Members Bim1959 Posted February 5, 2012 Members Share Posted February 5, 2012 Anyone know where I can get a CLEAR schematic or a PCB layout of this amp? I just bought one intending to repair it and it has 2 resistors burned beyond recognition, and the print I got from the Legend amp page is so bad it isnt funny. It's the 2 resistors coming off the power supply diodes - one goes to a tube, the other goes to a power supply capacitor. I've read all sorts of good things about these amps and I really want to bring this one back to life. Link to comment Share on other sites More sharing options...
Members teemuk Posted February 5, 2012 Members Share Posted February 5, 2012 Originally Posted by Bim1959 ... the print I got from the Legend amp page is so bad it isnt funny. The schematics on that site are very poor quality. A little bit of more persistent searching and you should be able to find the PC5003 board schematic in much, much higher resolution and as a better scan.I know, I found one too.Unfortunately, I have about 20 CDs full of schematics so it's kinda "lost in the archives" and I'm not going to spend an hour + of digging up something that you can find as well....Anyway, there should be a 100uF filter cap directly after the HT rectifier diodes. In parallel of it there should be a 300k bleeder resistor. This first filter stage, according to schematics, only feeds a second filtering stage, which isolated from the first with a 10k resistor. No connection to any of the tubes, only to a second filtering stage. This second section will again have a 100uF cap and a parallel 300k bleeder resistor to ground. The node will also feed one tube section constructing a long-tailed pair with feedback loop (it mimics the power amp clipping and also introduces a presence control). The node also again feeds a third filtering stage, again isolated with a 10k resistor. This stage only has a 50uF filter cap (22uF in some circuit revisions) and doesn't have a bleeder resistor at all. This stage powers the tube section preceding the tonestack (one common cathode amp directly coupled to emitter follower). The final filtering stage is once again isolated with a 10k resistor. Filter cap is either 50uF or 22 uF, depending on circuit revision. This powers the first preamp tube and the two common cathode stages utilizing it.Which brings us to an interesting point: There are at least two revisions of the PC5003 board, which have slight differences such as the aforementioned filter cap values and some stuff related to the channel control arrangement (particularly that of "Rhythm Drive") and the input stage. So, you may essentially be looking for more than one good schematic, you'll be needing at least two, possibly three if your amp revision differers from them too much.Anyway, you should be able to find at least two decent schematics from the Internet. Just forget the crappy Legend amp tribute site. Link to comment Share on other sites More sharing options...
Members chriscnb Posted February 5, 2012 Members Share Posted February 5, 2012 I can't help you, but good luck, these are awesome amps. I used to have one...they're the ones with a wicker front right? Let us know if you end up restoring it Link to comment Share on other sites More sharing options...
Members diddlybo Posted February 5, 2012 Members Share Posted February 5, 2012 I bought one new back in the early 80's. It wasn't the best amp I ever owned but it was certainly the loudest. It was the amp Billy Gibbons used to record Eliminator. Link to comment Share on other sites More sharing options...
Members Bbreaker Posted February 5, 2012 Members Share Posted February 5, 2012 I had a Legend half stack up until 3 years ago when I traded it for a USA Fender Fat Strat.The Legend was completely stock with the brown grill.I found the 4x12 about 10 years after I bought the head.You can find these for a song.The head cost me $100.00w/footswitch and the 4x12 was $250.00.****I agree. Not the best but one of the loudest amps around.**** Link to comment Share on other sites More sharing options...
Members Bim1959 Posted February 9, 2012 Author Members Share Posted February 9, 2012 Yep. Mine has the wicker front. Looks gorgeous. I did some looking online and found MusicParts.com who had a set of schematics for my Legend. However, PC5003, the preamp board, is still very fuzzy as far as trying to read component numbers and values. With a little luck I'll have pics to post soon. Link to comment Share on other sites More sharing options...
Members Reauchambeau Posted February 10, 2012 Members Share Posted February 10, 2012 I've got a broken one at home too. Link to comment Share on other sites More sharing options...
Members Bim1959 Posted November 10, 2012 Author Members Share Posted November 10, 2012 So nobody can help me out with it? I still have not found the right schematic for this amp. It must be a different revision as mine still runs from the HV diodes directly into these I'm guessing 5 or 10 watt resistors which stand above the PCB. If someone wants to give me pics of their PCBs (or maybe I'll have to post one of mine) maybe that'll be all I need to make it work. Link to comment Share on other sites More sharing options...
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