Good to see no major damage was done. Had to laugh when you said the owner turned it off and retreated to the other side of the room. Reminds me of the first time I accidentally installed a high voltage electrolytic cap backwards. Surprising how much steam and noise a 100uF 500V cap can make. I swear to this day I still cringe a little when I first turn on something tube type after recapping it.
@mikesradiorepair
6 жыл бұрын
NikkiGurlSixtyNine That's a little low voltage cap. Imagine that several times larger and with 460 volts on it. Made for a good light show to.
@TheRadioShop
6 жыл бұрын
LOL. I do the same thing every time I rebuild a unit like this. You are right about those caps exploding. Remember the old Sprague 500 volt caps with the paper cover?, Man those would let a lot of smoke out.
@mellagarde7142
6 жыл бұрын
Hi Buddy Another great repair and so informative. It is wonderful to watch you work and thank you for explaining everything so carefully for us. So many know so much more than me but it is nice how you make it relevant to experienced and non experienced. My best to you today. Mel
@TheRadioShop
6 жыл бұрын
Thanks Mel and so good to see you
@LarryDeSilva64
6 жыл бұрын
Had a resistor smoke when working on my Military signal Corp R336 receiver. Apparently it had been used as a test radio for techs a total of 9 wires were found cut. The worst being inside a big IF can all the screws were unscrewed from the cover and 5 wires cut then it was was screwed back down. That relay sure did make a nice fireworks show and a bit scarey for sure. Glad you were able to fix it and get it up and running again.
@TheRadioShop
6 жыл бұрын
I bet that was scary. I never like seeing fireworks from Thanks for sharing.
@ojjenkins7110
6 жыл бұрын
Another good one Buddy. My current amp is a TENTEC Centurion. I have an Alpha 76A and a 30L-1 as backup, to bad the Collins don't do 160. Thanks for the look under the L-4B.
@TheRadioShop
6 жыл бұрын
Thanks OJ. I do believe there is a mod for 160 on that Collins.
@lylewatts6370
6 жыл бұрын
Yes high voltage is dangerous. Nice amp to go along with the Drake collection. Wait a while for the cap's to discharge. I have worked on SB-200 and FL-2100B always remember about discharging the high voltage after the power is turned off. Thanks Buddy for a very good video
@TheRadioShop
6 жыл бұрын
Thanks Lyle. Good thing about these amps with no power supply connected no high voltage. One reason I like these amplifiers.
@rico1319
6 жыл бұрын
The Drake L4B is now back in service! Another great fix! Great job buddy thanks for walking us through it!👍👍👍😎🇨🇱
@TheRadioShop
6 жыл бұрын
Thanks for watching Rico.
@DonDegidio
6 жыл бұрын
Hi Buddy, Talk about high voltages, was working on my SB221 about 20 years ago and thought I had bled off all the high voltage. Well, there was still several hundred volts and when my hand came in contact the jerk back caused my hand to hit the chassis and slice open the side of my hand. Needed a dozen stitches to close the wound. At least I had survived and it was an unexpected learning experience. 73 WB3BJU
@TheRadioShop
6 жыл бұрын
Wow Donald. Horrible experience for sure. That is mostly the problem with getting hit by something like that. If the current don't get you the obstacles in the way will. Never liked working on the SB221 series.
@DonDegidio
6 жыл бұрын
Have it apart now to convert it to a SB220. 73 WB3BJU
@langhilau
6 жыл бұрын
Great video Buddy, it is so strange that you would do this video since last week about this time I turned on my L4B with the solid state relay in it and the same failure happened. It took me a bit more testing and checking to fix it and make sure I had solved the problem than it did for a pro like you. Keep the quality videos coming I enjoy them more than any other videos on KZitem.
@TheRadioShop
6 жыл бұрын
Thanks Kevin. Did you find a loose wire also?
@louw1qjparascondola821
5 жыл бұрын
Kevin, personally I think you are better off NOT doing this electronic relay mod. You can obtain the exact results this mod deals with by making no mods to the amp itself. You would be much better off simply making a cheap external on switch for the amp by switching the line voltage to the amp cord and leaving the switch in the ON position on the amp. It accomplishes the same thing and you will probably NEVER have a fault like this. Better yet a TRUE step start circuit is still better yet. I would not recommend this mod with other better options available.
@texasvarmint9542
6 жыл бұрын
Ha! Reminded me of turning the HV on my HB pair of 3-500z s once and a big bang. Instead of smoke though, dirt went flying everywhere. A dirtdobber had built across the diode connections. Vaporized that poor fellow. I just recently did the Harbauch mods to my 4-LB. Love that amp, but wish it had 160 meters. Again, nice video Buddy.
@texasvarmint9542
6 жыл бұрын
Oops - L-4B I meant.
@TheRadioShop
6 жыл бұрын
Bet that was a nasty mess to clean lol. There is a mod for 160. Thanks for watching
@texasvarmint9542
6 жыл бұрын
Yeah, I've seen that mod and seems too involved to me. Thanks, Buddy
@TheRadioShop
6 жыл бұрын
A bit involved but well worth it. Save the power switch for sure.
@aussiedazvk4djh889
6 жыл бұрын
Hi Buddy. I'm the same here High Voltage + Big Bang = 🐓 Another great video. 👍
@TheRadioShop
6 жыл бұрын
Thanks. High voltage can be a scare to work on.
@montygore1200
10 ай бұрын
I wish I had known you when I retired. I had boxes of l4b parts and many other parts. I had parts that cant be found anymore.
@Ronnie9710
6 жыл бұрын
Good job Buddy.I wanted an L4B for the shack,but sense I use a LDG pro 1000 auto tuner,I settled for a SB1000.Added a soft start ,a wafer on the selector switch and a little solder work and it been a good amp.73 from Ronnie
@TheRadioShop
6 жыл бұрын
Good deal Ronnie. They are great amps. Thanks
@cuban9splat
6 жыл бұрын
Good job on that L4B, Buddy. It is always a pleasure to watch someone like yourself that knows what they are doing. Mt amp is the old Heathkit SB-200. She has a few issues that I haven't figured out how to fix yet, both mechanical. One problem is the TUNE knob is stuck on the shaft and the set scew is broken down inside the knob. I think I am going to have to butcher the existing knob to get it off, then replace it LOL. Thanks for the video. 73 DE K7RMJ Frank
@TheRadioShop
6 жыл бұрын
Thanks Frank. You may be able to drill that set screw out. Have done this to a few.
@michaelhiggins7365
5 жыл бұрын
Another great video. I would like to see your setup for bleeding off the High Voltage before troubleshooting. Thanks for all your teaching me.
@PapasDino
6 жыл бұрын
Nice fix Buddy...usually the 0.82 ohm "safety resistor" in the HV supply is what pops. I've been maintaining and fixing my L-4B since I bought it new in 1979. The Harbach soft start kit is what I have installed in my two L-4Bs. Just about everything that can go wrong has done so at one time or another but that amp just keeps on purring and the only microprocessor installed in it that can burp is the one between my two ears! ;-) 73 - Dino KL0S
@mikesradiorepair
6 жыл бұрын
Dino Papas As long as that microprocessor doesn't burn out all is well. ;-)
@TheRadioShop
6 жыл бұрын
Thanks Dino. I will say they are one of my favorite amplifiers to work on. Had plenty of those 0.82 ohm resistors blow. I think I still have 50 or so of them in stock. One thing about it, these amps can erase that micro between the ears.....
@PapasDino
6 жыл бұрын
That's for sure, if you're not comfortable around VERY high voltage leave it to someone who is - it WILL KILL YOU. I've rebuilt several L-4BPS power supplies for folks and even replaced one of my supply's transformers with a higher voltage unit (Hammond makes them now; a couple of KL0S Shack Notes describing that fix is on the WB4HFN website along with another about a fix for the 3-500Z socket to fix the tube pin problem you described).
@old64goat
6 жыл бұрын
Great repair Buddy!
@TheRadioShop
6 жыл бұрын
Thanks Bill
@150leftseat
6 жыл бұрын
Hi Buddy Thanks for your all your videos, always enjoy them.
@TheRadioShop
6 жыл бұрын
Thanks
@ne2i
6 жыл бұрын
More Drake Please!
@TheRadioShop
6 жыл бұрын
I do not get many Drakes in for repair. Blame it on the quality lol. I am looking a pair of Drake twins.
@SV8DJW
Жыл бұрын
Thank u. Great video. Its a little dangerous to control the relay input straιght from 220v without a transformer.
@76_138
6 жыл бұрын
Thanks for your videos they're very educational informative I greatly appreciate it thank you very much thanks once again Eric
@TheRadioShop
6 жыл бұрын
Appreciate that Eric
@pierrelataillade7564
6 жыл бұрын
Yes indeed Buddy...240 volts will get ya. very nice fix... thanks
@TheRadioShop
6 жыл бұрын
Thanks Pierre
@Lee-NN7X
6 жыл бұрын
Great Video Buddy..Thanks..
@TheRadioShop
6 жыл бұрын
Thanks Lee
@plsummittsummitt5026
3 жыл бұрын
Thanks for the video bro.
@rdpecken
6 жыл бұрын
Buddy, It looked like the diode that you checked after the 1N4007 was shorted. The meter read zero ohms (or close to it) from the digits that were visible on the video (8:49). That would explain the blown resistor. Have a look and see if you agree. 73 de Randy wb0smx.
@TheRadioShop
6 жыл бұрын
Yes it was a zener diode and was opened. I replace all the components in that circuit.
@billnicholson2470
3 жыл бұрын
Great video Buddy. I would also like to see exactly how you discharge all of the caps before you start. I have an Ameritron AL-811H that is fine but if I ever take toe cover off to clean dust and such I would like to know the high voltage is gone. Thanks for sharing. Enjoy all of your videos alot.
@joesteele8466
Жыл бұрын
I have a Drake l4b unkeyed I have 80-something V DC bottom of the tube when keyed it goes to zero not getting my 3 V zener good yellow word seems to be dead out of the Transformer is this the problem or not
@AF6LJSue
6 жыл бұрын
Good Deal
@TheRadioShop
6 жыл бұрын
Thanks Sue
@boxingday11
6 жыл бұрын
Thanks Buddy for the upload, can tell me how you can check the vswr through the input tuned circuit with the power off, I have an sb220 and need to adjust the input side for 80m as it's a little high but am a little nervous to do it while the full 3k volts are on. My best regards,hope your keeping well, Carl.73.
@TheRadioShop
6 жыл бұрын
High Carl. I have used a MFJ ant analyzer to do that. You will have to engage the relay manually.
@boxingday11
6 жыл бұрын
Thanks Buddy, I shall try that and let you know how I get on . Regards from Carl.
@pinponelmono
3 жыл бұрын
Hello have you ever replaced the air blower? mine, the turbine turned to dust. and now i dont find any that fits... thanks!
@anselb2000
6 жыл бұрын
Nice repair. Glad that was all that was wrong with it!
@TheRadioShop
6 жыл бұрын
Yes me too. Very easy fix this time.
@RobertHallIV
Жыл бұрын
I'm sorry, my brain won't allow me past the 8:54 mark on the 2nd rectifier. That thing was shorted forward and reverse, right?
@richarde735
3 жыл бұрын
have you ever converted an L-4B to work on 6 meters? some of the newest models lack 10 meter too, which may limit the ability to add 6 meters
@goturtags6121
5 жыл бұрын
My dad has an L4B but the fan is going CW and not CCW why is that? Ik it’s an AC motor for the fan.
@tramdr
4 жыл бұрын
Just me, I hate the design of the SSR DC control voltages. The DC control components are connected directly to the 220 mains and are unisolated and unfused. This also seems to be the case in the original one that blew up and is what will happen when one goes south when it is hooked directly to the mains. I would think a redesign using a 12v transformer to drop the voltage and isolate it from direct 220 contact would be in order instead of a resistive / zener dropping circuit connected to the mains. This transformer would provide isolation if something where to go south, plus I would add a fuse to the hot side of the transformer for more protection too. I also think if that's too much, one could use an AC controlled SSR instead of DC. An AC controlled SSR is designed and legal to hook to the mains. IMHO this DC configuration being used is dangerous and illegal. IMHO
@fenderblues1744
6 жыл бұрын
You get some real easy jobs. lol. I thought your voltage was 120v where you are.
@TheRadioShop
6 жыл бұрын
Easy jobs are good. You are correct. The normal house hold voltage is 120 volts here. But all the higher amp stuff uses 220. Like the clothes dryer, water heater, heating unit. And in the shop the AC welder, Air Compressor.
@fenderblues1744
6 жыл бұрын
Thanks. Well I didn't know that. I learn something everyday, especially from you.
@davewilson9345
Жыл бұрын
forsale?
@montygore1200
10 ай бұрын
That delay relay is still too fast. If you can hear the transformer clank you are damaging th ac power switch. You cant even find the rebuild kits for the switches. I had at least 5 kits and 10 switches. I wish I knew you sooner. 73 W5DN
Пікірлер: 73