#56 B&K 2040 Signal generator PLL issue
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- Опубликовано: 28 авг 2024
- In this video we troubleshoot a very fine piece of vintage CB test gear. CLICK SHOW MORE
Inside the unit we find that the 3 74161 program divider chip failed in a cascade format. We also find that IC307 took out a resistor. After replacing the failed components we get the unit back up and running.
Link to site for schematics and service manual:
gokarters.com/s...
What to help out? Mail Items, donations, shipping :
gokarters.com/s...
Thank you I learned alot from you, thanks an have a great new years.
Side note, noticed at about 38:19, that R360 at IC-307 appears to be "cracked."
Yep, the 4.7k does have a crack in it but only on the outer shell. Resistor tested good. Good eye BTW.
I just picked up one of these cheap off Ebay...
failed mod attempt and cracked circuit board... This is going to be fun!
Good job on this one man! I would have been lost as a Thanksgiving Turkey on this one.🤣😀
With the voltage difference between that first transistor you tested, between base and emitter, seems like the base emitter junction is biased off ? So, one would need to find out why its biased off. But, it might not be bad, unless the base emitter junction is shorted. I think your decision to look elsewhere was correct. I have a CE-6 with a PLL unlock condition right now.
Also nice to see I'm not the only person that loves the rainbow packs of highlighter's. Makes tracing out circuits on a schematic so much easier.
I love my colored markers. Brings out the kid in me. :-)
That's good work. I haven't used my old B&K 2040 in years. I took it out of the box and plugged it in and it still works. Tuff unites back in the day.
Much appreciated. Great little units.
Very Nice Job.
Thank you very much MrMac
OIC, you replaced a few moments later...
Great job Buddy, that 14.1VDC on the base made my head turn a twitch when you first called it out as well. Problem is when you find an error then you start to think what else may be wrong; often it's a singular error but you start to question things a lot more as you work your way thru the problem using the documentation. 73 - Dino KL0S
You are very correct Dino. The really bad part is when new want to be techs start troubleshooting and see an error like that. They may even apply the missing voltage from an outside source and things then get real messy. But from experience We see the voltage on the transformer side (T301) is in the millivolt range on the collector, the emitter will have less than 5 volts since it is fed through two resistors. And the base can only have about 2 volts since it is tied to 10.240 MHZ signal path. 14.1 volts would had made things interesting.Thanks for watching my friend. 73 Buddy
Hey all. I had cut one part of the video due to some test gear noise. I could not hear it but the camera sure did. This was the alignment part of the unit. If you remember when testing the output of the SG was 5 channel wide. After an alignment it went away. This was due to max setting and VCO out of adjustment.
Ahh, I was wondering whether the alignment resolved that. Thanks!
Ahh thanks I kept hunting for the answer and thought I missed it!
Well at least I'm not the only person that was doing some head scratching on one of these. I ran into the same thing with the 14.1 volts listed on the base of the transistor once. Looked at the schematic and came to the same conclusion, no way. Got to love when the service manual is wrong.
Yep, that was a brain twister. I have never caught that one before. I think they do it to make you prove things out.
thats an interesting method. i never thought to solder a socket right over cutoff pins. i have the right tools but maybe on a really sketchy board ill try this.
Really helps on delicate boards. This way you do not destroy anything.
"""Brian Ray. Awesome video, I learn so much watching you, even down to the basic things that I see you do in your videos. Great views such great close up shots and in focus. You explain everything so well. Keep up the good work and thanks for your time"""""""""For some reason I am not able to reply to your post. Other folks cannot see your post. But thanks for the kind words.
Excellent explanation of fault finding. Well done.
Thanks you
Awesome video, I learn so much watching you, even down to the basic things that I see you do in your videos. Great views such great close up shots and in focus. You explain everything so well. Keep up the good work and thanks for your time
i wonder if some of that extruded board insulation would work better than the white styro?
G'day Buddy, that was good fix and time consuming . One small part blows and takes 3 ics, I like the way you explain the voltages. I'm looking forward to one day when you get a FT101B on the bench. God Bless you and your family. Thanks for sharing 73.
Thanks Dennis. Very glad you liked the video. Was an interesting failure in this piece. FT-101 eh? I have 5 in the shop at all times. Any particular part of the 101 you interested in?Many blessing to you.buddy
My old Yaesu FT101B does not work to good even with cleaning from your previous videos. Would it be better to recap the hole radio. They not leaking the Capacitors. After seeing what you did with the TS520 Kenwood in how clear in sounds. I thought if I would clean it up the FT101B it would sound the same.
Another interesting video Buddy - thanks for posting. Man, I hate it when documentation is wrong. Great tip on cutting out the IC and installing a socket! I'll remember that one. 73, Bill.
Thanks Bill. You really have to keep an eye on documentation from this era.
great video. good luck with the storm ricks radio shop
Another great video, enjoyed watching!
Thanks. Glad you liked it.
Buddy, is it possible to share the channel selector truth chart that you made? Thank you and have a most awesome evening!
Let me see if I can dig that up, I will post it on my website.
Buddy,@@TheRadioShop please post a link when you have time. Thank you and have a most awesome evening!
Do u know the spec for a replacement meter lamp as couldn’t see this in the service manual? Thanks Mark
Really nice Job Buddy. Great video as always and I for one learned allot from this one. Hope u are well my friend and cant wait to see more videos they are superb.
Thank you Gary. I knew it was not going to be simple repair. Every time I work on one of these I learn something else also :) Glad you liked it . Doing great here and hope you are.
Great video.Enjoyed every bit of your trouble shooting.I just bought a marconi 2022 sig gin.Now I need to learn how to use it.I wish you or mike would do a video on how to hook all this stuff up.I had to order a manual for it.Now doubt it will come from the uk,which will take weeks to come.any way,great job.73 from kn4u.
Thanks, If I had one I would do a video on it. The Marconi is a different beast then some of the others so without one it would not be possible to explain how it works.
The Sencore CB42 has the same issue with corroded copper traces.
Yep, same issue
excellent fix Buddy! Yeah this schemas are often wrong but still better than the situation we are facing today..., very often no service manual at all! Was all back to normal after the alignment or still splatter over 4 channels? Thanks for sharing Thumps up. Take care my friend! 73
ah okay have just found your info .-)
Hi Peter. Thanks for the kind words. You are correct on todays electronics with no available schematics. I have a Tenma 72-5000 frequency counter with a bad front end, still found no service info for it. I do know it is a rebadged Tektronix CMC251. But nothing on it either....All fine after the alignment. They had the modulation cranked all the way up in this one. Thanks for stopping by my friend. 73
No problem :-)
Nice repair mate big thumbs up
Thank you allan
Wow very cool Buddy, thx 4 sharing.
Glad you liked it Tony.
I adjusted it counter clockwise until it became loose, it would not bring it on frequency, maybe crystal has drifted to far? or something else, thanks for your great video, looking forward to your response.(on ch 1full clockwise is 26.9622 to full counter clockwise 26.9641) thanks.
great vid!! why are folks putting "73" at the end of their comments?
Thanks
Do you have a 1040 or 2040 you’d sell
any idea why mine is reading 26.984 on ch. 3 and all other channels its off the same amount, also the 455 kHz. is reading 454khz.
That just sounds like the reference crystal is off a bit. .Open the unit, remove the metal shield from the PLL box, remove the next metal shield and you will see a foam block with a hole in it. Adjust that trimmer for spot on frequency.
Hay man your awesome Thank you Thank you Thank you .
Thank You!
I have a bk 2040 I just got, needs some repair. Do you take these in for repair? If so , please let me know. Thanks in advance.....