Marantz 6300 Project
- Thread starter Echoplex
- Start date
BrandonS2185
New Member
Thank you! I'm sure I'll have more questions.
IGSTER
Active Member
Marantz 6300 Project: Part 1
After spending two weeks on researching and locating replacement parts, I finally got started on my 6300 project.
First, I went through and replaced all ten of the micro-switches with new equivalents from Omron. The old ones were fairly worn out and a few barely had any spring actuation left in them. As you can see, the new ones have a slightly longer lead and the common contact is located on the bottom side instead of being off to one side.
Original switch: Omron LV-3H-1A-S (3A125.250VAC)
Replacement switch: Omron VX-5-1A3 (5A125.250VAC)
Next, I replaced the SCR (thyristor). I've been having trouble with my photo unit circuit due to the Automatic Shut-Off not triggering properly, so I went ahead and found this equivalent from ON semiconductor.
Long story short; the collector on the phototransistor is coupled to the gate of the SCR, so as the collector voltage rises the gate voltage on the SCR also rises, thereby triggering the circuit to turn on.
Original SCR (thyristor): NEC 2P1M
Replacement SCR: ON Semi MCR72-3G
Is it ok to cut the ends of the thyristor shorter so it doesn't sit so high in the board or should I leave the legs long and solder it the way it is? Will cutting the legs shorter affect the switch?Marantz 6300 Project: Part 1
After spending two weeks on researching and locating replacement parts, I finally got started on my 6300 project.
First, I went through and replaced all ten of the micro-switches with new equivalents from Omron. The old ones were fairly worn out and a few barely had any spring actuation left in them. As you can see, the new ones have a slightly longer lead and the common contact is located on the bottom side instead of being off to one side.
Original switch: Omron LV-3H-1A-S (3A125.250VAC)
Replacement switch: Omron VX-5-1A3 (5A125.250VAC)
Next, I replaced the SCR (thyristor). I've been having trouble with my photo unit circuit due to the Automatic Shut-Off not triggering properly, so I went ahead and found this equivalent from ON semiconductor.
Long story short; the collector on the phototransistor is coupled to the gate of the SCR, so as the collector voltage rises the gate voltage on the SCR also rises, thereby triggering the circuit to turn on.
Original SCR (thyristor): NEC 2P1M
Replacement SCR: ON Semi MCR72-3G
Echoplex
Active Member
Thanks for the kind words!
Echoplex
Active Member
Yes, but before you do, I would use the old/original component for visual reference to see how long the leads were, then solder the new one into place and you should be good to go!
No, but you do want to take care not to trim the leads to close to the terminal board. Ideally, you want them to extend out past the board a little bit to ensure a good solder joint.
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IGSTER
Active Member
Thanks for this awesome Marantz 6300 Project. This will be a great help for many 6300 owners for years to come.
SuperDodge
New Member
This is a round LED, right?. Is there a rectangular one available from Mouser that would work?
Echoplex
Active Member
Yes, but they don't have the domed shape end on one side like the originals did, so I went with LN28RPX since it fit the eyelet hole.
bryans12v
Marantz / Altec Junkie
Anyone have a source for these red LEDs? Working on a 6300 now that has the infamous issue with not shutting down. Im ordering a new optic sensor as well but seems Mouser has the LED listed as obsolete.
Ive tried searching through mouser for a replacement but only came up with the Dialight 560-0104F which has no datasheet. Figured Id ask before taking the chance. Id prefer to stick with mouser if possible as I have a cart saved for some other projects.
Ive tried searching through mouser for a replacement but only came up with the Dialight 560-0104F which has no datasheet. Figured Id ask before taking the chance. Id prefer to stick with mouser if possible as I have a cart saved for some other projects.
gregmcm
Active Member
I took an ordingary red LED and bent it to point at the sensor - worked just fine.
slickshaft
New Member
I just picked a Marantz 6300 out of the trash. Can you believe it? LOL. Anyways, I'm going to be doing a recap on it and this thread is going to be very beneficial. I'll be reading through it thoroughly.
bryans12v
Marantz / Altec Junkie
That's actually the one I used!
Quick question though. I've got almost everything sorted out with this table except for this one issue with the up and down cuing. Down always seems to work however sometimes the up cue will not.
I noticed that when the up cue doesn't work, the down button will cue it up. It's almost like to down button is cuing both up and down. The cue up button will sometimes work fine but when it wont work, the down is working both functions. Isnt that strange?
I think I'm going to shotgun all the micro switches but wondering it it may be a linkage issue.
Echoplex
Active Member
Good, glad you found the right one.
Yeah, those micro switches.....man, they're pesky bastids. I would definitely replace them all.
Also, you can't overlook the mechanical aspect of the switch buttons either. All of them have these spring-loaded levers that are made out of paper-thin metal. After repeated use, they get bent out of shape and cause the switch to act finicky because the lever can't travel far enough to hold the button down and actuate the switch. I chased my tail on that problem, but finally got it figured out.
In your case though, it sounds like you might have a wire crossed up somewhere. Grab your multi-meter, set it to continuity, and retrace every wire and check switches in open and closed positions.
Somewhere, you've either got something crossed or one of your switches is failing to get enough voltage to trigger the auto cue, and could also be a bad component.
Try checking those first, and let me know.
Best!
Yeah, those micro switches.....man, they're pesky bastids. I would definitely replace them all.
Also, you can't overlook the mechanical aspect of the switch buttons either. All of them have these spring-loaded levers that are made out of paper-thin metal. After repeated use, they get bent out of shape and cause the switch to act finicky because the lever can't travel far enough to hold the button down and actuate the switch. I chased my tail on that problem, but finally got it figured out.
In your case though, it sounds like you might have a wire crossed up somewhere. Grab your multi-meter, set it to continuity, and retrace every wire and check switches in open and closed positions.
Somewhere, you've either got something crossed or one of your switches is failing to get enough voltage to trigger the auto cue, and could also be a bad component.
Try checking those first, and let me know.
Best!
Thank you so much for this entire rebuild info. I am in the midst of doing the same although not as in depth. I started the recap only to find I have the later 6300 version so I still need to replace C808 which is a tantulam cap and C801 a ceramic cap. Not sure on the tantalum, looks Luke a radial dipped based on pics, which Florida has but not mouser where I have ordered most. Can you help on which one I need as well as the thyrystor which you referenced as ON semi MCR 72-36, which I have not been able to find. Thanks
