Marantz 6300 Restoration

[MarantzRefrb]

A new thread to briefly document this 6300 rebuild - this will take a while to complete. I have not ordered any parts yet.

Thanks to this excellent thread: https://audiokarma.org/forums/index.php?threads/marantz-6300-project.591126/ for doing all the hard work and research!

Built August 18, 1975:

Version 1:

Confirmed v1:

Service Manual data

Schematic:

Layout:

Parts list for P800 power supply and chassis:

Parts for v1 chassis:
(10) Omron switches - 653-VX-5-1A3
https://www.mouser.com/ProductDetail/653-VX-5-1A3?R=VX-5-1A3virtualkey65300000virtualkey653-VX-5-1A3

(2) Bourns 1K pots - PDB181-E415K-102B
https://www.mouser.com/ProductDetail/Bourns/PDB181-E415K-102B?qs=Zq5ylnUbLm6Geetxd75ulg==

(1) WIMA 1uF 50V - C003
https://www.mouser.com/ProductDetail/WIMA/MKS2B041001C00JSSD?qs=sGAEpiMZZMukHu%2BjC5l7YRh698uJ5wVBnux2v0A4wRc=

(1) Elna Silmic II 470 uF 63v
https://www.mouser.com/ProductDetail/555-RFS63V471MK8#5

Parts for v1 P800 power supply
(1) Nichicon 470 uF 63V
https://www.mouser.com/ProductDetail/647-UPW1J471MHD3

(1) Nichicon 330 uF 100V
https://www.mouser.com/ProductDetail/647-UPW2A331MHD

(1) Elna Silmic II 220 uF 25V
https://www.mouser.com/ProductDetail/555-RFS25V221MI5#5

(1) Elna Silmic II 100 uF 25V
https://www.mouser.com/ProductDetail/555-RFS25V101MH4#5

(1) Nichicon 0.47 uF 100V
https://www.mouser.com/ProductDetail/647-UFG2AR47MDM

(1) KSC2073TU - Replacing SD331
https://www.mouser.com/ProductDetail/512-KSC2073TU

(1) MCR72-3G - Replacing 2PIM
https://www.mouser.com/ProductDetail/863-MCR72-3G

EDIT: Corrected WIMA cap at C003

 

[peerson]

I hope you like the 6300. I have a 6200, and I like it a lot. Pretty much trouble-free after the rebuild.

 

[MarantzRefrb]

This particular 6300 hasn't worked correctly in over 30 years, hopefully the new switches will fix the problems with this one. I ordered all the parts last night, and just got confirmation they'll all be here on Thursday.

 

[_tk]

What cartridge are you going to use? My 6350 is rather particular about cartridges due to the high mass tonearm/low compliance cartridge that's needed (I think I got that straight).

 

[MarantzRefrb]

Good question, I hadn't thought that far ahead. I see the Ortofon 2M Blue, or the Stanton 681EEE would work. Do you have a recommendation?

 

[_tk]

I was hoping you would. I haven't strayed too far away from the Audio-Technica models (AT95's and 500 series) due to them liking 2.0g tracking force. I recall people saying that the Ortofon 2M Blue would work as well.

I was also curious if a different headshell than the OE one would be a better choice as well.

Here's a test of the 2M Blue vs AT95ML:

part 1: https://www.analogplanet.com/content/ortofon-2m-blue-versus-audio-technica-vm95ml

part 2: https://www.analogplanet.com/conten...l-vs-ortofon-2m-blue-file-identities-revealed

 

[MarantzRefrb]

Were you able to use your stock Marantz headshell with the ATVM95ML?

 

[_tk]

Stock Marantz headshell fits with my AT95E. So I assume it would work with the AT-VM95 series of carts as well?

 

[MarantzRefrb]

I received all of the parts listed above, from Mouser today:

Everything looks great except for the 1uF 100Vdc WIMA I ordered to replace the little blue tantalum cap on the photo-transistor circuit:

The 100Vdc is too big for this application. I hear that it is possible to replace any cap with the exact same capacitance, but different voltage. If that's true, can I get away with using any of the three choices shown below?

 

[Steven Tate]

What is the voltage rating of the tantalum? They make a 1uF 50V WIMA that should easily fit there if the voltage rating is sufficient - and I’ll bet it is.

 

[MarantzRefrb]

The old blue tantalum was 1uF 25V +/- 20%.

I was just looking at the WIMA 1uF/50V:
https://www.mouser.com/ProductDetail/WIMA/MKS2B041001C00JSSD?qs=sGAEpiMZZMukHu%2BjC5l7YRh698uJ5wVBnux2v0A4wRc=

7.2 mm in length, should've ordered that one.

I guess of the three I currently have, the WIMA 1uF 63V would be best?

Thanks.

 

[Steven Tate]

The 63V should work if it will fit.

 

[MarantzRefrb]

I have a lot of room to work with in this instance, luckily:

Thanks!

 

[Steven Tate]

I’m assuming that’s just a regular tantalum cap, and not some kind of photoreactive component?

 

[MarantzRefrb]

According to the schematic, it looks like it's just a plain cap at C003, maybe used for bypass of PH101 in some condition?:

 

[Steven Tate]

That should work then. Since it shows a polarized cap, you could also use an electrolytic 1uF of 25V or more rating if installed with proper polarity. But I would use the WIMA.

 

[MarantzRefrb]

If I were able to edit the original post and add the correct part number I would.

The correct part to order for C003 - WIMA 1uF / 50V:
https://www.mouser.com/ProductDetail/WIMA/MKS2B041001C00JSSD?qs=sGAEpiMZZMukHu%2BjC5l7YRh698uJ5wVBnux2v0A4wRc=

 

[MarantzRefrb]

Got a lot done tonight, almost done with replacing all of the Omron switches.

First switch I did:

Got (8) of the (10) switches replaced, and the 470 uF cap on the chassis:

Begin the power supply re-cap.

Removed the two orange wire-wrapped posts to get access to the rear:

Board ready:

Done:

I want to replace the interconnects, and possibly do some other upgrades, I left the last two Omron switches until I've decided how to proceed:

Old parts:

Done for the moment, I'll order more parts and pick it back up later.

I still need to figure out how to get to the 1K pots, for pitch, it looks like I have to remove the arm, to get the plate over the pots off.

 

[MarantzRefrb]

I could only find 3 of the stock feet for this TT, and they would fall off everywhere this would go. I decided to convert this 6300 to be able to use the Isonoe feet, for the Technics 1200. This would make the feet more permanent when mobile, and these are height adjustable as well.

Height is nearly perfect:

Used M6 tee-nuts for mounting to the plinth:

Drilled the size up with 5 bits to get the existing hole the same size as the M6:

Ready to hammer:

I was worried about hammering these in, but everything seems to be fine:

Checking the fit of the wood-tapped feet against the belly pan:

Need to drill and tap the metal brace to M6 to finish this up:

 

[MarantzRefrb]

Last foot installed, drilled the metal brace with a 7/32" drill bit, then ran a M6x1.0 tap through it:

Foot installed in bracket, screwed all the way in, mirror showing the clearance between the foot mounting screw, and the components underneath - plenty of room:

All 4 mounted:

Assembled:

I'll probably test the operation of this tomorrow, before taking off the tonearm, top metal cover, and replacing the 1K pitch pots, and last two switches. I love these new feet so far.