Starting Marantz 2325 rebuild

[Steven Tate]

I remember when a fine tooth comb would stick in my hair. Barely remember that is!

Lol. I'm in the same boat. BTW, I got one of those Plato 175 safety shears you told me about. Excellent wire cutters and they do indeed hold onto the cutoff end of the wire so it doesn't fall into the guts of the machine. Very well spent ten bucks. Thanks for pointing me in that direction.

 

[Richs_Trains]

Quick question, I have 170 shears and they don't hold the cut off (which would be rear nice), unless I am using them wrong, what's the difference between the 170 and 175 shears besides cutting thickness? Thanks Rich

 

[rBuckner]

There is an extra little sprung arm besides the two cutting arms. It contacts the lead, if it's long enough, and holds it. I imagine you have to hold the utters closed for it to stay but I'm not sure as I don't use them, my friend does.

 

[Steven Tate]

Just out of curiosity, I tried cutting off about 1mm of wire to see if it would hold it and it did. Now, whether it will do that over time, I can't tell you. But so far, it has held on to everything I have cut.

 

[Richs_Trains]

Well the tails drive me nuts trying to hold on to them and when one falls, oh man, just not a good feeling. Gonna give these a try. Rich

 

[Steven Tate]

After letting the 2325 bench cure for a couple of weeks, I put it back on the workbench to sort out the phono issue (less volume than other inputs). With it on the bench and nothing plugged into the inputs, and with the bottom off, there is a loud hum in phono mode only. If I put my hand near the phono board, the hum gets much louder. If I put the bottom on the case, the hum virtually goes away, but with volume at 50%, there is another noise between a hiss and an ocean sound - but no hum. Could it be a grounding issue somewhere? But it's only in phono mode. Other modes are very quiet even at high volumes. I only replaced the SC458 transistors on the board. Should I change the other ones? Not sure where to start with this. I did recheck the back of the board as Randy suggested and all solder joints look good. But something is amiss with all of this noise in the system and it's coming from that P400 board or something attached to it.

 

[Steven Tate]

Out of desperation, I did a couple of things. I replaced all four 2SC1344's with KSC1845's. not much change in the hum, but less background noise when I put the bottom on and the hum went away. Then I spent thirty minutes checking the bottom of the board again and reflowing some spots. The three points where the shielded signal leads enter the board were a little rough looking, even though I hadn't touched them. After all of that, the hum is only slightly better with bottom off, but virtually non-existent when the bottom panel is attached. Is this normal? And since the background hiss is mostly gone, I think it is usable, although I haven't hooked up a turntable yet to check the volume.

Now... I have another problem post-recap. When I first turn the unit on after it has been sitting, with volume at zero there is a lot of static in one channel for about thirty seconds, diminishing during that time until it is gone. The fact that it doesn't seem to ever come back during use is going to make it hard to track down. I'm going to start with another Deoxit cleaning, and after my experience on the 2275, I'm going to give special attention to pre out/main in jacks. Those internal switches caused a lot of jumping around when setting idle current. After cleaning it was very stable. Any other ideas, or thoughts about my phono hum with the bottom off?

 

[runningdog]

the hum is only slightly better with bottom off, but virtually non-existent when the bottom panel is attached. Is this normal?

I've fought more than one hum on a 2325 before remembering (or being reminded here on AK) to put the bottom cover on. It makes me want to do a complete disassembly of a 2325 someday. So when the chassis goes back together the pieces ground to each other so well there is no difference with the bottom cover on or off...hum free.

 

[Briant8]

Out of desperation, I did a couple of things. I replaced all four 2SC1344's with KSC1845's. not much change in the hum, but less background noise when I put the bottom on and the hum went away. Then I spent thirty minutes checking the bottom of the board again and reflowing some spots. The three points where the shielded signal leads enter the board were a little rough looking, even though I hadn't touched them. After all of that, the hum is only slightly better with bottom off, but virtually non-existent when the bottom panel is attached. Is this normal? And since the background hiss is mostly gone, I think it is usable, although I haven't hooked up a turntable yet to check the volume.

Now... I have another problem post-recap. When I first turn the unit on after it has been sitting, with volume at zero there is a lot of static in one channel for about thirty seconds, diminishing during that time until it is gone. The fact that it doesn't seem to ever come back during use is going to make it hard to track down. I'm going to start with another Deoxit cleaning, and after my experience on the 2275, I'm going to give special attention to pre out/main in jacks. Those internal switches caused a lot of jumping around when setting idle current. After cleaning it was very stable. Any other ideas, or thoughts about my phono hum with the bottom off?

Same thing with mine! Terrible hum that goes away when the bottom is replaced. I did the same thing you did and spent a lot of time trouble shooting, when all it took was the bottom panel replaced....

 

[wurlyman]

P600 Dolby Circuit Board

This one is a veritable pleasure to work on because the whole board comes out and you can work on it on the bench. Lots of 10uF caps on this one just like the tuners. Here is the board after replacing all electrolytic caps - nothing else - and the parts list. Had a shipping issue with the parts I'm waiting on. It's been five days since I ordered from Mouser, and they usually get here in two days. The Mouser warehouse is about 10 miles from here. After five days, no parts, so I checked the USPS tracking. The parts went from Mansfield (10 miles from me) to Ft. Worth (about the same) and then to Amarillo (300 miles away!) then finally back to Ft. Worth where they are now. I will probably get them tomorrow. The system obviously hiccuped on my parts.

P600 Dolby Circuit Board

C601/602 3.3µF/25V - WIMA MKS2 3.3µF/50V Mouser 505-MKS23.3/50/10
C607/608/609 10µF/16V - Nichicon KL 10µF/16V Mouser 647 UKL1C100KDD1TD
610/611/612
613/614/623
624/631/632
635/636
C627/628 47µF/10V - Nichicon FG 47µF/25V Mouser 647-UFG1E470MEM
C641 220µF/25V - Nichicon KL 220µF/35V Mouser 647-UKL1V221KPD

How are you getting the entire board out of the receiver? Are you unwinding wire wraps or un-soldering the posts? Don't know if I'd dare to do that.

 

[MBuras]

The Dolby board in the 2325 has plug in connectors that slide onto pins. Just need to keep the colors/numbers straight but no need for desoldering or unwrapping anything.

 

[Wallie]

Hello Guys!
I've made an online BOM of all components mentioned in this thread (as I understand, this list is largely inspired by Leestero's thread on the 2325 restoration), with links to the specific Mouser product pages. I hope it's okay I share this link here. I have not modified any part, some items are currently out of stock, but you should be able to find suitable replacements.
I make this list for myself as I'm planning on doing this restoration as soon as I get all the parts, and I thought it would be nice to share it with others stumbling on this excellent thread. Thanks Steven Tate, and Leestereo!

So here's the link: https://docs.google.com/spreadsheets/d/1JaAcbN-dXUsYx6ALQSoBtqMAwV9E9TQXRI0nVWu_42I/edit?usp=sharing

I'm new to the forums, so if sharing this might be a problem, please remove this post! If anyone wants to edit the list, shoot me a pm or something, and I can send you an editable version or something?

 

[Bert 1100]

I've made an online BOM of all components mentioned in this thread

Hey Wallie, thank you for putting this together, I have a 2325 coming in very soon for a full resto....

 

[Steven Tate]

Love the spreadsheet. That will be very helpful to others. I've been listening to this 2325 for 6 months now without a hiccup. I'm running it through some JBL L-100's that I built new crossovers for based on another thread. Since my primary genre is classic rock, all I can say is that this combination of 2325 and modified L-100's just kicks ass.

 

[SaturationPt]

I absolutely love it when someone does this, ... saves so much time measuring lead spacing and looking up substitutes. Thanks Wallie!

 

[Wallie]

Hey guys, thanks for the kind words! It's nice to know that people are using this I have this thread and my BOM open every night when I'm retreating to my cozy place and just work on my 2325.

 

[MouseMaster]

Out of desperation, I did a couple of things. I replaced all four 2SC1344's with KSC1845's. not much change in the hum, but less background noise when I put the bottom on and the hum went away. Then I spent thirty minutes checking the bottom of the board again and reflowing some spots. The three points where the shielded signal leads enter the board were a little rough looking, even though I hadn't touched them. After all of that, the hum is only slightly better with bottom off, but virtually non-existent when the bottom panel is attached. Is this normal? And since the background hiss is mostly gone, I think it is usable, although I haven't hooked up a turntable yet to check the volume.

Now... I have another problem post-recap. When I first turn the unit on after it has been sitting, with volume at zero there is a lot of static in one channel for about thirty seconds, diminishing during that time until it is gone. The fact that it doesn't seem to ever come back during use is going to make it hard to track down. I'm going to start with another Deoxit cleaning, and after my experience on the 2275, I'm going to give special attention to pre out/main in jacks. Those internal switches caused a lot of jumping around when setting idle current. After cleaning it was very stable. Any other ideas, or thoughts about my phono hum with the bottom off?

Steven, whatever happened with that rushing sound on power up? My 2325 was exhibiting that behavior when I took it out of service 10 years ago. I will be rebuilding it soon, and I am very interested in hearing what you found.

 

[Steven Tate]

Steven, whatever happened with that rushing sound on power up? My 2325 was exhibiting that behavior when I took it out of service 10 years ago. I will be rebuilding it soon, and I am very interested in hearing what you found.

When I did a good Deoxit cleaning of the internal pre/main contacts, it went away. I inserted an RCA cable into each jack many times while giving it quick shots of Deoxit. I've been listening to that 2325 for six months now and it is darn near perfect.

 

[MouseMaster]

When I did a good Deoxit cleaning of the internal pre/main contacts, it went away. I inserted an RCA cable into each jack many times while giving it quick shots of Deoxit. I've been listening to that 2325 for six months now and it is darn near perfect.

Good to know it was a simple fix. Thanks! I am the original owner of this 2325. I have not seen the actual unit in 10 years. It is in the other room still sealed in its original box and packing. I packed it up in early January 2007. I've had it since September 1977. Probably has several thousand hours on it.

 

[Steven Tate]

Wow. That would be an interesting unit to see. When I started out, I intended to recap the power supply, power amps and filter caps. One thing led to another and I ended up refurbishing the whole thing. I replaced all caps as well as some recommended transistors and diodes. Like I said, it drives some modded JBL L-100's and definitely rocks. Look forward to seeing what you do to yours when you open it up.