1960 Lesmann 500 Accordio-organ Pat.Pend

[rafe]

I swear i felt the dog-house so I pulled out the chassis to check the Caps! ....Nope it's the later models with the dog-house .....I could have done the work with it in the cabinet (oh well) no big deal you say? Not a real big deal but it's not easy access to the nuts that are not fixed to the chassis same thing as with the Epiphone only more so. This thing is a beast, The PT is Marshall territory, OT is hefty too, It has newer than 1960 Sprague filter caps They are numbered TVA1906 (19th week of 2006?) I don't know if that is the code or not....It works but sounds ??Flubby?? too much bass and all the pots are not scratchy they whoosh when you move them.....I have one obvious cap that has to go it's a wax cap......other than that remains to be seen.....It's out to my bench post photo's later today ....

[SEL49]

They are numbered TVA1906 (19th week of 2006?) I don't know if that is the code or not

That's not a date code. TVA#### is the part number for the Sprague Atom series caps.

[rafe]

thanks sel49

[bmccowan]

Hey Rafe,
I think it'd be useful if you reposted the discussions we had on the Lesmann in the Epiphone thread, in this thread.
And yes they are beasts. I bought mine shortly before I had a medical event that is limiting what I am supposed to lift. On mine I think I will disconnect the Accordion interface and mod the mic channel to an early Fender Pro type circuit. I understand it is very similar. And then I will sell it to someone who can lift it.
I'd gladly get it into the hands of a Lesmann accordion player, but they seem to have gone into the Accordion Witness Protection Program.

[rafe]

re are some great links from the thread on the 1961 Epiphone Century by Bmccowan; The more I discover about the epi the more gratitude I have for finding this EPI there are some videos of the 12" speaker and ax7 varieties but I've yet to find any 15" 6eu7's videos .....I don't think there are many of these around??? anyway here are the links to the Lesmann;
https://reverb.com/item/59340640-lesmann-imperial-500p-accordio-organ-amplifier-1966And a project blog with some interesting info:https://judyboxamp.blogspot.com/2017/04/the-lesmann-amplifier-project.htmlAnd discussion threads:https://www.tdpri.com/threads/psa-an-oddball-amp-you-should-not-dismiss.889958/https://bb.steelguitarforum.com/viewtopic.php?t=318830&sid=82453800b79302bb2f4a6a11bb105512https://www.tdpri.com/threads/my-new-fargen-lesmann-tweed-bandmaster.1152581/https://surfguitar101.com/forums/topic/18865/

[bmccowan]

Thanks Rafe - and here is the schematic I have. I have not checked it yet against my Lesmann. The mic channel is pretty darn close to a 5D5 Pro.

[rafe]

I believe the 500P is revised a good bit from the Accordia-organ 500 ....that schematic is from 66 and my amp is a 60. That said it may be helpful. I pulled the chassis and have it on the bench I replaced the wax .022 with an old Sprague and it didn't go well ....it was squealing and motor boating after I did. I am hoping it's just that cap and not something dislodged under the board. I have a new cap i'll do that tomorrow.....Meanwhile....Someone in the past recapped this amp .....and I don't approve they have 2-80uf 450v and 2-40uf 450v sprauges that take up a lot of real estate on the board  I have 40uf and 22uf 500v's here. The 500P schematic calls for 30's and a 10 but here is a photo of the one with the doghouse  and there are more electolytiics inside the amp (see photos in the judybox link) I am wondering if the doghouse is a later mod....Also see why it's good practice to expose the values in your repairs or builds ....out of all the caps I see one 20uf & one 30uf

[bmccowan]

I pulled the chassis and have it on the bench I replaced the wax .022 with an old Sprague and it didn't go well ....it was squealing and motor boating after I did.

Was it squealing and motor boating before you replaced the cap?
From reading the descriptions from owners, it does seem that the 500P was changed quite a bit from the 500 - especially the power rail/filter caps. And if you have 2 80uf caps in your amp, check to see if they are in series to provide 40uf at a higher voltage rating. Fender did that in quite a few of their larger amps.
I suggest that since there does not seem to be a 500 schematic out there, before you go further, use the 500P schematic as a guide and document the differences. Do you use Express or Jschem? They are easy to learn and once you do you'll wonder why you waited. And, you'll be doing a kind service to anyone else out their with a 500.

[rafe]

....I was almost finished with the last post and "POOF" it was gone. I type this reply and was almost finished and (EFFEN GONE) let me repeat. No, it didn't squeal and motorboat. I am hoping it is just a bad replacement cap. I am leaning towards lifting the board to make sure I didn't drive the wire out of the bottom of the eyelet so I removed the two 80uf 450's......The previous work was not appealing to me, my guess is that there were 3 caps there on the eyelet board a 10uf and 2-30uf 450v caps like on the 500P schematic, side by side just a sight to see. But the recapper put the 40uf in (a big blue Sprague) like a size 12 foot in a size 10 shoe. well, the 80uf 450v huge blue Sprague's were mounted sideways on top of the 40uf and zip tied together to the pot ground wire (for stability)......so I pulled them out, a must if I lift the board as they were in the way. There was some speculation (Uncle Doug) as to why they used a 4amp fuse......maybe the initial jolt on the caps?? soooooo any thought on the 22uf 500v 40uf 500v ? going from 30 to 80 is a pretty big jump, with out knowing what is under the board makes it hard to tell if it is in series. I am not really good with schematics. but not having one sucks and I am not really good with an amp that has had values changed like this ....But if I were a gambler, I'd lean towards the value of the filter caps on that 500p schematic //o-o\\

[rafe]

 it's not my day

[bmccowan]

....I was almost finished with the last post and "POOF" it was gone. I type this reply and was almost finished and (EFFEN GONE) let me repeat. No, it didn't squeal and motorboat. I am hoping it is just a bad replacement cap. I am leaning towards lifting the board to make sure I didn't drive the wire out of the bottom of the eyelet so I removed the two 80uf 450's......The previous work was not appealing to me, my guess is that there were 3 caps there on the eyelet board a 10uf and 2-30uf 450v caps like on the 500P schematic, side by side just a sight to see. But the recapper put the 40uf in (a big blue Sprague) like a size 12 foot in a size 10 shoe. well, the 80uf 450v huge blue Sprague's were mounted sideways on top of the 40uf and zip tied together to the pot ground wire (for stability)......so I pulled them out, a must if I lift the board as they were in the way. There was some speculation (Uncle Doug) as to why they used a 4amp fuse......maybe the initial jolt on the caps?? soooooo any thought on the 22uf 500v 40uf 500v ? going from 30 to 80 is a pretty big jump, with out knowing what is under the board makes it hard to tell if it is in series. I am not really good with schematics. but not having one sucks and I am not really good with an amp that has had values changed like this ....But if I were a gambler, I'd lean towards the value of the filter caps on that 500p schematic //o-o\\

4 amp fuse - could be due to the additional current draw of the connected electronic accordion
The mess of additional filter caps - I also would have removed those - clearly a sloppy attempt to fix a problem.
Squeal and motorboat - likely totally failed capacitors or a ground is loose/broken. Trying to band-aid this amp is not a good idea IMO. It seems there is a history of problems that will likely stay unknown. No need to replicate that. So the best course is to treat it as a rebuild. You are not going to become Weird Al Yankavic so a standard Fender style power rail should be fine for a conversion to a guitar amp.
I agree that not having a schematic sucks. But not being good with schematics sucks too. The reality is that you are ahead of the game with a schematic from a later model - the basic circuit structure is likely not too different. You also have schematics from the tweed Fender Pro, which by all accounts is very similar for the mic channel.
Nobody is good with schematics until they learn them. We are used to thinking of diagrams as physical roadmaps. Schematics are simply maps of the electronics. Start to work with them and a light bulb will go off at some point. And then you have a great tool. Until then, a project like the one in front of you is a royal PIA.
If you make a copy of that 500P schematic and start marking the similarities and differences - you will learn a lot about schematics - and the amp.
Sorry to go on and on and on and on (Randy Newman) but I feel for those here who struggle with build or rebuild projects and resist becoming comfortable with schematics.

[rafe]

I sometimes think the filament is gone in the lightbulb when it comes to schematics ...... I haven't given up on them through and have somewhat of a lot of the concepts .... I went out today and replaced the 4 electrolytic's and the .022 cleared things up to a great extent.... It still wanted to squeal just a little when moving the treble pot full and lightly motorboated when bass was full up ... the only tube that wasn't USA was a J/J and I wiggled it and it made some noise so I pulled it ..... I had a NOS rca 12au7 and it cleared it right up..... The J/J was not marked and I suspect they used a 12ax7 it was the phase converter...... I have a single coil cheapo pick-up on a 4" lead so it made some noise. I'll bring out a guitar later , like tomorrow later ..... I think I'm right on the values .... 2 F&T-22uf -500v and 2 MOD 40uf-500v Looks a lot better too .... I'll post a follow up ..... I have photos but I can't load them I'll have to e-mail them to my brother and have Him e-mail them to me

[rafe]

Before

[rafe]

after

[rafe]

Ran the tele through it today 8ohm 2x12 peavey closed back ....nice and quiet. There is another input under the chassis...it sounds best.  3 separate volumes and a bass and treble It's not as loud as it was through the 15' Westinghouse alnico .....I'll hook that back up and see if that helps. I don't like the gauge of the 3 wire they used the lightest I have ever seen Yellow is ground then you have blue and brown ......It has a weird set-up PT  filament transformer and another all inter-connected then another one on the odd input .....I'm going to rewire it the same way .........I wish there was a genius in the neighbor hood ......,I may list it on Chicago Polka players anonymous.........I don't think it was molested other than what I have or will undo

[Willabe]

......,I may list it on Chicago Polka players anonymous.........

Might have better luck listing it in Milwaukee Wis. 

[mresistor]

Leonardo and Mona   

[rafe]

......,I may list it on Chicago Polka players anonymous.........

Might have better luck listing it in Milwaukee Wis. 

Well................that's what I meant,  but it came out Chicago...I have no idea why......It's like when you hear the buzzer when you are closing the locked car door and when there are 5''s left to go and you realize "the BUZZER"  keys are in the ignition but you close it anyway ....time   and time again  ........

[Willabe]

They Polka in Chicago. A lot of Polish and Germans. 

[rafe]

more has been revealed ....Here are two pictures of mine and one from online......Mine has caps on the board ....I believe the other has a doghouse with the electrolytics ......those two empty sockets on mine which are empty appear to be for cap cans.....I think they are for the accordion 4 pin input ...But I am going to check

[bmccowan]

Hey Rafe,
So it appears that there are at least 3 versions of the Lesmann. I arrived home where the amp lives and opened her up. Pics are attached.
Some info that relates to your comments/questions:
 - My 500p is consistent with the schematic I had attached earlier.
 - There are no cap cans.
 - There is a doghouse. The dogs were growling so I have not gone in there yet - but I suspect consistency with the schematic.
 - There are two filter caps on a board along with two diodes. They are high capacitance (1000mfd)/low voltage (17v) They connect to the accordion interface, which is powered by a dedicated coil in the PT.
 - The additional input on the underside of the chassis that you mentioned is for the expression pedal - I suspect the same for yours. It connects to 1/2 of the last preamp tube upstream of the phase inverter.
 - The two mic inputs feed 1/2 of the first preamp tube (marked v6 on the schematic)
 - Next stop are the vol and tone pots feeding 1/2 of the second preamp tube (v5)
 - It's then on to the phase inverter
 - The accordion circuit includes 1/2 of V6, 1/2 of V5, and all of v7 and v8.
 - Eliminating the accordion circuit leaves the amp with a pretty standard Fender tweed circuit incorporating pieces of Pro 5D5 and Super 5F4. The accordion circuit could be rewired into a second guitar channel, but I likely will choose to not do so.
 

[rafe]

I believe you will find that the input underneath is the organ input ....Mine has a lot of differences than yours ...the one I truly regret is the Pre tolex ....it appears to be paper backed thin brittle plastic ....low quality compared to what you have ....same grill cloth though; I redid the three way ,it had neutral to the fuse tip and has a separate filament transformer....so neutral y's to both transformers and hot goes to fuse tip to switch  then y's to both transformers the 2 sockets on mine were never caps as i thought, they are octal sockets and come off a leg of the filament tranny through a diode to pin 5 of the first octal to pin 8 of the second octal; then from pin 5 of the second octal to pin 5 of the 5 pin input (there is no continuety across the pins on octal 2) both octals are grounded on pin ones.....Maybe there was something in them at some time ...but they don't seem important for my usage ???? I think the 500 lesmann has a lot of different iterations from inception to its demise. I don't think the 500p 1966 has more than a few similarities to the 1960 ....I'm still hoping for a schematic.....

[bmccowan]

I believe you will find that the input underneath is the organ input

Not on this amp - the accordion (or what Lesmann called the Accordio-organ), plugs into a 6 pin connector which feeds 1/2 of the first preamp tube. The pedal connects to the 1/4" jack under the chassis and connects to 1/2 of the second preamp tube. One could certainly plug a guitar into that jack and have an operating amp similar to a Supro Thunderbolt - not so bad.
You, I, and many others have searched for that earlier 500 schematic. I think you may want to bite the bullet and sketch one out. Folks here will help.
Seen this? https://www.tdpri.com/threads/poor-mans-tweed.719919/

[rafe]

That one in the old forum is newer? or older? than mine .....has the cap can visible ..I will likely Tweed the cabinet at some point !.....I have a more pressing matter right now, that can't be good   I checked the ma on the power tubes and the needle fluctuates between  40-60 on one tube 20ish to 100 on the other and follows the tubes.....Voltages on ggl6's are-410 0n plates, 21v on cathodes, grids #1(Fluc.) .35-.45, .040-.070 both +....
G2-293v
Point me in the right direction, Tubes?? I'll start looking for bad resistors . I'm thinking this is the motoboating I was hearing that went away after the caps were replaced but is still there just not audible?

[bmccowan]

Well - tubes should always be the first suspects. Do you have spares?
Have you checked voltage at tube sockets with only the rectifier in place? And then with tubes?
Maybe others can offer better advice. You have an amp in front of you, and no schematic. We have no amp in front of us, and no schematic. Not much to go on. If you don't want to sketch out the circuit, voltage at the tube sockets and some good photos might help.

[rafe]

I have 6l6gc not b's ....I will test voltages with tubes out tomorrow, Has had some work done ,It looks like mostly caps but have no way of knowing if circuit was changed ......Got to run ....i'll see what I can find out tomorrow

[bmccowan]

no worries on the differing suffixes on the 6L6s.

[rafe]

Years ago I made a probe with an octal base and a NOS Simpson Ma meter it was always  dependable ....I put a set of tubes I saved and they both reacted the same as each other ....both fluctuated between 22 and 58 I'm thinking it's the meter acting up, the amp sounds good ......but not deafening and Tone stack is somewhat lacking ....I took voltages with the tubes out I'll post them later today

[rafe]

No tubes
6L6
pins 3 537
Pins 5 538
12au7 Phase inverter
pin 1  530
pin 2  7.72
pin 6  537
pin 7  6.4
pin 8 3.6
12 ax7's  all 3are 534 0n pin 1 /  530, 533, 541 in order on pin 6 3,75 on pin 7 of last tube

[Willabe]

Put the tubes back in, those 500+dcv are too much for the filter caps.

[rafe]

What do you say to a capacitor, if they can't take a jolt??  They were back in when I posted the voltages, It's runs quiet .....I am going to check the resistor's tolerances and caps for dc leakage. I cleaned the pots and they cleared up good, but there is a spot on a couple that makes a funny sound if all checks out it goes back in the box and I'll see how it sounds through the 15" alnico

[bmccowan]

Willabe knows better than me, so I would defer to his judgment. But, have you rechecked the voltages after putting the tubes back in? An unknown with an amp that also powers an electronic accordion or organ, is how much current that instrument is going to draw. You may be needing to get the voltage down into reasonable ranges before "it goes back in the box."
I note on the 500P schematic that the  mic channel preamp tubes are not decoupled from the 6L6 screens - same node which is downstream of a choke and one 5K resistor.
Also, you said you were doubting your meter - have a way to check that out?

[rafe]

I am going to hook it up to my single ended Gibson ga-5 . The meter is just a probe I made out of a 6l6 base years ago, it is hard wired to a Simson milliamp meter. it's probably prudent to check the values on all the 65 year old components; resistors and those black molded pyramids. I did not recheck the voltages with the tubes back in ......I'll do that after checking the R's and C's

[bmccowan]

I hope you have a multi-meter under your tree.

[rafe]

I have a few decent multi-meters, I asked Santa for a fluke, I don't think he ever got my change of address though.....I am going to check the bias on the power tubes  with my meter and ohms law ........I'm thinking (and I could be off base) that the meter probe I used is fluctuating because the cathodes are tied together and it's seeing the push pull?? Not that it matters at this point....I'm going to check things out later

[rafe]

biased at 37.45 which i'm happy with ......the resistors are fine  there is an odd one that is kind of buried it's a dog bone bl r r r silv and it reads 22ohms I think i'll put a 2.2K there, I resoldered any suspect eyelets and pins and i'm going to go and play it with the replacement 6l6's and if it passes the taste test ,it going to remarry it's 15" alnico .....and see how it does