Mr. R, l recently saw your video on the 811H repair. I hope that you were not charging the customer by the hour because l believe that you went through a lot of labor that was not necessary. I received my novice class license in 1991 and quickly upgraded to extra class. I have been restoring antique radios for quite some time and a must-have is a tube tester which l purchased on eBay. A Precision Model 650. I am glad that l purchased my ameritron in 1992 because it has a hefty open frame relay, not cheap ones they install on a board. The first thing l would have done was to check the tubes. I recently purchased new 811s from dx engineering and found one with a filament to grid short and was sent back. I did not have to go through all the mumbo jumbo that you did. Don't believe that you had to replace the relays and cannot believe you did not have a schematic as you would have known that it is ground grid amplifier. Also, it would be more professional to make a video without the cursing. Best Regards, John AA2MI.
I disagree with you..I think he did everything right..The customer told him the relays were chattering..You troubleshoot the voltages first.And a Variac is a must..You dont take any short cuts and just assume the tubes are bad right away..You have take your time..Your dealing with lethal voltages..Im also licensed ham operator since the 1970's..I respect his work.He sure knows alot more than both of us..This is what he does..73's
I have fixed several of 811H amps like that. ben some changes over the years, some had MOV instead of gas tubes and some had 47 or 51 ohm on grid. I have the AL572 my self. I am running Russia 572/b tubes. I have CETRON in both 811A and 572/B . even got some 811H tubes and marshal 811A tubes. Them china 811A and 572/B have short life. My rod from front snitch to back is a fiber one . Penta still has 572/B tubes. The diagram for that amp is on the MFJ website . PDF download with the manual . after changing lamps a few times I just put LED's in for the meter lamps. 73's
I have a 811H. Haven't used it much. Was using it one night and left it on to cool down. Came back to it and it was dead. I thought it might of dropped a tube. That wasn't it! The amp had a cap go bad in it. The way I found it was to use a old school cap tester. Amp had no hours on it.
Love your work, and a big fan, but as to the statement that antenna tuners are a no no, I disagree. Not only me, but about a 100 years of radio operators will agree, tuners are no more than the PI Network in a transmitter, they tune the amplifier to the load. Personally in the years of Amateur Radio (71) I have used Johnson Matchboxes and done literally hundreds of comparisons using vertical and inverted Vee's, switching between the to making comparisons in signal reports, spectrum readings, impedance losses and gains and etc... I know you want agree, so with that, lets just say, that this is my opinion. 73's Jim
I bet that somewhere in the filament voltage line, there is a micro circuit breaker of some kind. I bet this happened during engineering, and someone had the smart sense to realize if that happened, shorting out the filament could be bad. Kudos for putting in the protection in the circuit.
I'm thinking the tube filaments themselves may act as a fuse when there is a filament to grid short in one of the tubes. You have an AC transformer providing the filament supply being dead shorted from a tube filament right to ground through the affected tube so it makes sense that one of more of the filaments burned up when the tube shorted. The filament wire in 572B tubes is pretty fine wire. When a 3-500Z amp has a filament to grid short, the filament is robust enough to fry the filament transformer if the amp is not shut down in time. In the case of an SB220, a shorted tube takes out the bias zener or the bias diode string if it has the Harbach board. I've fixed a few in my time. I recently repaired an AL572 Ameritron that had the same thing happen to it, one tube internally shorted and it took out the metering protection diode and a couple of other small parts.
Yea. Those relay's suck taking them out. But like you did. Order new and replace them. Good job, Master Luke from 2WR/NB267 or just Trapper. 73 Brother.
OK, I’m fairly inexperienced with this, but when you first had all four tubes in the amplifier, they didn’t light up, one of the tubes had a short from filament to grid, and the grids are grounded, so could that one tube have drawn everything down, causing all four not to light?
Do you happen to have some ideas on why a fairly new Ameritron AL-811 doesn't show any change on the amp meters or a watt metter when turning the plate? I can't tune it since nothing happens with plate and puts out no power. Had the 811s and they looked fine but also switched them out with 572 and no change. Visual inspection inside I see nothing standing out. Ty
What do you recommend for replacement tubes for these? I'm still running 811's in mine, so there will be a day, soon, that they need replaced. So much CHINA junk.
I would recommend the 572B tubes. Your not going to see much in RF output do to the transformer used in these amps but the 572B tubes are more rugged more forgiving. 73 Joe
@@dieseldes6578 Unfortunately all the 572 811a and many other tubes are made in the same factory in china. Bought form china and slap there label on it. It will be hit and miss. From my research the manufacturing process is not the same when making the internals of the tube. Some are good and last a long time and others will be good for a short time and then loose emission. Basically each company that sells the tube can only test them soo far. I have the same amp and have experienced this even with grid and plate current well below spec...
@@dieseldes6578 You can buy new from Penta labs or RF Parts. Both will sell you Chinese tubes but they are burned in "tested" and "matched". Chinese tubes have gotten better over the years but they are what they are. Now if you want to pay the big bucks you can buy "if you can find" NOS USA made Cetron 572B's or Russian Svetlana 572B's. 73 Joe
@@Joe-KN4IFI cheers joe. Just wondering if a 30 year old USA or russian made tube is always better than a new Chinese one. Pays your money makes your choice I suppose. Cheers 73,s
You say tubes are about gone because the grid meter is high. You are supposed to keep your drive low enough to keep it below 120 ma so if it’s peaked out on ssb & it’s buried the scale it’s being over driven.
I have one of these with 3 811’s An Elmer told me the transformer in this amp is designed for 811’s, that it strained its schmooze to run 572’s ? Is this TRUE ? JohnBoyUtah KJ7TBR 😎🇺🇸📡🎙
Those look like the chinese 572b tubes. The old "Russian" svetlana "rf parts" branded tubes were better, if a bit tough to neutralize. Very touchy, but very hot. I never had a lot of luck with the chinese version of the "rf parts" tubes.
ht rest current 1700 v, under load with 600ma, 1500v ht, current and ht = output @62 % so to me it functions as it would at 1500v.... now bump the ht to 2200 v under load and the TUBES will work as intended. baseline 650 to 700 watt peak! vs 2200v - 850 watt! im sure you know what you are doing but also sure all is not what it seems.
Well, I learned a valuable lesson on this one. I finally realized you build Linears for Concrete Brains. Ameritron on 11 Meters? Of course it isn't designed to work on 11 Meters. That's because Concrete Brais ARE NOT supposed to use Linears! I lost ALL respect for you. Linears are ILLEGAL on Concrete Brain band. Sad that you resort to building Linears for CBers. FYI: You obviously don't know your Tube Linears. 811A / 572B tubes require 10 Volts between Filament and Grid. If you ground the Grid, you have to float the Filaments. That's why they add 6 Diodes to the Center Tap of the Filament winding, to bias the Filaments 4 volts higher. Grounded Grid Linears are notorious for Flashover. One reason: Floating the Filaments. Then, they have to add Gas Dischrage Tubes (GDT's) to the Filament bus. I have a Gonset 101. Grounded CT on the Filaments, -4.0 VDC on the Grids. Cutoff is a -100 VDC supply. Same as Collins used, LoudenBoomer, etc. I have yet to hear of a Linear with a grounded Filament CT getting flashover.
By far the worst case of troubleshooting I have ever seen. Take my word for it, I have been servicing simple AM radios to 200K plus digital organs. I never changed out any parts until I could verify the problem. Never jump in and shotgun anything. As always IMHO
I don't know how it's even still a debate. The guy that designed the circuit used in most of your 572B and 3-500Z amps even said it... GROUND THE GRIDS. 🤷
Mr. R, l recently saw your video on the 811H repair. I hope that you were not charging the customer by the hour because l believe that you went through a lot of labor that was not necessary. I received my novice class license in 1991 and quickly upgraded to extra class. I have been restoring antique radios for quite some time and a must-have is a tube tester which l purchased on eBay. A Precision Model 650.
I am glad that l purchased my ameritron in 1992 because it has a hefty open frame relay, not cheap ones they install on a board. The first thing l would have done was to check the tubes. I recently purchased new 811s from dx engineering and found one with a filament to grid short and was sent back. I did not have to go through all the mumbo jumbo that you did. Don't believe that you had to replace the relays and cannot believe you did not have a schematic as you would have known that it is ground grid amplifier. Also, it would be more professional to make a video without the cursing.
Best Regards,
John AA2MI.
I disagree with you..I think he did everything right..The customer told him the relays were chattering..You troubleshoot the voltages first.And a Variac is a must..You dont take any short cuts and just assume the tubes are bad right away..You have take your time..Your dealing with lethal voltages..Im also licensed ham operator since the 1970's..I respect his work.He sure knows alot more than both of us..This is what he does..73's
Real great video and great learning for me. Just loved this. Glad you take the time to share this and extra entertainment. Thanks a million
I love BBI and learning has occurred. Thank you for teaching!
I have fixed several of 811H amps like that. ben some changes over the years, some had MOV instead of gas tubes and some had 47 or 51 ohm on grid. I have the AL572 my self. I am running Russia 572/b tubes. I have CETRON in both 811A and 572/B . even got some 811H tubes and marshal 811A tubes. Them china 811A and 572/B have short life. My rod from front snitch to back is a fiber one . Penta still has 572/B tubes. The diagram for that amp is on the MFJ website . PDF download with the manual . after changing lamps a few times I just put LED's in for the meter lamps. 73's
We appreciate you brother 73s from elvisland
I have a 811H. Haven't used it much. Was using it one night and left it on to cool down. Came back to it and it was dead. I thought it might of dropped a tube. That wasn't it! The amp had a cap go bad in it. The way I found it was to use a old school cap tester.
Amp had no hours on it.
Nice video well done. Remember this video was made as a teaching tool.
Well done Mr. BBI, that amp is good for another 100K miles.
this is the first bbi tube video I have watched, and I couldn't make it past the 10 minute mark. best of luck with that
Love your work, and a big fan, but as to the statement that antenna tuners are a no no, I disagree. Not only me, but about a 100 years of radio operators will agree, tuners are no more than the PI Network in a transmitter, they tune the amplifier to the load. Personally in the years of Amateur Radio (71) I have used Johnson Matchboxes and done literally hundreds of comparisons using vertical and inverted Vee's, switching between the to making comparisons in signal reports, spectrum readings, impedance losses and gains and etc... I know you want agree, so with that, lets just say, that this is my opinion. 73's Jim
My phased verticals cannot survive without a good antenna tuner since I operate on all bands 1.8 Mhz through 54.0 Mhz....Layne AE1N
I bet that somewhere in the filament voltage line, there is a micro circuit breaker of some kind. I bet this happened during engineering, and someone had the smart sense to realize if that happened, shorting out the filament could be bad. Kudos for putting in the protection in the circuit.
I'm thinking the tube filaments themselves may act as a fuse when there is a filament to grid short in one of the tubes. You have an AC transformer providing the filament supply being dead shorted from a tube filament right to ground through the affected tube so it makes sense that one of more of the filaments burned up when the tube shorted. The filament wire in 572B tubes is pretty fine wire. When a 3-500Z amp has a filament to grid short, the filament is robust enough to fry the filament transformer if the amp is not shut down in time. In the case of an SB220, a shorted tube takes out the bias zener or the bias diode string if it has the Harbach board. I've fixed a few in my time. I recently repaired an AL572 Ameritron that had the same thing happen to it, one tube internally shorted and it took out the metering protection diode and a couple of other small parts.
Ótimo trabalho gualidade total bazuka Foz do Iguaçu pr Brasil 🇧🇷🦈 73
Yea. Those relay's suck taking them out. But like you did. Order new and replace them. Good job, Master Luke from 2WR/NB267 or just Trapper. 73 Brother.
Mr. Carlson has a desoldering station.
OK, I’m fairly inexperienced with this, but when you first had all four tubes in the amplifier, they didn’t light up, one of the tubes had a short from filament to grid, and the grids are grounded, so could that one tube have drawn everything down, causing all four not to light?
Do you happen to have some ideas on why a fairly new Ameritron AL-811 doesn't show any change on the amp meters or a watt metter when turning the plate? I can't tune it since nothing happens with plate and puts out no power. Had the 811s and they looked fine but also switched them out with 572 and no change. Visual inspection inside I see nothing standing out. Ty
Does the bias value need to change when you switch from the 811’s to 572’s ?
Very nicely done Sir
If you've got a short it's path of least resistance so no current to good tubes all voltage to short.
The one time I had a tube go it blew both fuses. Found bad tube by replacing them one at a time. I also had to replace the D-1 diode
I have a VL-1000 quadra amp do you have any experience working on them.
Tinha um linear desse ele me deu um prejuízo de 4 tubos,instalei 2 gi7bt.esse linear é problemático de mais.
Do you suppose the sound the operator heard was the tubes going into oscillation?
Greetings from Denmark
🇩🇰 🖖 🇩 🇰 🖖 🇩🇰 ♥️ 👍 👍 👍
I got the 1200watt 811H
Any mods for that??
So one shorted grid to ground tube would cause none of the filaments to light up? That's crazy
Sorry to hear about 700 bucks for transistor’s hope you can keep going in this inflationary time!
What do you recommend for replacement tubes for these? I'm still running 811's in mine, so there will be a day, soon, that they need replaced. So much CHINA junk.
I would recommend the 572B tubes. Your not going to see much in RF output do to the transformer used in these amps but the 572B tubes are more rugged more forgiving. 73 Joe
@@Joe-KN4IFI any particular brand to go with, or avoid using? Penta labs?
@@dieseldes6578 Unfortunately all the 572 811a and many other tubes are made in the same factory in china. Bought form china and slap there label on it. It will be hit and miss. From my research the manufacturing process is not the same when making the internals of the tube. Some are good and last a long time and others will be good for a short time and then loose emission. Basically each company that sells the tube can only test them soo far. I have the same amp and have experienced this even with grid and plate current well below spec...
@@dieseldes6578 You can buy new from Penta labs or RF Parts. Both will sell you Chinese tubes but they are burned in "tested" and "matched". Chinese tubes have gotten better over the years but they are what they are. Now if you want to pay the big bucks you can buy "if you can find" NOS USA made Cetron 572B's or Russian Svetlana 572B's. 73 Joe
@@Joe-KN4IFI cheers joe. Just wondering if a 30 year old USA or russian made tube is always better than a new Chinese one. Pays your money makes your choice I suppose. Cheers 73,s
Why not use sockets so if they go bad they can be changed easily?
You say tubes are about gone because the grid meter is high. You are supposed to keep your drive low enough to keep it below 120 ma so if it’s peaked out on ssb & it’s buried the scale it’s being over driven.
I think you're confusing plate Amp meter and Grid meter.
The worst thing you can do to a tube is run the filaments out of spec.
Relays could not be mounted with socket’s?????
I have one of these with 3 811’s An Elmer told me the transformer in this amp is designed for 811’s, that it strained its schmooze to run 572’s ? Is this TRUE ? JohnBoyUtah KJ7TBR 😎🇺🇸📡🎙
Why are you ignoring the pegged grid current meter? ??
Those look like the chinese 572b tubes. The old "Russian" svetlana "rf parts" branded tubes were better, if a bit tough to neutralize. Very touchy, but very hot. I never had a lot of luck with the chinese version of the "rf parts" tubes.
ht rest current 1700 v, under load with 600ma, 1500v ht, current and ht = output @62 % so to me it functions as it would at 1500v.... now bump the ht to 2200 v under load and the TUBES will work as intended. baseline 650 to 700 watt peak! vs 2200v - 850 watt!
im sure you know what you are doing but also sure all is not what it seems.
What should this do with 4 new tubes?
700
@@vsmichael1 thanks
When mfj bought Ameritron quality went down, on these amps.
Have a pair of brand new in the original box never used centron 572bs for sale if anyone is interested.
🤣😂😅😆
I have a Heathkit sb200 fitted 2 gi6b tubes same as Gi7b much better output 1000 watts
Well, I learned a valuable lesson on this one. I finally realized you build Linears for Concrete Brains. Ameritron on 11 Meters? Of course it isn't designed to work on 11 Meters. That's because Concrete Brais ARE NOT supposed to use Linears! I lost ALL respect for you. Linears are ILLEGAL on Concrete Brain band. Sad that you resort to building Linears for CBers.
FYI: You obviously don't know your Tube Linears. 811A / 572B tubes require 10 Volts between Filament and Grid. If you ground the Grid, you have to float the Filaments. That's why they add 6 Diodes to the Center Tap of the Filament winding, to bias the Filaments 4 volts higher. Grounded Grid Linears are notorious for Flashover. One reason: Floating the Filaments. Then, they have to add Gas Dischrage Tubes (GDT's) to the Filament bus. I have a Gonset 101. Grounded CT on the Filaments, -4.0 VDC on the Grids. Cutoff is a -100 VDC supply. Same as Collins used, LoudenBoomer, etc. I have yet to hear of a Linear with a grounded Filament CT getting flashover.
By far the worst case of troubleshooting I have ever seen. Take my word for it, I have been servicing simple AM radios to 200K plus digital organs. I never changed out any parts until I could verify the problem. Never jump in and shotgun anything. As always IMHO
I don't know how it's even still a debate. The guy that designed the circuit used in most of your 572B and 3-500Z amps even said it... GROUND THE GRIDS. 🤷
did bbi say you shouldn't?
@@Russ-nf9tv NO. But people will still argue you shouldn't. 🤷
Point being... Luke's spot-on.
@@TheTreegodfather he said 2 dumb things and I turned the video off, so I wasn't certain if that was a third. Thanks!