Marantz 2600 Refurb Thread

[rBuckner]

Ah, c.coyle, alas, you are correct! I can say this, there's not much else in Winslow!!

Here is more progress...

I found that the standoffs wouldn't rotate when trying to snug them onto the bottom resistor so had to switch to building it top down.

There we go!

Wires soldered back on and relay socket properly attached now. Before it was flopping around.

I'm not sure I showed the tone control boards back in place or not. The shield was polished and I tie-wrapped some of the wiring up for neatness sake.

The new power relay installed.

Next is the speaker relay board which will get a new relay and one e-cap.

The peak LED board has been taken off again in prep of removing the amp "tunnel".

 

[rBuckner]

Next the rear panel is loosened and hinged down. There were two missing screws. Then the dusty old fan is unfastened and put on top to unsolder the wires.

The foam gasket is rotted and will be replaced with homey store weatherstrip. The fan gets replaced with a new EBM Pabst ball bearing unit (thanks to a tip from Tom / catrafter on my 2500 rebuild). The bearings on this guy were a bit noisy anyway!

The wires that unplug matched the ones from the 2500 sketch I did before so out comes the amp module.

Hey! More dirt!! I did a preliminary Windex clean after this shot was taken.

More dust for me.

The amp driver boards are off. Note that there are 3 blue caps on the top board someone replaced. The soldering was done well though.

The heatsink halves separated. All of the output transistors are Marantz marked originals which is a good sign. The amps were never blown. The bottom half has the output transistor connection board. I've already picked at the old flux on the board.

Here is the unseen outputs.

The caps out of the partially recapped board. Out with the Xicon and in with the Nichicon! Interestingly not all caps were replaced and the two larger ones are pretty swollen. I have some cleaning to do as this unit has that sticky dust that was on everything else. I have matched up two sets of KSC1845's for the diff pairs and installed them. There were some cooked looking resistors that I will be replacing with higher wattage ones just ordered. I just got shipment notification from Mouser so should see them Thursday/Friday. See y'all then!

 

[Bkphoto]

 

[onwardjames]

Holy chit, rBuckner! If you charged what your work is really worth.....this is such a treat to observe.

 

[Denten]

 

[rBuckner]

It's time to start the cleanup. Here are the outputs, drivers and biasing semi's. The pile of old mica insulators will be tossed later in favor of new ones.

The gooky heatsinks.

Here the output transistor connection board has been pulled. The white things in the heatsink are insulator bushings for the screws that held the output transistors in.

The heatsink half has caked on thermal grease. It was fairly dry but not quite dead yet!

The board brackets were washed. Up at the upper left are the insulators. They were later wiped down.

I picked the soldering flux a bit and soaked/scrubbed the connection board that was loose in alcohol and the two driver circuit boards. A final wash with Windex and they are very clean.

The heatsink was cleaned (trust me!) as well as the two thermal switches. They were regreased with thermal compound and reinstalled and the insulators set in place.

 

[rBuckner]

I wiped the individual heatsinks down and soaked them in a can of paint thinner for a couple of hours then scrubbed them. After drying with paper towel, I washed them with Windex and rinsed them off. I noticed they were fairly uneven on the bottom and had some sharp edges where they will contact the main heatsink so I filed them down a bit to make them flatter.

I wiped down the power output transistors and got like 98% of the old thermal compound off. I didn't want to use any solvents even though the case and leads are supposed to be sealed. It wasn't worth finding out!

The drivers and biasing parts are back on the heatsink. What you don't see is that the connection board has been reattached to the back side.

Thermal grease has been thinly applied to the output transistor and the new mica insulator slipped on. Another thin coat then gets applied to the insulator and to the bottom of the individual heatsinks. The transistor is held in place and then placed on the heatsink and wiggled around to locate the base and emitter pins to the holes in the connection board then screwed in place. That reminds me, the outputs' screws were all very nearly loose when I went to remove them. I'm guessing this was due to the connection board drying out and/or compressing over time or perhaps the many heating and cooling cycles over the years.

Several hours later this task is done!

This little guy was found smashed under one of the output transistor heatsinks. It's the size of the washers on the mounting screws. None were missing so it had to be a factory error. Oops!!

None of the soldering was done until all outputs were snugged down and re-snugged. They shouldn't be cranked down, just enough to make sure they won't come loose and maybe just a bit more. Looks like I need to trim some leads, did you spot them? Now I have to do the same exact thing to the other half of the amp module - oh BOY!!

 

[wildwill532]

Impressive work, do you see/notice any difference with a 2600 vs a 2500 and the legendary 2385 if youve done one, just curious if there's any real differences or just a little more power and scope for the 2385?

 

[Denten]

Impressive work, do you see/notice any difference with a 2600 vs a 2500 and the legendary 2385 if youve done one, just curious if there's any real differences or just a little more power and scope for the 2385?

The biggest difference between the 2385 and the 2500/2600 is the amp module, the 2385 uses passive cooling, Passive cooling means that heat from the power amp is dissipated into an aluminum heat sink. This is done by passive convection (the natural law that hot air rises). The 2500 and 2600 uses active cooling, Active cooling increases the cooling effect by using a fan to force air across the heat sinks.
The 2385/2500/2600 all share the same chassis, and are basically three variations of the same receiver. IMO

 

[catrafter]

Beautiful workmanship!

Tom

 

[rBuckner]

Impressive work, do you see/notice any difference with a 2600 vs a 2500 and the legendary 2385 if youve done one, just curious if there's any real differences or just a little more power and scope for the 2385?

I have not worked on a 2385 as of yet but Tom has, maybe he'll pop back in and comment. Tracy (Denten) is pretty knowledgeable so I bet his observations are quite correct. For sure the 2385 doesn't have the fan. I'd bet the transformer has less iron and wire inside it too.

Between the 2600 and the 2500, there's not much difference at all. The power transformer is different to get the higher voltage the 2600 needs to make the additional wattage. The 2600 adds the quartz lock gimmick so the FM buffer amp is a bit different and the phase lock board is added. I bet the front end is a bit different too to allow the PLL to do it's adjustment, I didn't try to study the difference but can if there's any interest. The front end looks the same for the most part.

Thanks all for the nice compliments!

 

[mech986]

Beautiful workmanship!

Tom

+100 A labor of love or perhaps a high level of OCD! I know I'd sure try to do it this way. Excellent skills!

 

[mech986]

Man, this 2600 is going to look better than when it was assembled at the factory. Wonder if you could get TMZ2 to make a one off black faceplate to really become a striking one off?

 

[catrafter]

The power amp is totally different between the 2385 and the 2500.

Tom

 

[wildwill532]

I've emailed someone on eBay who produces the new black faces and asked for a 2600 and was told sorry they won't do it basically?

 

[KutzlerTrans]

Very nice work Randy, Your attention to detail is top shelf!

 

[Denten]

Here are pictures of my 2385's power amp for Comparison.

 

[Denten]

Randy, thank you for taking the time to put this thread together, it is threads like this, put together by you and Tom, and all the other pro's, that made it possible for this small engine mechanic to bring a dirty, broken, unloved and unwanted sweetheart of a receiver back to it's former glory! this would not have been possible without AK and all you top rate techs that take the time to help and share.
For me to stay in the game it is very important that I know every inch of my 2385, I am soaking all this info up like a sponge.

 

[rBuckner]

Thanks for posting those Tracy, looks nice and clean in there! I'm so glad to have helped you along if I did. It appears that the 2385 chassis may not have the bottom sub chassis plate. That wouldn't have worked well with no fan. It only bolsters my opinion that the 2500's development was hurried along. By that I mean maybe they took the 2385 and drew up a bottom plate to add in so they could have a place to screw down the heatsink tunnel assembly. It looked awkward to me when I saw it and it sure is!

The 2385 amp board does have the same "flavor" as the 2500/2600 one.

I've finished reassembling the amp tunnel halves on the 2600 but have been sidetracked so far this weekend as far as going any further. I'm burned out on cleaning and regreasing/reinstalling outputs, all 16 of them! I'll be back at it very soon.

 

[Denten]

Thanks for posting those Tracy, looks nice and clean in there! I'm so glad to have helped you along if I did. It appears that the 2385 chassis may not have the bottom sub chassis plate. That wouldn't have worked well with no fan. It only bolsters my opinion that the 2500's development was hurried along. By that I mean maybe they took the 2385 and drew up a bottom plate to add in so they could have a place to screw down the heatsink tunnel assembly. It looked awkward to me when I saw it and it sure is!

The 2385 amp board does have the same "flavor" as the 2500/2600 one.

I've finished reassembling the amp tunnel halves on the 2600 but have been sidetracked so far this weekend as far as going any further. I'm burned out on cleaning and regreasing/reinstalling outputs, all 16 of them! I'll be back at it very soon.

Are you saying, they just tacked a plate onto a 2385 sub plate? Because that is what it looks like they did. The 2385 and 2500 came out at the same time, at the time the 2385 (marantzs #2 was more powerful than the competitions #1) so why build the 2500? was it a after thought?