Marantz 2275 FM board question

tclaborn

New Member
20171207_161942.jpg Hello, I just spent over a year leasurly recapping a beutitful 2275, I took pictures of my reassembly and just as I was closing up the case, I noticed that the pointer light goes out.
I went on eBay and picked up a p100 board from a 2270. The 2270 matches the SM from HiFi engine. It does not match the board in my 2275.

Will it work?

Clue 1 - The 2270 board is gold, my 2275 board is green and brown like all the other boards I have just restored.
Clue 2 - The front end is attached to 6 posts and they are not wire wrapped, they are soldered. Fm reception is not steller but I do get the stereo light. I wonder if this board has been switched out before, Or at least been removed and soldered in. The board I have in the 2275 has a couple less resistors at the top. and the 2270 p100 has an exact match for the scematic form the SM.View attachment 1061097 View attachment 1061101
 

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I was thinking of a repair attempt, especially since I have the backup, I just want to make sure it is compatible. Maybe a change of resistors and transistors? I get no reading of current at the 2 prongs connecting the pointer bulb.

Cat, Are your six points on the p100 board wire wrapped or is it the 1 board that is soldered in?

I managed not to unwrap a single board in the recap and I even left the original pointer bulb because I did not want to splice the wire. I do have the LED that came with the kit. But I don't mind Unsoldering a soldered board. I have a rudimentary understanding of resistor stripes but these colors are faded. I would also need to know what the new KC replacement parts are. Helpppp!
 
The dial pointer bulb has nothing at all to do with the front end! It has 8Vac switched to it in the AM and FM modes by the function selector switch. I bet it's just a burned out bulb.
 
The dial pointer bulb has nothing at all to do with the front end! It has 8Vac switched to it in the AM and FM modes by the function selector switch. I bet it's just a burned out bulb.

I get no reading at the bulb wire terminals and the LED won't light from them either, although it will using a 9v battery. It has to go through the P100, that's where the wires attach.
 
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Some reassembly pics, I kept every set of screws labeled.
 

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9v on a led is a quick way to burn it out- they are rated for around 3v. If you have installed a LED did you put a resistor in line with it? As well, LED's are directional- it's a diode. Did you try reversing your wires?
 
I cleaned it durring the restoration. Would recleaning light the pointer?
I just re cleaned with CRC and added a touch of Faderlube on the shaft connectors (no improvement after spinning a zillion times) I guess I had done a good job the 1st time, but the thread said to wait a few days. Great thread thanks for pointing me to it.
 
9v on a led is a quick way to burn it out- they are rated for around 3v. If you have installed a LED did you put a resistor in line with it? As well, LED's are directional- it's a diode. Did you try reversing your wires?
It's supposed to be a drop in replacement 8v LED see the green bubble wrap in the picture. Just tried again with the wires both ways no power. Volt meter shows no power to the wires.
 
Then you need to trace, could be a break in a wire somewhere. You can test the led with a dmm set in diode mode , it should light up.
 
The dial pointer bulb has nothing at all to do with the front end! It has 8Vac switched to it in the AM and FM modes by the function selector switch. I bet it's just a burned out bulb.
You Sir, were absolutely correct. Strange that it blew at closing. lol.
 
Do you happen to know if the FM board from a 4270 is the same as a 2270?

I have a 4270 that still needs some tuner love. It works, but drifts, I was thinking of recapping another board, swapping it in, then taking it back to tech for an alignment. That way if I completely bone something up I can always drop back to working but drifting.
 
Since older Marantz gear has no AFC, tuner drift is usually caused by a 'dirty' tuning capacitor.
There is a great thread by dr*audio on how to clean it.

Tom
 
I've just finished cleaning the tuning cap on a 2270 that stopped pulling in stations, wouldn't goto stereo.
I followed *most* of the instructions, was very careful and the tuner now seems to work find. Good (not great) reception, it does goto stereo. I'm happy.
That's a great thead for tuner cleaning.
I'll be recapping most of the rest of the unit, but I'll be leaving the tuner alone.
:jump:
 
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