Up for sale here is this scope power supply board rebuild set for the Marantz 4400. This includes replacements for all 8 transistors on the P900 scope power supply board.  If your scope is having issues, I would recommend rebuilding the power supply board first, but if that doesn't solve it then it might be a bad scope board transistor.  Before you do anything, it is a good idea to clean the connector pins on the scope board with a pencil eraser, since they tarnish and that can prevent your scope tube from working properly.

This kit includes four MJE15032G transistors (to replace the heat-sinked 2SC1507 transistors at H905-H908), four 2SK30Y FETs (to replace the four 2SK30Y FETs at H901-H904), and a piece of heat-shrink tubing for the FETs.

I will include surprisingly well-written instructions, but this is a moderately complicated rebuild, and you should know what you're doing and have a decent soldering iron and a little heat-sink compound. This kit may not fix your Marantz if it has other issues, but it will definitely help it run better. Please see my pictures for details.

US shipping and handling is $5, and international is $18, no matter what quantity you buy. All my small parts are set up for combined shipping, so just use the "add to cart" feature and then check out all at once, and it will combine shipping. If you have any questions, please ask.

Looking for more parts? I have power switches, feet, pushbuttons, top case screws, bottom screws, faceplate screws, white LED fuse lamps, blue LED fuse lamps, 6.3v bi-pin bulbs, 8v bi-pin bulbs, 12v bi-pin bulbs, wired 8v 60ma bulbs, new power cords, new main capacitors for the Marantz 1060/2230, wired Pioneer speaker plug replacements, new 630v yellow film capacitors at 30 different values, a large variety of transistors for vintage stereo repair, new 250v yellow film crossover capacitors, and more. Just use "add to cart" on everything you want and then check out for combined shipping.