SWR 350 bass chrome

[DWBUZZ]

Hi, I'm looking for a layout drawing for SWR 350 bass mfg. date 7-01 preamp and power amp. Also parts list for preamp. I got the schematics from Fender but was told they didn't have layout drawings. Preamp pcb says silverado. Thank you.

[Enzo]

I was an authorized SWR service center before they were swallowed up by Fender, and as an authorized Fender warranty station, I continue. But I have never seen layouts for SWR. As far as I know they never issued any. It is not that large a circuit, we ought to be able to identify parts from the schematics.

There are parts lists, but not for the boards. The list is for stuff like handles and corners and feet, fuse holder, power switch, stuff like that. As parts are all on the schematic, if we need a list, we can make one from that drawing.

[DWBUZZ]

Thanks, I,m not very experienced in amp repair but am trying to learn by doing so a layout drawing makes it easier. Looking at the schematic for the preamp Q1 doesn't give any values or numbers, do you know what transistor it is, the values or part number is? I wish I still lived in Michigan then I'd bring it to you. I was trying to locate the source of some noise by poking around with the eraser end of a pencil when I touched the bridge rectifier center bolt and one of the 116v terminals (NOT RECOMMENDED) and now it makes bad noise when the master volume is moved from o . Any ideas on what I messed up?

[Enzo]

No idea other than maybe you burnt a ground trace open on the board.

Q1 is just a generic N-channel JFET, probably not critical, something like a J111 would probably work. Look on the face of the part, what is printed there? You may have to angle the light just right.

[DWBUZZ]

Thanks again for sharing your vast knowledge and experience. I tried to look on the piece face but couldn't read the top row of numbers only the bottom which was 5457.

[J M Fahey]

http://www.onsemi.com/pub/Collateral/2N5457-D.PDF

[DWBUZZ]

Hey, Just thought I'd follow-up in case anyone is interested. The gain pot was broken off the pc board that was causing the noise that I was poking around trying to find. I was too impatient to wait and order a new one so I soldered some wire on the terminals and soldered it back in the board. amp worked fine but the fan wouldn't come on. Found I had burned the ground wire off the board, reattached and now it goods pretty good, although not as good as my old old ampeg V-4B.