See if this assembly manual matches better:
Scott LK-48B
- Thread starter knockbill
- Start date
knockbill
Lunatic Member
Thanks,,
Yep it does match better but not exact,,, The first one I got is way off, as it only has 2 pots located between output tubes,, mine has the 4 bias/balance pots in the center of the chassis, as does the one you just posted... I have it downloaded...
But this manual and schem would be nice to get printed,,
Also there seems to be "Double Check charts", AF1, AR1 and AM1 that came with the original kit"
I cant find them online,, but they would be good to have also, as checking out a kit build that wasn't assembled properly in the first place, and had someone in here a while ago that apparently gave up!!!
I haven't removed a component yet that was soldered right,,, soon as I removed one end the part would fall out, really bad solder work!!!!
Yep it does match better but not exact,,, The first one I got is way off, as it only has 2 pots located between output tubes,, mine has the 4 bias/balance pots in the center of the chassis, as does the one you just posted... I have it downloaded...
But this manual and schem would be nice to get printed,,
Also there seems to be "Double Check charts", AF1, AR1 and AM1 that came with the original kit"
I cant find them online,, but they would be good to have also, as checking out a kit build that wasn't assembled properly in the first place, and had someone in here a while ago that apparently gave up!!!
I haven't removed a component yet that was soldered right,,, soon as I removed one end the part would fall out, really bad solder work!!!!
Here’s the matching schematic:
kvflyer
Super Member
I have worked on a lot of Scott amplifiers and it was not unusual for them to parallel the sections of the filter capacitors. It is usually shown in the appropriate schematic. Mind you, there were a lot of changes within the models. The 299C had at least 7 different "versions". Some changes were very subtle; others were very different. It's good to see you cleaning up that LK-48B. I have to say that in the condition that you received it, it had "repairs" that did not look very professional.
knockbill
Lunatic Member
Hi
Thanks for replying,,, Yep it was in very rough shape,,, I'm trying to clean it up as I go the best I can, but its still ugly!! Wish chassis lettering was still on it,,, I had to find a map to see where all the tubes go!! The outputs/rectifier are in line,, but wasn't sure about the preamp tubes!
I think we found a manual and schem that will more closely match this guy,,, gonna see if my son can make a copy for me at work,,,
I'm going to try to get one channel wired right and see if it will fire up, as there is only one original OPT,, and the odd one isn't wired like the original, so we'll see how that goes, I may have to disconnect it from the rest of teh ckt...
Still baffled by the speaker wiring to the switch and terminal strips,,, I got the PS and bias/filament supply sorted... Started on the (Left in pic) side OPT ckt,, and all the solder joints will need to be cleaned and re soldered.. but it looks a little better than it did... I think its going to be an adventure, but I always wanted a Scott!!!
Thanks for replying,,, Yep it was in very rough shape,,, I'm trying to clean it up as I go the best I can, but its still ugly!! Wish chassis lettering was still on it,,, I had to find a map to see where all the tubes go!! The outputs/rectifier are in line,, but wasn't sure about the preamp tubes!
I think we found a manual and schem that will more closely match this guy,,, gonna see if my son can make a copy for me at work,,,
I'm going to try to get one channel wired right and see if it will fire up, as there is only one original OPT,, and the odd one isn't wired like the original, so we'll see how that goes, I may have to disconnect it from the rest of teh ckt...
Still baffled by the speaker wiring to the switch and terminal strips,,, I got the PS and bias/filament supply sorted... Started on the (Left in pic) side OPT ckt,, and all the solder joints will need to be cleaned and re soldered.. but it looks a little better than it did... I think its going to be an adventure, but I always wanted a Scott!!!
Attachments
knockbill
Lunatic Member
Found what I think is the proper assembly manual, dated 1963,, and have been following it as well as possible to get the speaker ckts wired correctly,,
View attachment 3775937View attachment 3775938View attachment 3775940
View attachment 3775937View attachment 3775938View attachment 3775940
Last edited:
knockbill
Lunatic Member
Thanks Paul,
Yep,, I have a sack of those little knobs,,, used some on a WA-P2 also,,, I had to borrow the inside Bass/Treble knobs off the SS Scott I cant find a couple small transistors for,, But at least I know what I need for it!!!!
I put some 6U8s in it yesterday and traced teh signal thru them,,, and also tried some 12AX7s
(I thought) but they need the output tubes in, as the DC supply is for the cathodes also,,, But as my eyes are failing me,,, I put a 12AU7 in on one side, along with bad tube and spent an hour trying to find out where I lost the other channel!!!
Gotta find a few AX7s and 6BQ5s to try it out further, at a lower B+ now,,,
Dont get old!!!
I forgot,,, where do you get teh output tubes for this?
Yep,, I have a sack of those little knobs,,, used some on a WA-P2 also,,, I had to borrow the inside Bass/Treble knobs off the SS Scott I cant find a couple small transistors for,, But at least I know what I need for it!!!!
I put some 6U8s in it yesterday and traced teh signal thru them,,, and also tried some 12AX7s
(I thought) but they need the output tubes in, as the DC supply is for the cathodes also,,, But as my eyes are failing me,,, I put a 12AU7 in on one side, along with bad tube and spent an hour trying to find out where I lost the other channel!!!
Gotta find a few AX7s and 6BQ5s to try it out further, at a lower B+ now,,,
Dont get old!!!
I forgot,,, where do you get teh output tubes for this?
Lavane
Lunatic Member
Do you mean the Russian tubes? The Russian 6P14P-EV's are rugedized 5,000 hour long life 7189's really, I bought from this one seller. They were nicely matched and I never got a noisy or dud tube no matter what Russian type tube I bought from him. But he's closed up shop unfortunately.
Maybe someone will chime in with a trusted seller they use?
knockbill
Lunatic Member
Yep,, the guy you told my buddy Mike about,,, I didn't know where you got them,,, but I'm not too far away from needed some output tubes!! I'll try to find some 6BQ5s and make sure I dont run em too hot,,,, I got signal thru teh preamp stages and can pick it up on teh output tube grids,,, so its gettin closer,, VC doesn't work tho,,, I think I may have wired teh new pot wrong as I had the wrong manual when I put teh new pot in,,, But the resistor values around teh VC/loudness ckts dont match the manuals or teh schem completely either!!
This one is a lot of fun for small money!!!!
This one is a lot of fun for small money!!!!
knockbill
Lunatic Member
Here it is running thru preamp, to output tube socket , and new VC/loudness pot with new cap/resistors working,, Balance and Tone stack working... With Steely Dan playing thru Signal Tracer amp!!
Cant wait til next hamfest/radio show to grab some 6BQ5s and dig into output stage!!
Cant wait til next hamfest/radio show to grab some 6BQ5s and dig into output stage!!
Attachments
knockbill
Lunatic Member
Yep,,
uses 7189s,,, but I can run/test it with 6BQ5s,, I have it on variac with a SS rectifier,,, just bring it up to 400VDC and htr voltage,,, Its weened off the DBT and played half dozen CDs thu its preamp thru a the signal tracer amp,,,
Need to test output stage now, and dont have any tubes!!
uses 7189s,,, but I can run/test it with 6BQ5s,, I have it on variac with a SS rectifier,,, just bring it up to 400VDC and htr voltage,,, Its weened off the DBT and played half dozen CDs thu its preamp thru a the signal tracer amp,,,
Need to test output stage now, and dont have any tubes!!
knockbill
Lunatic Member
Yep,,, if the other one works OK, it will be worth finding a match for it,,, as I dont have a core to get rewound,,, if not,,, its already a really nice preamp!!!!
Even tho the Fishers use the same tubes as this one,,, I dont think they would be near as good in this guy!!!
