Dr. Kemp, By providing this info, you provide a noble service that, in the end, keeps Hammonds alive for all; even for those that can't afford a repair or get to a technician. It would be a shame to see any Hammond go to waste. I believe the tech industry should be based on expertise as opposed to secrets, also; so thanks for keeping everybody honest!
blessings to you my brother for posting these videos. I don't have a leslie tech in my area so your videos are so valuable. keep them coming. bless you again
Hello Ryan. Yes - I am at it more now than ever before. I have so much work to do that I am overwhelmed. I have to come to my shop everyday to knock down another amp. It takes a day to rebuild one of these things along with all the other stuff that one has to do in the shop and in life. But I am enjoying it. I just rebuilt two 22H Amplifiers. I am waiting on an order of wire wound resisters that attache to the relay switch. I'll also replace the old relays. Glad you're enjoying the videos.
I love rebuilding those old amps. :) I've rebuilt several, including 122's, 21H's and a 31H. There's a Leslie 50C series I'm getting for free that I'm hoping to convert to use with my RT-3. That will be a fun project!
hi doctor. I've been searching for a video on how to replace a power cord on a j122. The cord shorted out in the middle, but its old and dried up so just reattaching the cord at the split won't fix it long term. I need to figure out how to open up the chasis and replace the whole cord. Any help is appreciated.
Sounds like you need to check your relay as well as the lower motor of your Leslie. Also make sure that the 12AU7 tube on the left is good on both sides. This tube can have one good and one bad side. So switch the 12AU7 tubes around and see what happens then.
Hello Dr Kemp, a friend gave me a 147 amp that was converted to 122 specs. The amp sounds great but i cant switch the speed of rotation of the leslie. The horn is stuck on fast and the lower rotor is kind stuck in between fast and slow... weirdly. I have check the fuse, its fine, Is it just a bad relay you think?
That's cool TWP. I had two 50C's that I sold on ebay and bought a couple of 47's to rebuild instead. The 47's are easier to work with in that you can wire an organ directly to match this amp without a kit. The 50C which is of the 251 family requires a kit (a 4-H kit I believe) to operate - which is not bad to connect to a RT-3 if you have the wiring instructions. So will you be converting the 50C to a 47 or using a kit like the 4-H box?
Hello Mr. Kemp, I am the new proud owner of a beat-up leslie 122 and i am planning restore it. I am a novice to electronics and i wanted at least to check my resistors and capacitors but I read alot of different oppinions about the dangers of capacitors. Some say they can hold lethal amount of current for days and other people will say that after 4-5 seconds you are good to go to manipulate them. I would like to have your oppinion on that subject if it is possible. Thank you!
I agree with you Brother Pfeiler 100% and have added this to my description above: A live Leslie amplifier can produce over 400 volts of electricity. Even when unplugged, the amplifier will carry residual electrical charge. Therefore, serious injury or even death can result from making contact with a Leslie amplifier. Novices should therefore receive proper training in electronics prior to attempting to work on any tube amplifier.
Dr Kemp, Could i ask you In the 122 147 251 etc.almost all 1/2 watt resistors are 10% here in U/K you have got to search for them do you have any reservations replacing them with 5 % they are so much easier to acquire..your videos are so very helpful to the novice Thank you so much.....Brian.
Brian, It is OK to use resistors with 5% tolerance. They work the same as those with 10% tolerance. They just allow for less deviation from the base level.
I have a Leslie 145 (shorter version of the 122, same amp) that has an audio "pop" when I change speeds. I'm assuming its a cap... do you have any ideas which to check?
Robert - The two .1 caps that sit on the motor sockets are referred to as suppression capacitors. There job is to suppress the pop when the relay is activated. New caps will eliminate such a pop.
Thanks for these videos! I am working on a 122 Leslie hooked to a B-3. I have 2 issues maybe you can give tips? 1. Fast speed only works after a few minutes of "warm up". Until then, it is only "half-fast" I'm assuming some capacitor? I put in all new tubes thinking maybe it was the OC3, but that didn't help. It does work normally after a few minutes of warming up. Both fast motors act the same, so I'm thining it has to do with the amp supplying voltage. 2. A slight 60Hz hum (I've heard a lot worse). But what might I check to reduce the 60Hz hum (ground hum). Thanks for any tips you might have.
If there is a hum - I always check my Leslie cable first to make sure it is in good shape. I will try another cable to try to isolate that as the issue. Another thing that can cause hums is the Preamp in the organ. So to isolate that - I change out the Leslie amplifier and see if I get the same hum. If I don't, I know that it was the other Leslie amp. If the hum continues, then I would begin to look at the AO 28 preamp - more specifically the multi can capacitor.
I have the same problem with the fast speed taking about 10 minutes before it works and once it's warmed up it works. meantime it it just goes a little faster than the slow speed.
Thank you so very much John. I now own a Blue ESR meter. You are correct - that is the only way to accurately evaluate the integrity of a capacitor. I was taught to use a multimeter to check them. But have found since purchasing my ESR meter that a multimeter can test the cap as bad while the ESR meter reveals otherwise. I have now had my ESR meter for several months and will use it from now on. Thanks once again.
Never touch the ends (the part that you connect) of the caps and resistors with your hands. Clip out the old ones and pick them up and remove them with you needle nose plyers. Safety First!!
Dr. Kemp, By providing this info, you provide a noble service that, in the end, keeps Hammonds alive for all; even for those that can't afford a repair or get to a technician. It would be a shame to see any Hammond go to waste. I believe the tech industry should be based on expertise as opposed to secrets, also; so thanks for keeping everybody honest!
blessings to you my brother for posting these videos. I don't have a leslie tech in my area so your videos are so valuable. keep them coming. bless you again
Hello Ryan. Yes - I am at it more now than ever before. I have so much work to do that I am overwhelmed. I have to come to my shop everyday to knock down another amp. It takes a day to rebuild one of these things along with all the other stuff that one has to do in the shop and in life. But I am enjoying it. I just rebuilt two 22H Amplifiers. I am waiting on an order of wire wound resisters that attache to the relay switch. I'll also replace the old relays. Glad you're enjoying the videos.
I love rebuilding those old amps. :) I've rebuilt several, including 122's, 21H's and a 31H. There's a Leslie 50C series I'm getting for free that I'm hoping to convert to use with my RT-3. That will be a fun project!
question....who has replaced the original leslie amps with solid state amps? and what has been the result??
hi doctor. I've been searching for a video on how to replace a power cord on a j122. The cord shorted out in the middle, but its old and dried up so just reattaching the cord at the split won't fix it long term. I need to figure out how to open up the chasis and replace the whole cord. Any help is appreciated.
Sounds like you need to check your relay as well as the lower motor of your Leslie. Also make sure that the 12AU7 tube on the left is good on both sides. This tube can have one good and one bad side. So switch the 12AU7 tubes around and see what happens then.
Hello Dr Kemp, a friend gave me a 147 amp that was converted to 122 specs. The amp sounds great but i cant switch the speed of rotation of the leslie. The horn is stuck on fast and the lower rotor is kind stuck in between fast and slow... weirdly. I have check the fuse, its fine, Is it just a bad relay you think?
Just to be safe, what would you say is the best way to discharge that high voltage capacitor?
You can use a jumper to connect each pole to the negative pole on the can.
That's cool TWP. I had two 50C's that I sold on ebay and bought a couple of 47's to rebuild instead. The 47's are easier to work with in that you can wire an organ directly to match this amp without a kit. The 50C which is of the 251 family requires a kit (a 4-H kit I believe) to operate - which is not bad to connect to a RT-3 if you have the wiring instructions. So will you be converting the 50C to a 47 or using a kit like the 4-H box?
Hello Mr. Kemp,
I am the new proud owner of a beat-up leslie 122 and i am planning restore it. I am a novice to electronics and i wanted at least to check my resistors and capacitors but I read alot of different oppinions about the dangers of capacitors. Some say they can hold lethal amount of current for days and other people will say that after 4-5 seconds you are good to go to manipulate them. I would like to have your oppinion on that subject if it is possible. Thank you!
I agree with you Brother Pfeiler 100% and have added this to my description above: A live Leslie amplifier can produce over 400 volts of electricity. Even when unplugged, the amplifier will carry residual electrical charge. Therefore, serious injury or even death can result from making contact with a Leslie amplifier. Novices should therefore receive proper training in electronics prior to attempting to work on any tube amplifier.
Dr Kemp, Could i ask you In the 122 147 251 etc.almost all 1/2 watt resistors are 10%
here in U/K you have got to search for them do you have any reservations replacing them
with 5 % they are so much easier to acquire..your videos are so very helpful to the novice
Thank you so much.....Brian.
Brian,
It is OK to use resistors with 5% tolerance. They work the same as those with 10% tolerance. They just allow for less deviation from the base level.
I have a Leslie 145 (shorter version of the 122, same amp) that has an audio "pop" when I change speeds. I'm assuming its a cap... do you have any ideas which to check?
Robert - The two .1 caps that sit on the motor sockets are referred to as suppression capacitors. There job is to suppress the pop when the relay is activated. New caps will eliminate such a pop.
+Dr. Arthur D. Kemp Thank you very much!!! I'll replace them.
Beautiful work!
Thanks Rob
Thanks for these videos! I am working on a 122 Leslie hooked to a B-3. I have 2 issues maybe you can give tips? 1. Fast speed only works after a few minutes of "warm up". Until then, it is only "half-fast" I'm assuming some capacitor? I put in all new tubes thinking maybe it was the OC3, but that didn't help. It does work normally after a few minutes of warming up. Both fast motors act the same, so I'm thining it has to do with the amp supplying voltage. 2. A slight 60Hz hum (I've heard a lot worse). But what might I check to reduce the 60Hz hum (ground hum). Thanks for any tips you might have.
If there is a hum - I always check my Leslie cable first to make sure it is in good shape. I will try another cable to try to isolate that as the issue. Another thing that can cause hums is the Preamp in the organ. So to isolate that - I change out the Leslie amplifier and see if I get the same hum. If I don't, I know that it was the other Leslie amp. If the hum continues, then I would begin to look at the AO 28 preamp - more specifically the multi can capacitor.
I have the same problem with the fast speed taking about 10 minutes before it works and once it's warmed up it works. meantime it it just goes a little faster than the slow speed.
If it's a 122 or 147 assess the OC3, the 12AU7, the Can Capacitor and then the resistors - especially those at the 12AU7 and near the OC3.
That's wonderful Brujun. I pray that you are able to resolve many issues via my video instruction. Blessings!!
However Doc, the most important message should be discussed first: Newbees keep off your fingers from tube amps: HIGH VOLTAGE UNDER THE HOOD!!!
I need to send my amp to you lol i need your contact info
I will contact you David.
The way to test capacitors with a fuke meter is totally wrong
you need a ESR cap meter to measure capacitance and leakage
Thank you so very much John. I now own a Blue ESR meter. You are correct - that is the only way to accurately evaluate the integrity of a capacitor. I was taught to use a multimeter to check them. But have found since purchasing my ESR meter that a multimeter can test the cap as bad while the ESR meter reveals otherwise. I have now had my ESR meter for several months and will use it from now on. Thanks once again.
Never touch the ends (the part that you connect) of the caps and resistors with your hands. Clip out the old ones and pick them up and remove them with you needle nose plyers. Safety First!!
Yeah, that's not a box wrench, that's a nut driver.
Thanks - I appreciate the correction.