Lafayette LR-4000 Schematic or service manual

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Techfixer

New member
Joined
Nov 5, 2016
Messages
6
Location
Boston MA USA
Hi All,
I've just bought a Lafayette LR-4000 with a bad channel and I need schematic or service manual to repair it.
I've checked the usual places like HiFi engine but it seems to be Unobtainium. Would anyone here have a copy.
I need only the amplifier section.

Thanks,

Techfixer
 
Hi Techfixer, I also have a Lafayette LR4000. I picked it up from ebay around 2006. I lucked out. The ad said it was used in the guys garage for years, bought it off his brother, and now had scratchy controls with dead spots in the volume, and a power cord shortened to about 6 inches to fit on a shelf with a plug right behind it. I won it cheap. There was a thick layer of "felt" like dust that smelled of stale cigarettes. After a couple of cleanings and replaced the cord, I had a nice working unit for years. the AM and FM section was a little jacked with the alignment being off, but not too bad. It did sound great playing records, quad, stereo, and mono on the various setting options. About 4-5 years ago, I started getting intermittent "pops" or "crackles" in one of the channels and the sound wasn't as good as it used to be. I found a place not too far that worked on vintage tube radios, and solid state gear. I took my stereo in for a "check up, alignment, and find out what else might be needed". Unfortunately, they did a poor alignment, and replaced the 2 main filter caps, that's it. It still had some issues I described, and the AM alignment was for crap. About 2 years ago, There was a small pop, and I lost one of the rear channels. No fuses were blown. I replaced the unit with a Yamaha natural sound of the same era. It sounds good with most records and FM listening, but nothing as good as my LR4000, which I still have on a shelf. For about 10-12 years I have learned to work on old tube radios, but am a bit intimmidated with the solid state stuff of the 70's. However, after researching over the past year, I think I will attempt a recap, and repair of my Lafayette. Sorry for the long post. I've been a "lurcker" on the forum since aorund 2008. This might be my first post? I am interested in how your repair turns out, and if you have any tips.
-Dennis
 
Yeah I was going to go that route but it's just the owners manual with a schematic. I went with a SAMS Photofacts instead. I'll let the forum know how that all works out.

Techfixer
Hi All,
I've just bought a Lafayette LR-4000 with a bad channel and I need schematic or service manual to repair it.
I've checked the usual places like HiFi engine but it seems to be Unobtainium. Would anyone here have a copy.
I need only the amplifier section.

Thanks,

Techfixer
I have one!
 
Hi Techfixer, I also have a Lafayette LR4000. I picked it up from ebay around 2006. I lucked out. The ad said it was used in the guys garage for years, bought it off his brother, and now had scratchy controls with dead spots in the volume, and a power cord shortened to about 6 inches to fit on a shelf with a plug right behind it. I won it cheap. There was a thick layer of "felt" like dust that smelled of stale cigarettes. After a couple of cleanings and replaced the cord, I had a nice working unit for years. the AM and FM section was a little jacked with the alignment being off, but not too bad. It did sound great playing records, quad, stereo, and mono on the various setting options. About 4-5 years ago, I started getting intermittent "pops" or "crackles" in one of the channels and the sound wasn't as good as it used to be. I found a place not too far that worked on vintage tube radios, and solid state gear. I took my stereo in for a "check up, alignment, and find out what else might be needed". Unfortunately, they did a poor alignment, and replaced the 2 main filter caps, that's it. It still had some issues I described, and the AM alignment was for crap. About 2 years ago, There was a small pop, and I lost one of the rear channels. No fuses were blown. I replaced the unit with a Yamaha natural sound of the same era. It sounds good with most records and FM listening, but nothing as good as my LR4000, which I still have on a shelf. For about 10-12 years I have learned to work on old tube radios, but am a bit intimmidated with the solid state stuff of the 70's. However, after researching over the past year, I think I will attempt a recap, and repair of my Lafayette. Sorry for the long post. I've been a "lurcker" on the forum since aorund 2008. This might be my first post? I am interested in how your repair turns out, and if you have any tips.
-Dennis
Hi Dennis,
I was able to repair it with the Sams photofacts however all the Sams included was a parts layout and a schematic without any voltages or alignment specs. One of the output transistors and a driver were shorted and that's why that channel was out. I tried just using some generic NPN output but that did not go well.
The unit wants "matched output transistors" (same beta gain) so I had to go on eBay and find the exact Toshiba transistor. Lucky for me the gain was in the right ball park. As for alignment I was able to check the other channels and match the voltage and quiescent current draw. I don't remember what it was ...something like 12ma (you remove the fuse for that channel and put a current meter on the 2 fuse holder terminals and bring it up slow on a variac watching the varian's current draw. At idle with no signal it should draw less than an amp. Good luck!

Techfixer
 
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