Cleaned Up Marantz 2230 - now, no AM section and FM lost some sensitivity

[Catfish Phil]

This was one dirty, filthy 2230 - clean under the chassis but dirty on the top side, with rusty transformer and tuner boxes, missing button on a broken power switch, almost all bulbs burned out and scratchy pots.

Brought up the voltage slowly and wow, it came back to life.

Sprayed out controls, and everything was fine - nice and loud, good on AM and FM, so proceeded to clean up the cigarette smoke damage by vacuuming out everything and then washing off one pc board at a time with alcohol and a plastic brush. Helped out the drying process by vacuuming every pc board after the wash/rinse/repeat cycles. Let it all dry a day or so before powering it up.

The amp section sounds great but I am hearing a loss of sensitivity on the FM band and loss of the AM band altogether.

So, trying to figure out where I went wrong when doing the following things:

The two tuner section box tops were rusty - removed them, removed the rust off the variable capacitor box but the smaller shielded box lid was nasty. Wire brushed it, rust treated and painted it.

Removed the ferrite rod antenna to clean it and the mounting bracket. Wondering if one of the ferrite antenna wires is stretched/broken where it enters the rod housing. Marantz used the shortest piece of wire in the factory on this one. Thinking if the red wire is broken at the antenna, no signal is getting to the AM tuner section. A little fearful of disassembling the ferrite antenna and cracking it in an attempt to see if the wires are broken.

Was careful to not disturb any of the toroid coils but some of the alcohol could have found its way into one.

The receiver has been on and working 12-14 hours/daily for the past five days. Everything is running cool, and the FM sensitivity seems to have improved a little bit, but the AM band is still dead. AM was working well before the cleaning.

Any ideas?

 

[Catfish Phil]

Okay, FM sensitivity is back, AM getting better. The ferrite antenna is okay. Could be there was some moisture in the cans from my semi-rigorous cleaning with alcohol, and it's drying out. Been running it ten - twelve hours a day or more.

Finally ordered a bulb kit, so will search the forum for how to replace the dial lights. I can disassemble the tuning string system and remove the tuning dial. Or is it easier to remove the plastic from the front? The latter seems dangerous - don't wanna crack the plastic.

This is really a solid receiver - the power transistors always stay cool, it's loud, and fairly clean-sounding. But wow, this was one dirty stray of a receiver. Not complaining - it was included for free with the $15 purchase of an old Advent cassette deck!

 

[runningdog]

Do you plan to replace the diffuser behind the dial face? If so then take off the faceplate to get to it. It's real easy to install the dial lamps that way. For the indicator lamps remove two screws holding the upper lamp board to the lower board and ease it out. You may have to disconnect the power lead.

If you do not plan to replace the dial diffuser, then you can remove the lower lamp housing from the back. Just barely.

The 2230 has a metal lamp housing so you don't have to worry about it crumbling as some of the plastic ones do.

It's great you are bringing it back to life!

 

[Catfish Phil]

RD, kool! I had the dial face halfway off and know with a razor blade the adhesive could be persuaded into releasing the dial face. After that, I can remove the diffuser and reach the bulbs. Now that I know this is acceptable practice, it sure would be easier than disassembling from the rear. I can replace the diffuser with the appropriate Lee diffusion filter (full, 1/2 or 1/4) - I have a nice Lee filter assortment pack for my photography studio.

The lamp kit has everything, so everything will be replaced, including the bi-pin indicators - nice to know those will come out fairly easily. Not really afraid to disassemble the entire chassis front, but nice to know it's okay to take it from the front.

Thank you so much, Runningdog. Yeah, this ol' 2230 is quite solid! I also have a Realistic Modulaire 12-1403 (my very first receiver), my brother's Pioneer SX-450 and a one owner Sansui G9000. The SX-450 runs hot! And the Modulaire, so dinky yet so reliable, has tiny output transistors but has also performed so reliably all these many years. There are other receivers around here but these 70's silver face rigs are my favorite.

Honored to finally add a Marantz to the fold.

 

[thxdave]

I can replace the diffuser with the appropriate Lee diffusion filter (full, 1/2 or 1/4) - I have a nice Lee filter assortment pack for my photography studio.

Phil, I used Rosco 111 diffusion on my 2275 and you'll want the full strength Lee material. The 1/2 and 1/4 will reveal too many hotspots. You might even consider Tough Spun (#261). Just one audio-loving photographer to another!! ;-)

 

[Catfish Phil]

Phil, I used Rosco 111 diffusion on my 2275 and you'll want the full strength Lee material. The 1/2 and 1/4 will reveal too many hotspots. You might even consider Tough Spun (#261). Just one audio-loving photographer to another!! ;-)

Ha ha! Lee #216 Full Diffusion it is, then - I was going to push tungsten through the Marantz stuff and take a reading on the Seconic L-356, then work up a gel combination to match it.

Nice to know there are photographers in addition to the normal people on this forum. And I was in broadcasting before photography, so audio is my first love.

Guessing contact cement would be a good choice to glue in the new gel.

Thank you so much for the tip!

 

[thxdave]

Honestly, using Rosco or Lee is overkill but with 40+ years in the business, you accumulate a lot of lighting detritus. If I had stayed with tungsten lamps, then the heat-resistance would make perfect sense as it would never discolor or fail. But, if you were starting off with nothing available, buying new filter sheets is a little pricey. I'd probably go with the vellum that most everybody here uses.....but you and I are nuts so we'll use whatever photo stuff we have laying around. ;-)

 

[Catfish Phil]

Honestly, using Rosco or Lee is overkill but with 40+ years in the business, you accumulate a lot of lighting detritus. If I had stayed with tungsten lamps, then the heat-resistance would make perfect sense as it would never discolor or fail. But, if you were starting off with nothing available, buying new filter sheets is a little pricey. I'd probably go with the vellum that most everybody here uses.....but you and I are nuts so we'll use whatever photo stuff we have laying around. ;-)

Figured out how to simply replace the bulbs from the inside of the receiver. Just had to unsolder one thing, unscrew the panel and replace the five fuse-type bulbs. Did the same thing for the selector bi-pin bulbs.