Troubleshooting Marantz 2245

[Joe Kramer]

Hi Friends,

I just inherited this unit, whose previous (and original) owner was a cat and cigar lover. But the fact that the knobs and faceplate were literally bronzed with nicotine, and that it still smells strongly of smoke and cat urine after a thorough cleaning is the least of the problems at the moment. There seems to be no signal from one channel. I managed to determine that both sides of the power section worked by use of the MONO button, and so I'm pretty sure the problem lies in the preamp. However, after spraying out the switches and pots with De-Oxit, now the MONO button trick has no effect, though I'm still fairly sure the trouble is in the pre section.

My question: are there any "usual supsects" with this model that might help me zero in on the problem--say, electrolytic failures, etc? I do have the schematic, but I'm not too thrilled about the prospect of tracing out the whole dang thing unless I'm confident it can be a one-day sort of job. Otherwise I'm tempted to take it to a service center.

Any help much appreciated!

Regards,
Joe

[Netlist]

Joe,
welcome.
I doubt you will find a service centre that will want to tackle that job. Indications are not that good and making this beauty back to work is a time consuming task. Diy is the only way to go. What worries most is the cat urine. Look at the copper traces and component legs is they are oxidized. A few locals can be fixed but if it's all over the place, you'll have a though time. Bad solderings and worn out caps, crackling pots and faulty trim pots are the most common errors to look for.
If it weren't a receiver, I would apply the dishwasher method to clean it.

Good luck and keep us posted.

/Hugo

[Joe Kramer]

Hey Hugo,

Thanks for your reply. I think you're right in general about finding someone to service this old thing, but I happen to be fortunate enough to live not too far from an authorized MacIntosh dealer who also carries and services Marantz. They would be my only choice if I were to go that way. I'll take your advice and give it a fine tooth combing over. Thanks again!

Regards,
Joe

[Netlist]

There is a lot to learn from these old solid states. In general, basic servicing is rewarding because of the openness of the design.
You don't need expensive soldering tools, no magnifying glasses etc...
I'd give it a go if I were you, of course I have no idea of your experience with electronics.

/Hugo

[MOER]

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[B Cullingford]

switches...

clean them, clean them again, maybe disassemble and clean (tricky but it can be done) - if one channel is out for all inputs always suspect the tape monitor switch - it does not get used by many people

But if there is feline urine in the set then all bets are off - when I was fixing sets this was one of the few things that I would say no to. It stinks, is very caustic and therefore is very hard to guarantee and I hated to fix something twice. Becomes a labor of love. If there is damage from liquids as soon as possible rinse well with clean water (tap is ok) in a bathtub or whatever, get the worst out (shake?? reminds of some huge amplifier that the manufacturer told you to shake to check for loose screws once reassembled - it was as much as most of us could do to lift it!) and dry thoroughly before turning on.

If the liquid has been there for some time all kinds of nasty things can happen, some are real obvious, but some are not I've seen components that look fine and the board around them looks fine but one lead is completely eaten away - hence as a pro it was best to stay away from these sets. DIY well thats different, I once for myself took every component off the PCB, cleaned and repaired the PCB, checked every component and reassembled - lots of work, but fun in its own way.

The other liquids that are bad are coke (the drink) and water dripped from plants (why would you put your stereo below a plant?!?).

Cats seem to like laying on the warm sets, sometimes you just have to deal with the fur and dander, but sometimes...

So I guess I'm saying try cleaning first, and second, and when it is thoroughly ckean and the switchs are clean and known to be working then, and only then look else where.

Good luck, Bill

[Bane2871]

I'm got a 2245 that has lost audio as well, in both channels (though no cat pee or nicotine is involved in my case). For a while I would need to turn the volume up fairly high before I'd get anything to the speakers. Once the juice was flowing I could choose any volume level I wanted.

Now, there is no output at all. I turned the volume to max (cringing while I did so) but nothing happened. This is the same for all input sources.

Any suggestions as to where I should start? I did buy a service manual on eBay, which hasn't arrived yet.

Thanks

[MatthewK]

Originally posted by Bane2871
For a while I would need to turn the volume up fairly high before I'd get anything to the speakers. Once the juice was flowing I could choose any volume level I wanted.

Now, there is no output at all. I turned the volume to max (cringing while I did so) but nothing happened. This is the same for all input sources.

This sounds like the same behaviour my 2285B showed when it had a bad relay power supply. Try tapping the top of the case to see if it suddenly switches the speakers on. If so, it's probably a bad capacitor in the little relay board - at least replacing those on my 2285B solved that particular problem.

For the original poster - if you have access to an oscilloscope it should be relatively straightforward to attach a source and follow through the circuit seeing where the signal gets to. Aside from signal-path caps, the relay, speaker switches, mono switches, tape monitor switches, source selector switch, tone control range switch (if any) and the pre-out / main-in jumpers, which may be internal, are all suspects. Remember the DeOxit has to get into the control, but you then need to work it a couple of dozen times and wait for it to dry.

[Bane2871]

Thanks.

Any other maintenance/improvement items that may be worth doing while I have the thing opened up?

[anatech]

Hi Bane2871,
Clean all the dust and debris out first and take some digital pictures before you do anything. Check the main filter caps for broken or leaking seals.

Get a service manual or schematic before going further. Refer to it often. Before you start, measure the DC offset and bias currents. This tells you some things. Close the tuning cap up so it doesn't get damaged as you work (plates meshed together).

Now, replace all the electrolytic caps in the low voltage power supplies, the amplifier boards and the tone board. Clean the controls and switches at this point in time. Make sure you do not get any cleaner into the tuning capacitor or any of the trimmers.

If you replace the dial lamps, make sure you do them all at once. You must use 8V 200mA "fuselamps". Most have higher current ratings that will ruin the reflector for the tuning dial.

Lastly, do not twiddle any controls or adjustments without a clear understanding of what you are doing. This is especially true of the RF stages. If you think you know, you don't. Yo must know what you are doing.

Not a bad set BTW. Nice find.

-Chris