[Ron Ramirez]

So today I finished replacing electrolytics in the original tuner board, and (using a grounded wrist strap) installed the other NTE IC I had in place of the original.

Results:

Basically the same as the first board, only there is evidence of life on AM although it is barely picking up anything on AM.

Then I had a thought...is replacing the electrolytics throwing off the alignment that much?

I'm tired and my brain is still not functioning 100% thanks to all the chemo.

At this point I would be much obliged for any help; otherwise it is going back on the shelf to be sold at a later date "as-is - for parts". I've invested way too much time on this one already over the space of a couple years and I'm really getting tired of messing with it.

[rfeenstra]

I can relate!  Been working on a Bogen C100 used in a Maas-Rowe carillon.  Has given me fits over the years.  Sat for about 3 and I decided to give it one more try.  After blowing several sets of output transistors  I think I finally have it solved.  Maas Rowe puts a delay in these amps that lifts the ground to the output terminal for about 5 seconds.  I discovered that the amp went into oscillation all the way to clipping during that period.  Never saw it on the scope cuz the ground was lifted.  No power delivered to speakers but I guess the outputs didn't like it for very long. Still can't figure out why it does it but by bypassing the relay, all is well.  Not scratching my brain any more on this thing!

let it sit for another year, Ron.  Then give it one more try.

[Ron Ramirez]

Actually, a Phine Phorum Phriend has volunteered to look at it, so...if I can come up with a suitable box, this Marantz is going on a little trip.

I really appreciate the offer of help (you know who you are). I am really tired of looking at this thing.

[Ron Ramirez]

Good news:

My Phorum Phriend has informed me that the 4230 is up and running again. The culprit: a bad transistor in the FM IF section of the tuner board.

I want to express my sincere appreciation for his taking over the job. After you mess with something so long, too often your brain becomes fatigued and you start second guessing yourself..and your progress comes to a complete halt. This is where a second pair of eyes always helps.

[EdHolland]

That is good news indeed. It is always satisfying to solve the mystery... pesky three legged fuses 

[Ron Ramirez]

It's back home and now set up next to the workbench in the basement:

   

That dial certainly looks good with all LED lamps.

And that is it for this thread.

[Stall-U-Rated]

PURRRRRDEEEEE!!!

This experience reminds me of the Sansui 90/90 i have parked on a shelf. Ran when i parked it, unsure if i wanna get back into it..

Steve

[EdHolland]

Oooooooh. Nice!

[Ron Ramirez]

I should mention that it's been more than a month now...and the 4230 continues to work well by my workbench.

Thanks again Ed L. You did a great job on this tough dog Marantz.

[Paul Philco322]

the large flywheel tuning wheel, blue lite, very sexy. 

Paul

[Eliot Ness]

That's a beautiful receiver Ron, I'm glad it's back in service!

[EdHolland]

Gorgeous