Marantz 2600 Refurb Thread

[rBuckner]

All day FedEx claimed my parts package was to be delivered but it never hit Phoenix even until 5PM so I sure didn't get it but will tomorrow. I got a few minor tasks done though.

I took a few reference shots of the scope tube still in it's shield in case I needed the for realignment.

For the record, here's the brand and part number label.

After cleanup the parts look much nicer! I didn't spray the tube but wet a piece of paper towel with Windex and wiped it down and followed with a piece of dry paper towel.

The whitish band near the back of the tube is rubberlike and the clamp left an indentation that I used to reorient everything. The shield had scratch marks where the clamp screws were so that is where I retightened them to. I'll check it once it's all in and operating and readjust it.

I did get my hardware shipment in Friday so replaced all 4 nylon screws on the two heatsink assemblies of the scope amp board.


There's some maintenance and cleaning to do this evening still - how fun!!

 

[rBuckner]

Oops, it double posted and there's no delete option.

...and GREAT! When I deleted the text and pictures in one of the posts, both disappeared. Thanks Xenforo... I'll repost when I have time = not now!

 

[rBuckner]

Removed the old LEDs and cap on the function LED board. I noted that there is no "+" on the e-cap silkscreen and that the rectifying diode is screened backwards. The e-cap is shown backwards on the schematic.

Time to machine the snout onto the LEDs. Here one is chucked for removing the lip on the back so it can be chucked properly the other way around.

After multiple passes the required diameter of .090" is dialed in.

Next is a fine sanding, a very fine sanding and polishing. It doesn't come out super clear but the idea is to keep light from spilling out sideways and if the end sticks out a bit the appearance will be good.

New vs. old. The curvature of a T1-3/4 LED makes for a domed end.

All of the LEDs needed are ready along with the warm white LED fuse lamps.

 

[rBuckner]

Before tackling the broken lamp housing I decided to reinstall the scope board and tube assembly.

The filter cap rebuild caps are here!

OK, time for the dial lighting rework to commence. First the trim piece and the dial pointer bracket come off.

Then the dial can be pried off. There is no vellum paper on this type dial.

Spotted the first crack...

I think the lamps are all originals. They had a lot of silvering inside.

One of the tabs was busted off and still inside the lamp housing.

 

[rBuckner]

The lamp parts all got a washing then I started in on regluing the switch opening bushings back in. I got them all started with 12 minute epoxy and later finished gluing the rest of the stepped perimeters.

SO it looks like backwards progress!!

Back to the lamp housing, it is busted into two major pieces and has some other cracks. There will be repairs done with modeler's styrene plastic strip stock when I get back to it.

I then removed the two rubber blocks that hold lamp bulbs for the "stereo" and "Dolby" functions and got the bulbs out unbroken even! The rubber blocks are very hardened by heat and age. They got washed and the old glue picked off. I'll be stuffing a set of 3 T1 sized true red LEDs into each.

 

[Denten]

There is no vellum paper on this type dial.

They must have changed that in 1978 because my 2385 has the same dial and it has vellum.

The filter cap rebuild caps are here!

Those caps look big on my 32" monitor lol, are you stuffing 8 caps in each can? They must be smaller than they look. You are lucky I'm not your neighbor, I'd be ringing your doorbell every time I smelled your soldering iron warming up.

 

[Bkphoto]

great stuff...

 

[rBuckner]

...
Those caps look big on my 32" monitor lol, are you stuffing 8 caps in each can? They must be smaller than they look. You are lucky I'm not your neighbor, I'd be ringing your doorbell every time I smelled your soldering iron warming up.

Yep. A kind member pointed out this combination to me recently and I need to look back and find that to give proper credit.

Tracy, you can come by and spend some time in the shop any old time!!

 

[rBuckner]

I got the LED board reattached and the new LEDs soldered in yesterday. Lookin' pretty! I chose the green ones I did for their slightly truer green color than the usual green ones.

I had earlier touched up some damaged lettering. It's not perfect but looks much better. I used gloss black modeler's enamel paint and a small 15/0 size artist's spotter brush. There was damage on "power", "volume" and "phones".

There was a hit to the left of the "PHONO1" lettering and because of metal damage it was impossible to get a straight edge on the left side. It was totally missing before so it's better than not trying at all.

Next up was soldering some T1 (1/8" diameter) true red LEDs in series for the "stereo" and "Dolby" lamp replacement. It's easiest to just tape them down, solder quickly and cut the leads.

The end leads are then formed inwards and bent up to exit the top of the rubber housing. I put some recycled tubing on the negative lead to make sure to prevent shorts.

Last test firing before epoxying them into the housing.

 

[Denten]

Tracy, you can come by and spend some time in the shop any old time!!

Sounds like a plan Randy! You are only 2,270 miles away, I can be there in 33 hours if I drive straight through.

 

[rBuckner]

Today (Friday) the next mission is to repair and strengthen the brittle lamp housing. I've already used thin super glue to repair the cracks that didn't result in separation. It's so brittle I dared not do any more repair without securing it to the metal bracket it normally would squeeze into. As you can see, I bumped into a support arm and >tink!<, it popped off. I'll be using modeler's liquid cement and various viscosities of super glue.

I used thick super glue to reattach it. I plan on adding some strip styrene on the inside to bolster it. I can't use any on the outside as is seen as that's where the lamp board seats.


So I'll be doing work on it here and there throughout the day in between other tasks, the first of which is lunch with a buddy. Later today AK member 'Sherwoody' is dropping by. He and his lovely wife are selling their house and looking for a place here in town which will be cool!!

 

[rBuckner]

Now after lunch, I got the small busted out piece with the ear tab on it glued in and clamped. I'm going to let it set up awhile before messing with it.

The chassis ground screw for turntable grounding was stripped out and was ridiculously small anyway. I like the beefy one I found at Mouser which looks like it could take a banana plug as well as spade lugs and wire ends. The old one had a screwdriver tip busted off in it and was rounded over from many plier tightenings.

The old hole need drilled out to 1/4" and the lip inside ground with a Dremel tool, then the adjacent RCA jack block had to be loosened for wrench access. It tightened up well and all was reassembled.

That's it for what I can do until the lamp housing is fortified and reinstalled. With that done I think I'll get all of the adjustments done. I can also then select the resistors for the function and tape monitor LEDs and rewire the stereo and Dolby LEDs. Also to be done is an AC to DC converter for the scope graticule LED conversion. Then I can go after the filter cap rebuild. I can't finish that off until Monday when I can access the potting epoxy machine at work. It's getting near completion!

 

[rBuckner]

After a nice dinner out with my two sons, the oldest hit 33 today, I did the last of the Friday fixes. I add bracing to the top outside edges.

Then on the inside I added .080" thick strips to make for a long brace.

Here is the long brace on one side. The other side dips in so I cemented one end down and will add some medium super glue before bedtime to strengthen it. In the morning I will clamp the other side and flow plastic cement and after a few hours will superglue reinforce it too.

 

[mech986]

Man, wouldn't it be nice if someone 3D printed those plastic lamp housings?

 

[Denten]

Man, wouldn't it be nice if someone 3D printed those plastic lamp housings?

Parts like this can be easily molded and recast using THIS technique, I will be experimenting with this technique this summer, my lamp housing is not brittle yet ( low hours) so I need to make a mold before it is to brittle, once the mold is made it can be recast in a variety of different materials including white acrylic, and the mold is reusable. I will start a thread on this subject this summer.

 

[rBuckner]

Man, wouldn't it be nice if someone 3D printed those plastic lamp housings?

I have used these about 3-4 times now and I don't like them. When you have an unusable original they are a good thing though. This was not on the 2385/2500/2600 type models that I have used. The fit is always off and requires rework, usually just some filing. Light leakage is a big issue with these as well. Sometimes I've had to put on 3 coats of black paint then a couple of white coats.

Parts like this can be easily molded and recast using THIS technique, I will be experimenting with this technique this summer, my lamp housing is not brittle yet ( low hours) so I need to make a mold before it is to brittle, once the mold is made it can be recast in a variety of different materials including white acrylic, and the mold is reusable. I will start a thread on this subject this summer.

That was an interesting video. I am also a model builder and someone in our local model club demonstrated simple mold making to make parts from a master. The favored material for making the parts was a resin made for orthodontic usage. Alas, that older fellow has moved out of state. I'd love to see your experiments when you get to playing with it Tracy!

 

[Denten]

I am also a model builder

So you must be familiar with "Waterslide Decals". Picture this and see what you think, I can extract just the script from my faceplate, what if I printed out the silk screening, to scale, on waterslide paper, then seal the decal with mat finish clear to take the gloss of, then after applying the waterslide decal(s) to the faceplate, seal the whole faceplate in as many coats of clear gloss or mat finish as needed to hopefully make the edge of the waterslide disappear. I have been researching waterslide decals for a while now as a possible fix, the trick is to make the carrier invisible. The silk screening on my receiver is a 10 out of 10 and I don't need a new lamp housing, I just love problem solving.

 

[rBuckner]

Very interesting idea!

I have a trashed face plate you can experiment on - just say the word. I'm familiar with these decals and as they have a thickness they will be difficult to eliminate the edge with clear coats. At least without getting it so thick the graining of the aluminum will look goofy. A semi gloss for the final coat is what I'd try as a normal plate isn't dead flat although it would hide the decal better. Clear coats I don't believe would stand up well to time as far as yellowing and wear unless an automotive grade clear was used although I'm not sure flat or semigloss would be available. Also of concern would be the graining's effect on initial decal application as they like a flat surface. Any imperfection, even a flat paint on a model can easily result in "silvering" as the decal can't conform well to the surface. There are decal softening solutions (literally!) out there to soften decals to help settle them in place.

I wonder if dry transfer would work. I don't know the process to make them. That would just leave the lettering in place with no carrier to stick up. It would have to be clear coated.

 

[rBuckner]

The back side of the housing, which had cracked, now is getting a beefing up using thin .010" thick by 1/4" wide strips. They easily curve to fit.

More are laid up.

After a couple hours curing time, they were sanded flat to allow a second layer to adhere well. These will span the seams for best strength but not go as far across. I didn't feel as if I had to put half wide strips on the ends. This second layer is like overkill but I'm enjoying the process!

I figure the other side should be done preventatively.

 

[rBuckner]

Finally! The housing is done and spray painted.

The two lamp holder blocks (with the red LEDs) are slid in place and then the housing went back on the bracket. Here it si sitting loose. The LED fuse lamps have been inserted into the clips.

After a coat of carnauba wax, the dial is reinstalled with double sided tape. I had to remove the finishing frame first but it's back on here.

This is on the right side and the low side wire for the Dolby LED set has been soldered on. It is switched to ground by the Dolby decoder. I used some heatshrink tubing but I won't be sticking my soldering iron in there to shrink it with the dial cord so close! I later put a dab of epoxy on all of the places required.

On the high side I soldered on a re wire that will connect to the +13.5Vdc supply via whatever dropping resistor makes the proper brightness.

The top left side and the connections are made to the "stereo" LED.

Here's the pretty face all lit up! I jumped the Dolby LED to ground to light it. There is no decoder in this 2600 is why I "cheated".