't match then the unit is sensing this and shutting down.
I scoped both Q304 and Q307 this past sunday. And compared the readings to my working unit while having both units set the same. Even verified with diferent scopes to see what is happening. On the gate of Q307 I was getting the signal of 24.7526 (selector on 20) I removed the coax at node "P" at the gate of Q307, At the gate end I had no reading on the conter. On the coax end I had the 24.xxx signal.
I see a tie-in to IC308 and IC 310 - both getting input from the Master oscillator. You're getting 24.7xxx and missing 6 MHz from it. Only wonder if the output of the master Oscillator has weakened to a point where clock tracking is affected by power supply noise. IF you need 6MHz, it's gotta' find the timing by counting off the two oscillators shift off a signal then continue the run - to me - my biggest headaches were from the green mylar Chiclets that "supposedly" filtered the TTL noise out and reduced ripple and the spike noises back then in the Personal PC 6502 series chips - a bad clock wasn't really the problem - it was the power supply sourcing then these things "paused" to handle interrupts - sometimes they'd miss and you'd get the lockup from unexpected address "garbage" - it missed a pulse train due to interpreted a spike as a clock pulse.
I will go back and revisit this area and take more readings.
So, what is the general health and output signal level of Q304 and Q307 into the counter IC's? (If the coax jumper can be removed, verify high - impedance across the input - no shorts only to the respective ends of the coax jumper at each end - no kinks...
The coax is very easy to remove. It is a good way to isolate stages and do test. I will revisit this area also.
I'm thinking signature may be needed to see if 6MHz pulse train never gets summed...referring back to the PLL getting timing - but the clock interrupt causes the missing pulse train - especially if the frequency of the 24.7xxx really bounces by proximity of your hand or lead capacitance from the probes - it would explain how you're pulling the clock pulse for timing but the shift is too slow and gets missed - that may be a noise issue onto poor signal level onto something even more exotic..
Regards!
:+> Andy <+:
Yep. It does not take much to load these circuits down. Again this is one good reason that I have one working unit here. I plan this week to take lots of measurements both voltage and scope and add them to the overall schematic. Those caps you are seeing on the schematic are Tantalum. No electrolytic on the PLL board. Most of the time when a tantalum fails it leaves a horrid explosion crater at ground zero.
I have a feeling this is going to be a long repair. But once we understand more of what is going on in this maze of discrete logic the more we can find.
In the snippet below you can see R385. I am going to pull R385 end up near IC316. I will then attach my variable power supply at that point and see if the VCO is actually tuning. From what I see here we should have a tuning voltage of 1 to 6 volts DC. On channel one I measured 14 volts at that end. Very high. This tells me there is some out of lock error there. I just have to verify more on the working unit. For those that need to know the varactor diode and be replaced by one from a cobra 29.
Wished I had all my notes here at work that I written down over the week end. I plan on putting this on the schematic also.
What we need in more theory :)
I think this train ride is going to be wild.
-
Greetings!
Ok, I'll back off a little - you looked like you needed a second, third or fourth opinion on some stuff but by the way it looks - reading by your experience - this is going to be a tough dog to teach...
Regards!
:+> Andy <+:
No need to back off. All good. I just need to verify things. Plus at work so my replies from here are short, quick, then back to work. Lot of wondering eyes here.
I will say this unit has one of the strangest PLL circuits I ever ran across. And this is only the second one I have had my hands on that has a PLL issue. The other dozen or so I worked on were audio board issues, low output, attenuator problems. I think once we have a schematic with more data on it, waveforms and voltage measurements, things will become more clear.
Lots of work here to do....
-
Hmmm, I quoted a post and things when hay wired, never seen this happen before.
Let me see if I can fix it.
K got it fixed and here is my reply
Strange, My eyes must be going on me. I never seen that varactor diode there. I knew there was one at 306. Not sure why they put a varactor off the crystal like that. interesting.
-
While doing some testing tonight I found a little something that is not correct.
The signal of 10.240 enters IC308 pin 1, This is a divide by 16 on the output pin 11. Should be 0.64MHz. But I am getting 60.28KHz.
First pic is area on schematic.
Second is pin 1
Third is pin 11
-
Hmmm, You may be on to something Andy. :D
I called myself checking the supply rails, but fail to check the health of them. Also I checked the supplies at the source and not at the PLL board.
Rats, another reason why I should invest in a Constant Current Dummy Load. Thought I would get by building that little 2 amp supply. I may be seeing a used Agilent in my future :)
When I leave the salt mine today I may pull the 5 volt rail and attach my DC 5 volt line to the input of the PLL board. Then take another reading and see what I find.
Well looks like I may have to take a peek under that bed. All the supply filtering is done on the audio board. And is a pain to get into.
I will let you know what I find.
-
For those playing along at home here is the power supply schematic.
(http://gokarters.com/smf/index.php?action=dlattach;topic=2416.0;attach=1632;image)
-
I have not even started the yard clean up yet. I have 4 days off after today. Perhaps I will begin......But who knows :) Rain coming.
I live on a sand dune. Yes, sand dune. I am 14 feet above the main road. There are many sand ponds around my place. So that means lots of skeeterz.
Not sure if I will get anything done in the shop tonight. But I want to pull out the Tek And the CS-61 scope and look at these signals again. Sometimes a DSO will pick up artifacts and put you on a hunt. And I have to agree that these logic devices do not like noise but pure sign waves. Really makes me wonder what B&K was thinking when they designed this piece of gear. Does not follow their usual quality. But since it was aimed for the cb market....They were just testing the waters and their competiters, Sencore.
I really am starting to question the 5 volt rail more. So will check ripple on that and see what it looks like.
C2 and C10 make be some real killers.
-
Ok, I am home. Looks like I had a bad bad scope probe.
Less than a yeaar old too.
See if this looks better.
First is IC308 pin 14. Correct frequency
Second pic is output. Wrong frequency.
Output is a square wave with lots of ringing at 639,9 KHz
-
Disconnected the 5 volt rail. Injected 5 volts from an external source. This supply looks a lot cleaner than the 5 volt rail in the 2040. But made no difference in the waveforms. In fact, they were identical. What I did find was if you drop to voltage below 4.7 volts it shuts off and has no output at IC308 pin 11. These chips like the correct voltage.
Next thing is to recheck the output on my working unit and figure out why I do not have the correct frequency on pin 11.
-
At this point I connected the 5 volt rail back up. Grabbed the good 2040 and checked the same two locations.
Difference is not much....
Now confused.
-
Looking for a way to kick myself in the butt!
Cant believe I made such a noob mistake.
Sitting here trying to figure why the output on IC308 is not 064MHz.
Why was I getting 639.999 KHz.
Well there is your answer. Bashes head on work bench till it becomes numb.
NOOB!
Yeah I made a mistake.
Forgets IC308 and moves on.
-
OK, making more progress. I do not have the correct frequency out of the VCO going into pin 10 of IC303. So the correct mixing is not there to supply IC303 pin 2 the 6.485MHZ signal. (CH1).
Following the missing signal to IC302 pin 10 takes me back to the VCO again.
-
Greetings!
I'd be taking a soldering iron to re-heat several joints in and around the power supply connectors in hopes to reduce voltage drop across oxidized contacts...
Regards!
:+> Andy <+:
Thanks for that lesson there Andy. All this IC logic and stuff is really new to me. And I think you hit on a few things that is vital to the operation of these things. I had a friend many years ago that ran an Arcade service. What he did was buy and rent these to different locations around the county. I would stop in and his dad would be in the back room with a roll of solder and a iron. I ask what you doing, his reply was "I don't know, this is what they told me to do when these quit".
He knew nothing about electronics but did know he had to reflow solder joints.
Anyway this is why I quoted this part of your post.
As you can see in the pics below the PLL board is not bolted down. Just sits in a foam shell inside the internal RF shield. It has stiff wire connections that run to feed throughs that lead out of the box. Then there are chokes going to more feed throughs that lead out of the outer box.
While checking a few things I decided to lift the board from is resting place to peek under it. After that I placed it back in and fired it up.
The darn thing started working lol.
I am able to even reproduce the fault by wiggling the board a bit. So one of those stiff wires has a bad connection either at the board or the feed points.
First pic is how the board rest in the internal shield
Second shows these stiff wire connections
Third pic is the crystal oven in my newest 2040
Forth pic is the oven in the failed 2040
Next thing to do is re-solder both ends of the connection wires and a few spots on the board. Specially under that oven!.
This should put the unit back in operations.
Since there are no electrolytic on the PLL board I have to pull the audio board out and replace those caps in the power supply. Kind of strange to put the power regulation on the same board as the audio circuits eh?
Then finally reconstruct the oven enclosure. Not sure what type of foam they used here. But it has to be pretty tough not to melt. Well this one did but the other one has not. When you turn the power switch off the oven stays on.
To keep the temperature stable I have to find something to replace the melted and warped foam with.
-
Have you seen the Nasa soldering tutorial?
If not should watch it on YT. Takes like 10 minutes to solder one resistor lol.
As far as this 2040 generator? What I think took place some CEO pushed the engineering department to develop this thing taking notes from their older unit they had. But wanted more features.
You think this design is bad, wait till you see my tear down of the GAW cb generator.
-
Today I spent a little time on the old 2040. First thing I did was remove the PLL board from the unit. Looks really bad.
On the back of the board someone had did some hack job and installed a frequency expansion. O removed all the wiring and really hated what was left.
I cleaned up the board, and traces to fin quite a bit of them missing. So after a little work I got them back in the best I could. I used very thin wore and super glued it down to the board.
-
Yep, the pads were toast. No way to save what was left on them. Well, the ones that were left.
I had to get out the video microscope for this one.
One thing you may have not noticed is the entire top surfacew of the board is a ground plane. You have the traditional traces on the bottom. But everything on top is at 0 voltage.
I had another one in a year ago that lost RF output. Through the output stage one pin lost it's ground on the top side of the board. MAn talk about a pain in the rear to trace that out. Pins grounded on top do not connect to anything below the board.
All connections in and out the RF enclosure uses feed thru caps.
This one is going to be fun. I have the board out of the box and connected up for testing.
Will post more back later :)
-
The saga continues. A good friend I was in conversation with brough up a good question after I told him there was no output on the mixer IC302. I have a good signal on the input pin 1 of 20.48 MHz. I had already checked the gate of Q307 for a VCO signal. This runs the generator output fruequency when in lock. So if it is not locked the mixer will output the sum of the frequencies.
Anyway I went back and checked pin 10 of the mixer, there was no signal. But yet there was signal at the source of Q307. So for giggles I clipped the output side of C319. Bridged a 4.7pf cap across and bam, the generator cam to life. So for a year and a half C319 has been the smoking gun. And when replace the unit locked.
Still have to address the channel selctor in this unit. No matter where you put it , you get 27.205 on the output.
IC306 and 307 are my first guess, Reason, because there has been previous work under them before, and both are in sockets.
So there you have it folks, you are getting this live as it comes. And there is more to come...
-
Here is a snippet of the problem circuit. Thought I had attached it last night.
I will post how this works later.
-
I have a B&K 2040 that has been working fine for years, the other day i had a radio on it and noticed that the signal was very weak. checked coax and radio and they were working good, the 2040 other functions all work good. have printed a schematic for it, just not sure where to start. I can hear the tone on all settings, but its just not very load in the speaker of any radio. I have another 2040 that i would like to get fixed to, if there is some one out there can can fix them and align them, i would be happy to send them out.
-
I have a B&K 2040 that has been working fine for years, the other day i had a radio on it and noticed that the signal was very weak. checked coax and radio and they were working good, the 2040 other functions all work good. have printed a schematic for it, just not sure where to start. I can hear the tone on all settings, but its just not very load in the speaker of any radio. I have another 2040 that i would like to get fixed to, if there is some one out there can can fix them and align them, i would be happy to send them out.
It is possible you have a shorted resistor (or open) in the attenuator section. This can easily happen if a radio accidently keys up while connected to the generator.
It is also possible that Q312 and Q313 could be bad. These are the output transistors.
-
Thanks! for the help, i have not checked Q312 Q313. But what i did notice is the tin box in side was very hot at one end, opened it up and found that R309, R310get really hot and some of the parts around it. Can't keep it pluged in to long or it gets so hot you can't touch it, not sure if this should be warm or not sence it is a 50 ohm load resister. It has always been pluged in to my 1040.
thanks! radio tech for your help
-
Thanks! for the help, i have not checked Q312 Q313. But what i did notice is the tin box in side was very hot at one end, opened it up and found that R309, R310get really hot and some of the parts around it. Can't keep it pluged in to long or it gets so hot you can't touch it, not sure if this should be warm or not sence it is a 50 ohm load resister. It has always been pluged in to my 1040.
thanks! radio tech for your help
Looking at the front of the unit are you talking about the left side that is getting hot? If so, it is going to be hot. That is the crystal oven. It gets really hot in that area and keeps the crystals at a certain temperature.
-
I hate to bring up an old thread but since there's only a few, I guess it's ok, haha.
I've got one of these also, checking the output on two different frequency counters, I see 27.183 on channel 19. Well actually on the BK 1801 counter, I see 27.184 and on my Victor VC2000, I see the 27.813 reading. I opened up the crystal oven to adjust the trimmer as per the service manual... well, made no difference and it looked kinda bad. On the side of it is 8-60, that's the only number or markings on the piece, I figure it means 8pf on the lowest adjustment and 60pf on the highest. So I ordered something very close from Digikey, it arrived today and I put it in as best I could (not the same exactly as what came out). So I get the same exact adjustment ranges or frequency, still off by the same readings.
Those two crystals that are inside, the 10.240 and 10.243 mhz. On the 10.243 crystal, using the oscillator built into the frequency counter I get 10241.457 kHz which is two off from what's marked on the part. Which is also two off just like the frequency output of the generator. Could this be the issue?
The 10.240 piece, I get 10239.657 or so... which is almost dead on for what's marked on the part. Other than being slightly off frequency, it seems to work just fine and I only noticed it once I hooked up an inline freq counter on my bench. I attempted to find one with Google, seems they don't exist any more, so where would I find a crystal to replace the 10.243 one with?
-
The 10.240 looks ok. The 10.243 is off quite a bit. I am not sure if I have any more in stock but I will look. This is not an off the shelf part. But a custom cut crystal for these units.
I would contact ICM:
https://www.icmfg.com/
Let them know what you need and cut the crystal for you. They are about the best I know of.
You have to remember the age of this unit. And that oven plays a toll on parts. Check all the capacitors in that area to be sure some have not moved too far off. Should be a capacitor from crystal to ground off the 10.243.. If that cap goes out then the crystal will go off frequency.
-
BTW
Welcome to the forum. Are you the PorkChop from CBT?
-
That would be me! I found this site by luck looking for a solution, looks good and lots of cool stuff here!
I put it back together cause I needed some sort of generator to check a radio, it now shows 27.1849 on the 1801, haven't checked with the other counter yet. I did email that company though, guess I picked wisely huh? I'm going to replace everything in that section, just got to order the parts.
I really like this generator and I have the whole setup including the scope for it but it's a POS. Looking for another scope, just don't know what I really should buy, guess it depends on what I can afford.
-
Cool. Hope you will find stuff here you like and can use. Not a lot of activity here. It comes and goes. But I spend most of my time here.
Good thing about the generator is it is still usable. Although it is off a bit. Let me know what you find from the email.
Sort of hard to suggest a scope. Not knowing just how in depth you want to go. If you are looking at expanding your knowledge and getting deeper into electronics then a Rigol DS1054Z is a good all around 60 MHz 4 channel scope hackable to 100 MHz. If you just want something to use with the gen then about anything you find should be ok. What model do you have now?
-
My 2040 as best I can tell is dead on the modulation side. When you turn it on the meter doesn't move and the green light comes on for a few seconds then turns off. The mod meter doesn't move when adjusted and it doesn't move with the af adjustment either but the lights will change from + to - on the af side. I haven't as yet hooked it to anything to see what I am getting but first assumption is I got problems.
-
Ok, so I emailed them and the reply I got was that they needed the holder style and load capacitance in order to make one. SO.. this is where my ignorance will shine through, I don't know what the holder style is, I saw it somewhere but don't remember what site I was on when I was comparing them. And I have no idea about the load capacitance... how might one find that out?
The two scopes I have now are by BK Precision, a 1474 and a 1474B. Both of which I think are trash, I believe it'll take way too much work to get them back up and running and I really want something much newer, like what you're talking about. So I'm thinking about tossing these two relics in the trash.
BigMic919, don't be afraid to pop the lid off and look around. Start testing some points in it and see what you get, it's possible it's something simple and easy to fix unless you need the same part I need... haha.
-
Porkchop
The holder is HC-18/U. I cannot remember the load capacitance. I do have it written down somewhere. One thing we have done in the past is send the old crystal in and they can figure it out.
Bigmic
In the video above the same chip handles that section. it is a quad op-amp. Maybe be bad or missing voltages.
I can get more detailed on all this by the weekend guys.
-
That is where I was going to start. All I have is a 20 mhz scope will that work to check it out?
-
That will work,
-
I checked it out and have signal on the scope at the input but nothing at all on the out put. I also noticed it looks like IC1 has been changed out as well if that makes a difference. Where is the best place to get these parts?
-
Well boys, it appears mine has taken itself a dump. I turned it on a few minutes ago to check a radio... nothing. Well, the yellow/amber light about meter function burned steady even though the switch wasn't flipped. I checked the output with my frequency counter and basically got nothing. Turning the modulation and power knobs, the meters increase but I'm not getting anything out. I opened it back up and checked before the signal left that box in the back, nothing there either.
I don't get it. It was working fine. I turned it off and it sat in here for a few days, now it won't work. This really puts me in a bind, can't check this pile of radios I have without a generator... dang it BK...
SO I guess this means I'm gonna have to buy a new one or new to me.
-
Ok got the time to check Q312 with the flat side facing to the left, top pin is 12.89v, middle pin 12.18, bottom pin 0. Q313 top pin 12.98v, middle pin 12.13v, bottom pin 0. the oven has melted the styrofoam cover just like in the other post.
-
Tell me more about that scope you mentioned. I bought a Marconi 2018 to use until I can figure out the 2040. Of course, I'm gonna use the 2018 but I still like the 2040.
That 2018 also showed me that Victore freq counter was off ass well.
-
Ok got the time to check Q312 with the flat side facing to the left, top pin is 12.89v, middle pin 12.18, bottom pin 0. Q313 top pin 12.98v, middle pin 12.13v, bottom pin 0. the oven has melted the styrofoam cover just like in the other post.
Those sound correct. I will verify just as soon as I can.
Real busy here this week. Those covers have melted on about every unit you see now.
-
Tell me more about that scope you mentioned. I bought a Marconi 2018 to use until I can figure out the 2040. Of course, I'm gonna use the 2018 but I still like the 2040.
That 2018 also showed me that Victore freq counter was off ass well.
One of the best scopes for cb repair is the Sencore CS-61. It is a great unit. The Tek 2235 is another good unit,
-
Buddy, I have been watching your videos and reading quite a few of your posts. You are a good tech sir. I started out in electronics but moved to a different field years ago. I still love radio and love to tinker on my bench. I have been thinking of getting the 2040/1040 set to align my radios and then friends radios once I have proven myself.
Two questions: 1, what if any are the things to watch out for when buying the 2040/1040 on an auction site? I know they will likely need some work and an alignment. 2, Any chance you will do a video demonstration the alignment procedure of a CB radio?
Cheers
-
Buddy, I have been watching your videos and reading quite a few of your posts. You are a good tech sir. I started out in electronics but moved to a different field years ago. I still love radio and love to tinker on my bench. I have been thinking of getting the 2040/1040 set to align my radios and then friends radios once I have proven myself.
Two questions: 1, what if any are the things to watch out for when buying the 2040/1040 on an auction site? I know they will likely need some work and an alignment. 2, Any chance you will do a video demonstration the alignment procedure of a CB radio?
Cheers
Hi Derrick and welcome to the forums.
The 2040/1040 is a great unit to have. Really nice at alignment.
Is cb all you are interested in?
If yes then it is fine. But for the same money you may can get a better unit that will cover ham radio frequencies. This is more versatile just in case you want to expand your knowledge. Something like the HP 8640B. Gave 100 bucks for mine and had it repairs in less than a day. Covers 0 to 500 MHz. Signal gen only.
With out being able to touch the unit not much you can really do. If buying on ebay use paypal and read all the sellers fine print. Even if buying from an auction pay with a secure credit card that can get your money back in case it is not as advertised.
I have been planning to do that when I can get time to start my new series on learning RF radio electronics.
Thank you for your kind words.
-
CB is not all I am interested in, but I don't know how much I will/would align ham equipment and tend to be more interested in working on my old CBs in this way. Also, I am under the impression that the the BK 1040/2040 set is probably a good gateway to aligning radios and getting familiar with the process. I am under the impression that it is set up almost like an "alignment for dummies" book would be. I have a BK 20mhz scope and 9 digit frequ counter. I also have a Fluke DMM, analog meter, dummy load, power/SWR/tuner, and other equipment on my bench already so along with my electronics foundation from years ago, I am hopeful.
As for buying the BK set, the auction option is the only way I can find one and I don't do PayPal since I won't give up my bank routing #. All the auctions say "selling for parts/as is" so they have no liability and since they are all like that, it sounds like my only option is to risk take a big change on buying a non-repairable set of junk. That would be really hard to handle.
-
CB is not all I am interested in, but I don't know how much I will/would align ham equipment and tend to be more interested in working on my old CBs in this way. Also, I am under the impression that the the BK 1040/2040 set is probably a good gateway to aligning radios and getting familiar with the process. I am under the impression that it is set up almost like an "alignment for dummies" book would be. I have a BK 20mhz scope and 9 digit frequ counter. I also have a Fluke DMM, analog meter, dummy load, power/SWR/tuner, and other equipment on my bench already so along with my electronics foundation from years ago, I am hopeful.
As for buying the BK set, the auction option is the only way I can find one and I don't do PayPal since I won't give up my bank routing #. All the auctions say "selling for parts/as is" so they have no liability and since they are all like that, it sounds like my only option is to risk take a big change on buying a non-repairable set of junk. That would be really hard to handle.
Another good thing about the combo 2940/1040 they are repairable. Nothing really in the unobtainable list yet. So yes you can buy a dead unit and fix it. Just takes time. There is service info on line and I have a couple of videos on them. I do have another unit (one of mine) that has developed a PLL problem.
-
Very nice! Do feel free to PM me if you hear of a 1040 or 2040 up for sale.
Best regards
-
Sure will.
-
Porkchop
The holder is HC-18/U. I cannot remember the load capacitance. I do have it written down somewhere. One thing we have done in the past is send the old crystal in and they can figure it out.
If you run across that load capacitance for the 10.243 MHz crystal please post it because I need to try to get one of those. I have a 2040 that is off frequency and upon inspection of the crystals, I discovered that BOTH are 10.240 MHz in my unit (the one that should be 10.243 has obviously been replaced at some point with another 10.240 MHz crystal.