KENWOOD TS-520 - Finals replacement
Вставка
- Опубліковано 19 сер 2024
- In this episode we witness the trials and tribulations of changing the 2 x 6146B PA valve (tube) finals in my KENWOOD TS-520. I also briefly discuss how thermionic valves (AKA vacuum tubes) operate. 73 de VK2AOE @TheArtofEngineering
Antique Electronic Supplies - Where i got my final PA tubes
www.tubesandmo...
Microwave1 MIKE Channel - Awesome content on all things ham with a focus on old school tech
• TS-520 10M Fix and Neu...
/ @mikrowave1985
Mr Carlson's Lab - Great channel about electronics repair with LOTSA vacuum tube stuff! This guy is SMART!!
• How A Tube Works
/ @mrcarlsonslab
HAM PLAYLIST LINK:
• Ham / Amateur Radio
Merch
My REDBUBBLE store for Merch
www.redbubble.....
Chicken channel logo shirt
www.redbubble.....
Brains from the Thunderbirds Merch
www.redbubble.....
I have watched a few of your videos ans have found them entertaining and often quite informative.
You must have the world's toughest feet!
73 K1AUS
Yes ! My 🦶 pick up component leads, broken glass and food crumbs. Saves me time vacuuming 🤣. Thanks for the kind comment de VK2AOE 73.
Which might mean that the filament supply or some other part of that driver tube is loading a supply causing the issue? My TS520 I changed all large electrolytic caps (not every cap). I’ll look at a cct diagram and have a think about it. 73 OM
Darn good opening advice!
It cant hurt to thoroughly clean the glass envelopes and pins so contaminants dont burn on.
Also, according to the tubes plate curves, the 6146 and 6JB6 are the same tube except the 6146 is twice the plate dissipation rating, and one less base pin. They have the same biasing and operating point(s).
The electrons jumping into a cloud is a myth.
The heat reduces the Work Function requiring less plate to cathode potential to cause them to come off.
If not, current could flow without extrrnal bias.
Thanks for the comment. Could you point me towards some information that confirms the electron cloud is a myth? It wouldn’t surprise me that this is true (as even the current flow analogy to water is SO NOT reality) but a quick search didn’t offer any info. Thanks for the comment. 73 de VK2AOE.
I own 3 ts 520 knwds. I do not have to say I hold them in high regard
One is brand new in the box ! I do not mean I still have the box !
I mean it is still brand new in the box
I bought it from a fella who bought the rig then never got a ticket
He never even opened the box :)
I had a uncle who retired and moved to costa rica
He brought his 520 with him. He used it for decades and never had a single problem
Still had the original tubes !
The 520 was built during a time when the japanese were making bones
A kenwood was of a bit higher quality the the rest
We will surley not see such a robust piece of gear again
I only operate QRP cw nowadays and will likely never fire up my 520 again
I wonder if you read the service manual
I changed a set of tubes a long time ago in one of my rigs
I used only a multimeter a oil cooled dummy load and a fiberglass rod I made into a screwdriver by sharpening the end
I had no problems
Yes ....Unfortunately a digital meter won't cut it for the neutralisation, an RF voltmeter is recommended and not that common as test gear anymore. I used my oil filled dummy like you did (homebrewed)....and for the neutralisation a tap on a dummy fed into my SDR to look for the null. I did read the instructions in the operating manual (don't own a service manual for it). They are amazingly well built...I doubt in 50 years time any of the rigs around today will be alive. I always get compliments on the audio when working SSB. I do fire mine up, but like you prefer QRP and rigs I have slaved over to build. My homebrew efforts thus far are VERY modest ...but that first QSO on a completely homebrew station was priceless!! The TS520 since changing the bottles has been good! Nice to own ham history. 73 watched this guy on UA-cam too
ua-cam.com/video/v0EmyyYNy00/v-deo.htmlsi=LK5bMnjbE_03i1F1
Yes I a big fan of that fella too
He not just a hobbiest@@TheArtofEngineering
Thermionic valves: FET’s with pilot lights. 😉
Big FETS! 😜. Tnks fer the comment 73 de VK2AOE.
I typically use 8298A junk pulls and neutralize. Or is it Neutralise?
Hi good video..but cathode is a "C" typically...hence looking like a C
Quite often in schematics you will see the letter K to denote cathode. My understanding is this is because C is for capacitor and because it is a Greek word and there ain’t no C in Greek… bizarrely except my Greek surname… that starts with a C ….
73 de VK2AOE
electronics.stackexchange.com/questions/65981/why-is-the-symbol-for-cathode-a-k
Hi mate, I have been watching your youtube videos and trying to tune in my 520 I am so confused. I am not sure if it is even working. I am getting a little bit frustrated. I definitely need some help.
Are you just tuning it to transmit ? Or have you replaced the tubes with new ones. If just tuning for transmit watch this video
ua-cam.com/video/40Inq07Spd4/v-deo.html it helps to have a 50 ohm dummy load but if you know your antenna has an SWR below 2:1 you can tune it “on air”.
Hello
Would you be so kind as to give me some advice?
I have a Kenwood TS 530s with the following symptoms:
In RX:
heater=off, Reception is correct.
heater=on, Reception is lost.
In TX:
Selector in SSB:
IP readings: reading 0 Even negative,
ALC readings: reading 0 Even negative,
All components of the final step plate are in good condition.
Could it be a valve12BY7a problem? or the electronics of its periphery?
Thank you.
I am by no means an expert. Obviously be very careful as the voltages are deadly!! Only proceed if safe and you know what’s going on. Have you tried with driver tube removed and heater switch on…. To see if that kills receive? It is an interesting fault? Let me know what caused it, when the solution is found? I will keep my ear to the ground and if I hear anything helpful will pass it on 73 de VK2AOE
@@TheArtofEngineering First of all, I can't be more grateful for your quick response. This equipment has just arrived in my hands because I really like valve equipment. They seem like engineering jewels to me.
I have carried out the test that you propose, If I remove the Driver valve, 12BYA and right after I activate the heater. The reception is perfect, it is not lost.
Thanks again
Apparently it could seem like a valve problem. I don't rule it out. What happens is that I have tried a second valve and the problem persists.
Unfortunately I don't have a valve tester to know what condition these two valves are in.
Toocrappy
No it is antique! 😂😂