I need JBL Schematics

[ben62670]

Hey guys I am usually in solid state, but my buddy blew a BP-1200, and we have to fix it. Does anyone know where to get the schematics.

Thanks
Ben

[Perry Babin]

Email me.

babin_perry@yahoo.com

[coderjedi]

Originally posted by Perry Babin
Email me.

babin_perry@yahoo.com

Wow!! Perry Babin!? I am SO very pleased to actually "meet" you! I've been utilizing your site for years to brush up on certain areas and to learn many many things. I am slightly in awe to see that you not only created such a great site that contributes so much information freely, but also actively participate on forums further contributing to the masses. I salute you sir.

Anyhow, I am ben62670's buddy with the blown JBL BP1200.1. Long story short, I bought a JBL GTO 1201.1 II refurbished for $275 because I couldn't afford retail, but it blew, and I didn't feel I was well enough experienced to fix it, so I bought another amp, a JBL BP1200.1 and now it did the same exact thing! Both blew all of the N-channel MOSFETs! Why!? I think JBL has some issue with this! Both amps were working great, and suddenly fried for no apparent reason what so ever! I don't get it, but, I really can't afford another amplifier now, and so I am left with the only option of trying my best to repair it.

I would be so very greatful if you could email me any information you may have so I may identify the badly damaged and undistinguishable parts, most importantly the values of the resitors next to the MOSFETs.

I will email you so you have my address. Thank you so much, and again it was great "meeting" you!

[Perry Babin]

You can get all of the values from the schematics. If there are areas where you cannot read the circuit board designations, describe the general area of the damage and I'll post a few of the photos I have.

[ben62670]

Thanks Perry. I told my buddy you guys are awesome over here!

[ben62670]

Hey guys now we are up to 3 dead JBL's. This one is a GTO-1004. It goes right into protection mode. We are hoping this can be a simple fix. We need a schematic for this one too if possible. Thanks again.
Ben

[Perry Babin]

If the amp goes into protection, the most likely fault is shorted output transistors.

I don't have the manual for that amp.

[ben62670]

The tip35c's have full continuity on the base to emitter. They failed on my Heath kit transistor tester.
CoderJedi is my friend.

[Perry Babin]

It's strange for a TIP35/36 to fail shorted from base to emitter. They typically fail shorted collector to emitter.

Have you pulled it and checked it out of the board?

If it's shorted between any 2 legs out of the board, it's defective.

[ben62670]

Sure did. Mike pulled it, and I tested it out of the amp. Still a dead short between b, and e. Hooked it up to my Heath kit IT-121, and no good. I hope nothing else is fried.